Tenecteplase: A Comprehensive Pharmacological and Clinical Review

1. Introduction to Tenecteplase

Tenecteplase is a third-generation thrombolytic agent, representing a significant advancement in the pharmacotherapy of acute thrombotic events. It is a genetically engineered variant of human tissue plasminogen activator (tPA), a naturally occurring serine protease integral to the endogenous fibrinolytic system.[1] The primary clinical utility of Tenecteplase lies in the emergency management of conditions where rapid dissolution of blood clots is critical, most notably in acute ST-segment elevation myocardial infarction (STEMI) and, following more recent investigations and regulatory approvals, in acute ischemic stroke (AIS).[1]

The development of Tenecteplase was driven by the objective to improve upon the characteristics of earlier generation tPAs, particularly alteplase. This was achieved through targeted modifications to the tPA protein structure, resulting in an agent with enhanced fibrin specificity, a greater resistance to inactivation by its principal physiological inhibitor, plasminogen activator inhibitor-1 (PAI-1), and a considerably longer plasma half-life.[2] These refined pharmacological properties confer a major practical advantage: the ability to administer Tenecteplase as a single, weight-adjusted intravenous (IV) bolus. This simplified administration contrasts with the more complex bolus and infusion regimens required for older agents like alteplase.[2]

The capacity for rapid and straightforward administration is of paramount importance in time-sensitive medical emergencies such as STEMI and AIS. In these conditions, the adage "time is tissue" underscores the direct correlation between the speed of reperfusion of an occluded artery and the extent of salvageable myocardial or cerebral tissue, respectively.[3] The molecular engineering of Tenecteplase, therefore, not only aimed to optimize its biochemical interactions at the site of thrombosis but also to streamline its clinical application, potentially reducing treatment delays and improving patient outcomes. This strategic approach in pharmaceutical development, focusing on bioengineering existing therapeutic proteins to enhance their clinical performance and ease of use, is exemplified by Tenecteplase. The rational drug design employed targets specific limitations of the parent molecule, alteplase, showcasing an efficient pathway to therapeutic advancement by refining known biologics. Furthermore, the single-bolus administration capability is not merely a matter of convenience; it is a critical factor that can significantly influence patient outcomes in hyperacute settings by facilitating broader and more rapid implementation of thrombolysis, especially in pre-hospital or resource-constrained environments.

2. Molecular Profile and Formulation

2.1. Biochemical Nature and Recombinant Origin (Biotech)

Tenecteplase is classified as a biotech drug, specifically a glycoprotein composed of 527 amino acids.[1] Its production relies on recombinant DNA technology, utilizing established mammalian cell lines, most commonly Chinese Hamster Ovary (CHO) cells.[2] This method of production is crucial for ensuring that Tenecteplase undergoes appropriate post-translational modifications, such as glycosylation, which are similar to those of native human tPA and are important for its stability and function.

2.2. Key Structural Modifications (T103N, N117Q, KHRR→AAAA) and Their Significance

Tenecteplase is distinguished from native human tPA by three specific amino acid substitutions, which have been bioengineered to optimize its pharmacological properties [1]:

1. A substitution of Threonine by Asparagine at position 103 (T103N).
2. A substitution of Asparagine by Glutamine at position 117 (N117Q), located within the kringle 1 domain.
3. A tetra-alanine substitution for Lysine-Histidine-Arginine-Arginine at amino acid positions 296-299 (KHRR296-299AAAA) within the protease domain.

These modifications are highly targeted and confer distinct advantages. The T103N substitution creates an additional N-glycosylation site, while the N117Q substitution eliminates a glycosylation site in the Kringle 1 domain. These alterations to the glycosylation pattern are primarily responsible for Tenecteplase's reduced plasma clearance and consequently, its prolonged plasma half-life.[2] The KHRR→AAAA substitution in the protease domain is pivotal for enhancing the molecule's specificity for fibrin and significantly increasing its resistance to inactivation by PAI-1.[2] This sophisticated understanding of tPA structure-function relationships, where each mutation addresses a distinct limitation of native tPA (e.g., short half-life, lower fibrin specificity, PAI-1 susceptibility), demonstrates a high level of precision in protein engineering to achieve desired clinical attributes. The Kringle 1 domain modifications primarily influence pharmacokinetic properties, whereas the protease domain modification primarily impacts pharmacodynamic properties, representing a dual optimization strategy.

2.3. Physicochemical Properties and Formulations

Tenecteplase is typically supplied as a sterile, white to off-white or pale yellow, lyophilized powder.[2] Prior to administration, it is reconstituted with Sterile Water for Injection, USP, yielding a clear, colorless to pale yellow solution.[2]

Several formulations and brand names for Tenecteplase are available globally, reflecting its widespread clinical use:

• TNKase®: Marketed by Genentech (a member of the Roche Group) in the United States and Canada. It is available as lyophilized powder in 25 mg and 50 mg single-dose vials for reconstitution.[1] A 25 mg vial configuration was specifically introduced to support its use in AIS.[3]
• Metalyse®: Marketed by Boehringer Ingelheim in various regions outside of the US, Canada, and Japan. It is often available in strengths denoted in units, such as 5000 units (equivalent to 25 mg), 8000 units (40 mg), and 10000 units (50 mg).[1]
• Elaxim®: A biosimilar tenecteplase developed and marketed by Gennova Biopharmaceuticals in India, available in 30 mg, 40 mg, and 52.5 mg vial presentations.[10]
• Mingfule®: A tenecteplase copy version marketed by CSPC Pharmaceutical Group in China.[5]

The global presence of these multiple brands and biosimilar/copy versions underscores Tenecteplase's established therapeutic value. However, it is important to note that biochemical differences may exist between originator products and copy versions. For instance, studies comparing Mingfule® with Metalyse® have reported variations in clot lysis activity, proportion of the two-chain form of tenecteplase, receptor binding characteristics, and host cell protein content.[5] Such differences highlight the critical importance of rigorous comparability assessments for biosimilar and copy biologic products to ensure therapeutic equivalence.

2.4. Identifiers

Key identifiers for Tenecteplase are:

• DrugBank ID: DB00031 [1]
• CAS Number: 191588-94-0 [2]

Table 1: Tenecteplase - Key Identifiers and Properties

Property	Detail	Reference(s)
Generic Name	Tenecteplase	1
DrugBank ID	DB00031	1
CAS Number	191588-94-0	2
Type	Biotech	1
Molecular Description	Glycoprotein, 527 amino acids	1
Key Amino Acid Modifications	T103N, N117Q, KHRR296-299AAAA	1
Key Brand Names	TNKase, Metalyse, Elaxim	1
Originator/Key Developers	Genentech, Boehringer Ingelheim	3

3. Mechanism of Action

3.1. Fibrin-Specific Plasminogen Activation

Tenecteplase functions as a serine protease, exerting its thrombolytic effect by catalyzing the conversion of plasminogen, an inactive zymogen, into its active enzymatic form, plasmin.[1] A distinguishing characteristic of Tenecteplase is its high affinity for fibrin, a key protein component of blood clots. This affinity ensures that Tenecteplase preferentially binds to fibrin within a thrombus, thereby localizing its enzymatic activity to the site where clot dissolution is required.[1] The presence of fibrin markedly enhances the catalytic efficiency of Tenecteplase in converting plasminogen to plasmin, relative to its activity in the absence of fibrin.[4] This fibrin-specificity is a critical design feature, as it aims to minimize the systemic activation of plasminogen and the consequent degradation of circulating fibrinogen and other coagulation factors. Theoretically, this targeted action reduces the risk of systemic bleeding complications often associated with less specific thrombolytic agents.[4]

3.2. Enzymatic Cascade Leading to Fibrinolysis

The fibrinolytic process initiated by Tenecteplase follows a well-defined enzymatic cascade:

1. Binding to Fibrin: Tenecteplase circulates in the plasma and, upon reaching a thrombus, binds with high affinity to the fibrin meshwork of the clot.[1]
2. Plasminogen Conversion: Once bound to fibrin, Tenecteplase enzymatically cleaves the Arg561-Val562 peptide bond within the plasminogen molecule, converting it to the active serine protease, plasmin.[1]
3. Fibrin Degradation: Plasmin then acts non-specifically to degrade the fibrin polymers that form the structural matrix of the thrombus. This degradation breaks the clot into smaller, soluble fibrin degradation products.[1]
4. Clot Dissolution and Reperfusion: The enzymatic breakdown of the fibrin matrix leads to the dissolution of the thrombus, with the therapeutic goal of restoring blood flow through the previously occluded blood vessel.[4]

An additional layer of complexity and efficiency is introduced by plasmin itself, which can further potentiate Tenecteplase activity. Plasmin can cleave the single-chain form of Tenecteplase into a two-chain form, which is reported to have enhanced fibrinolytic activity at the clot site, creating a localized positive feedback loop.[5]

3.3. Impact of Molecular Modifications on Fibrin Specificity, PAI-1 Resistance, and Half-life

The specific amino acid modifications engineered into the Tenecteplase molecule are directly responsible for its distinct pharmacological advantages over native tPA or alteplase:

• Enhanced Fibrin Specificity: The substitution of the amino acid sequence Lysine-Histidine-Arginine-Arginine (KHRR) at positions 296-299 in the protease domain with a tetra-alanine sequence (AAAA) is the primary structural change responsible for Tenecteplase's approximately 14- to 15-fold increase in fibrin specificity compared to alteplase.[2] This modification alters the enzyme's conformation in such a way that its catalytic activity is more efficiently directed towards fibrin-bound plasminogen.
• Increased PAI-1 Resistance: The same KHRR→AAAA modification in the protease domain also confers a significantly greater resistance to inactivation by Plasminogen Activator Inhibitor-1 (PAI-1). PAI-1 is the principal physiological inhibitor of tPAs, and Tenecteplase exhibits an approximately 80-fold greater resistance to PAI-1 compared to alteplase.[2] This increased resistance allows Tenecteplase to remain enzymatically active for a longer duration at the site of the thrombus, contributing to more effective clot lysis.
• Prolonged Half-life: The amino acid substitutions at position T103N (Threonine to Asparagine) and N117Q (Asparagine to Glutamine) affect the molecule's N-glycosylation pattern. Specifically, T103N introduces a new consensus sequence for N-glycosylation, while N117Q (located in the Kringle 1 domain) removes an existing one.[1] These alterations in glycosylation lead to a reduction in plasma clearance, primarily by decreasing its rate of hepatic uptake and degradation. The result is a significantly prolonged plasma half-life for Tenecteplase (initial half-life of approximately 17-24 minutes, terminal phase half-life of 90-130 minutes) compared to alteplase.[2] This extended half-life is the key pharmacokinetic property that enables its convenient and rapid administration as a single intravenous bolus.

The combination of enhanced fibrin specificity and PAI-1 resistance results in a more targeted and sustained thrombolytic action. This suggests that Tenecteplase can achieve effective clot lysis with potentially less systemic activation of the fibrinolytic system, which could translate to a more favorable benefit-risk profile, particularly concerning systemic bleeding complications, although the risk of intracranial hemorrhage remains a significant concern. The cleavage of single-chain Tenecteplase to a two-chain form by plasmin at the clot site implies a localized positive feedback mechanism, potentially accelerating the thrombolysis process once initiated.

4. Pharmacodynamic Properties

4.1. Thrombolytic Effects and Markers of Fibrinolysis

The primary pharmacodynamic effect of Tenecteplase is thrombolysis, the dissolution of fibrin clots. Clinically, this is assessed by the restoration of blood flow in occluded arteries. In the context of STEMI, this is often measured by improvements in coronary artery patency, such as achieving TIMI (Thrombolysis In Myocardial Infarction) grade 3 flow.[13] In AIS, successful thrombolysis is indicated by reperfusion or recanalization of occluded cerebral arteries.

Systemically, the administration of Tenecteplase leads to measurable changes in markers of fibrinolysis. Therapeutic doses (e.g., 30 mg, 40 mg, or 50 mg in STEMI patients) typically result in modest decreases in the plasma concentrations of circulating fibrinogen (approximately 4% to 15%) and plasminogen (approximately 11% to 24%).[4] These reductions reflect some degree of systemic fibrinolytic activation, although less pronounced than with older, less fibrin-specific agents. The time course of these effects is generally correlated with the drug's pharmacokinetic profile and duration of action.

4.2. Comparative Pharmacodynamics with Alteplase

Tenecteplase exhibits key pharmacodynamic differences when compared to alteplase. It possesses a significantly higher fibrin specificity (approximately 14- to 15-fold greater) and a markedly increased resistance to inhibition by PAI-1 (approximately 80-fold greater).[2] This enhanced fibrin specificity means that Tenecteplase is more efficient at activating plasminogen that is bound to fibrin within a clot, as opposed to free plasminogen circulating in the plasma. Consequently, at equipotent thrombolytic doses, Tenecteplase generally causes less systemic activation of the fibrinolytic system and, therefore, less degradation of circulating fibrinogen than alteplase.[4] While the direct clinical translation of this difference to overall safety outcomes, particularly major bleeding events, is influenced by multiple factors, it represents a fundamental pharmacodynamic advantage of Tenecteplase.

The relatively small reduction in systemic fibrinogen observed with Tenecteplase, despite its potent clot-lysing activity, serves as a pharmacodynamic validation of its engineered fibrin-specificity.[4] This characteristic suggests a better preservation of systemic hemostatic capacity during therapy, which could contribute to a lower incidence of certain types of systemic bleeding complications. However, it is crucial to note that local bleeding at sites of vascular injury and the risk of intracranial hemorrhage remain inherent concerns with any potent thrombolytic agent. The pharmacodynamic profile, characterized by high fibrin specificity and PAI-1 resistance, directly supports the pharmacokinetic advantage of a longer effective half-life. This synergy allows the single-bolus administration to be effective, as the drug can reach the clot, bind effectively, resist rapid inactivation by PAI-1, and exert its lytic effect over a clinically meaningful period.

5. Pharmacokinetic Profile

5.1. Absorption and Distribution (Volume of Distribution)

Tenecteplase is administered exclusively by the intravenous (IV) route, typically as a single, rapid bolus injection over 5 seconds.[3] This method ensures immediate and complete (100%) bioavailability in the systemic circulation. Following IV administration, Tenecteplase exhibits a multi-phasic disposition from the plasma. The initial volume of distribution (Vc or V1), representing distribution primarily within the plasma volume, is weight-dependent and has been reported in ranges such as 4.2 to 5.4 L (according to the FDA label) or 3.1 to 6.3 L (according to the TNKase EU SPC).[2] The volume of distribution at steady-state (Vss) is larger, estimated to be between 6.1 to 8.01 L (FDA label) or 6.1 to 9.9 L (EU SPC), suggesting some limited distribution into extravascular compartments.[2]

5.2. Metabolism (Primary Hepatic) and Elimination

The primary route of clearance for Tenecteplase from the circulation is hepatic metabolism.[2] The molecule is taken up by specific receptors in the liver and subsequently catabolized into smaller, inactive peptides.[2] Renal excretion of unchanged Tenecteplase is minimal, indicating that kidney function has a limited direct impact on its elimination.[2]

5.3. Half-life and Clearance

Tenecteplase exhibits a biphasic elimination pattern from the plasma. The dominant initial phase half-life (t½α), reflecting distribution and early elimination, is approximately 17 to 24 minutes.[2] The terminal phase half-life (t½β), which is more indicative of the drug's overall persistence, is considerably longer, reported to be in the range of 90 to 130 minutes.[2] This prolonged terminal half-life, relative to that of alteplase, is a key pharmacokinetic feature that underpins its suitability for single-bolus administration. The plasma clearance of Tenecteplase in patients with acute myocardial infarction typically ranges from 98 to 119 mL/min.[1] Pharmacokinetic studies have demonstrated that Tenecteplase exhibits linear pharmacokinetics across the clinically relevant dose range of 30 mg to 50 mg, meaning that increases in dose result in proportional increases in plasma concentrations and exposure.[4]

The pharmacokinetic profile of Tenecteplase, characterized by an initial distribution phase followed by a slower elimination phase driven primarily by hepatic metabolism, is consistent with that of a recombinant glycoprotein of its molecular size. The molecular modifications engineered into Tenecteplase successfully retarded its clearance mechanisms, as evidenced by its longer half-life compared to native tPA or alteplase. This prolongation is the cornerstone of its significant clinical advantage of single-bolus administration. The linearity of its pharmacokinetics across the therapeutic dose range further simplifies dosing regimens and ensures predictable drug exposure, which is highly beneficial in emergency medical situations where complex dose adjustments are impractical and rapid, reliable drug action is essential.

6. Clinical Efficacy in Approved and Investigational Indications

6.1. Acute Myocardial Infarction (STEMI)

Tenecteplase is a well-established thrombolytic agent for the treatment of STEMI, aiming to achieve rapid reperfusion of occluded coronary arteries, thereby reducing infarct size, preserving myocardial function, and decreasing mortality.[3] It is recommended for administration as soon as possible after the onset of STEMI symptoms.[4]

Summary of Pivotal Trials:

Several large-scale clinical trials have defined the role of Tenecteplase in STEMI:

• ASSENT-2 (Assessment of the Safety and Efficacy of a New Thrombolytic-2): This landmark trial randomized 16,949 patients with STEMI to receive either a single, weight-adjusted bolus of Tenecteplase or an accelerated (front-loaded) infusion of alteplase.[6] The primary endpoint, 30-day mortality, was equivalent between the two groups (6.2% for both Tenecteplase and alteplase). This equivalence in mortality persisted at the 1-year follow-up (9.2% for Tenecteplase vs. 9.1% for alteplase).[15] Importantly, Tenecteplase was associated with a significantly lower incidence of noncerebral bleeding complications and a reduced need for blood transfusions compared to alteplase.[6]
• ASSENT-3 (Assessment of the Safety and Efficacy of a New Thrombolytic-3): This trial enrolled 6,095 STEMI patients to evaluate Tenecteplase in combination with different antithrombotic regimens: full-dose Tenecteplase with enoxaparin, half-dose Tenecteplase with weight-adjusted low-dose unfractionated heparin (UFH) and abciximab, or full-dose Tenecteplase with weight-adjusted UFH.[16] The combination of full-dose Tenecteplase and enoxaparin resulted in significantly fewer ischemic complications (a composite of 30-day mortality, in-hospital reinfarction, or in-hospital refractory ischemia) compared to Tenecteplase plus UFH (11.4% vs. 15.4%, respectively). The 30-day mortality rate was lowest in the enoxaparin group (5.4%). The half-dose Tenecteplase plus abciximab regimen also showed improved efficacy over UFH but was associated with an increased risk of major hemorrhage, particularly in patients older than 75 years.[17]
• TIMI 10B (Thrombolysis In Myocardial Infarction 10B): This angiographic study compared various doses of Tenecteplase (30 mg, 40 mg, and 50 mg) with front-loaded alteplase in 886 STEMI patients.[13] The 40 mg dose of Tenecteplase achieved a rate of TIMI grade 3 flow (complete perfusion) at 90 minutes that was similar to that achieved with alteplase (62.8% vs. 62.7%, respectively). The trial highlighted the importance of weight-adjusted dosing for Tenecteplase and suggested that modifications to heparin dosing could enhance the safety profile of both thrombolytic agents.[13]

The consistent demonstration of non-inferiority to alteplase in terms of mortality in STEMI, combined with the significant practical advantage of single-bolus dosing and a trend towards fewer non-cerebral bleeding events (as seen in ASSENT-2), rapidly established Tenecteplase as a preferred thrombolytic agent in many STEMI treatment protocols. The ASSENT-3 trial further refined its application by exploring optimal concomitant antithrombotic therapies, underscoring the potential benefits of enoxaparin in this setting.

Table 2: Summary of Major Clinical Trials of Tenecteplase in Acute Myocardial Infarction (STEMI)

Trial Name	Comparator(s)	Patient Population	Key Efficacy Endpoints	Key Safety Endpoints (vs. Alteplase/UFH)	Summary of Results	Snippet ID(s)
ASSENT-2	Alteplase (accelerated infusion)	16,949 STEMI patients	30-day mortality; 1-year mortality	ICH (similar); Non-cerebral bleeding (lower with TNK); Blood transfusions (fewer with TNK)	Equivalent 30-day and 1-year mortality. Tenecteplase associated with fewer non-cerebral bleeding complications and less need for blood transfusions.	6
ASSENT-3	Tenecteplase + UFH; Tenecteplase + Abciximab	6,095 STEMI patients	30-day mortality, in-hospital reinfarction, or in-hospital refractory ischemia (composite)	Major hemorrhage (TNK+Enox vs TNK+UFH: similar; TNK+Abci vs TNK+UFH: higher)	Tenecteplase + Enoxaparin significantly reduced ischemic complications and had the lowest 30-day mortality (5.4%) vs. TNK+UFH. TNK+Abciximab also reduced ischemic events but increased major bleeding, especially in elderly.	16
TIMI 10B	Alteplase (front-loaded)	886 STEMI patients	TIMI grade 3 flow at 90 minutes	ICH, Serious bleeding (rates improved with lower heparin doses for both)	40 mg Tenecteplase achieved similar TIMI grade 3 flow to alteplase. Emphasized importance of weight-adjusted TNK dosing and optimized heparin regimen.	13

6.2. Acute Ischemic Stroke (AIS)

Tenecteplase has emerged as an important therapeutic option for AIS, receiving FDA approval for this indication in March 2025.[3] Treatment is generally recommended to be initiated as soon as possible, typically within 3 to 4.5 hours of symptom onset, although research into extended time windows is ongoing.[3]

Summary of Key Trials:

• AcT (Alteplase compared to Tenecteplase): This large, multi-center, investigator-initiated non-inferiority trial conducted in Canada compared Tenecteplase (0.25 mg/kg, max 25 mg) to alteplase in AIS patients with disabling neurological deficits.[3] The results demonstrated comparable safety and efficacy between Tenecteplase and alteplase, forming a key part of the evidence supporting the FDA approval of Tenecteplase for AIS.
• ATTEST & ATTEST-2: The ATTEST trial, a phase 2 study, found no significant difference in the percentage of penumbra salvaged between Tenecteplase (0.25 mg/kg) and alteplase in patients treated within 4.5 hours.[19] The subsequent ATTEST-2 phase 3 trial, conducted in the UK, showed that Tenecteplase (0.25 mg/kg) was non-inferior to alteplase (0.9 mg/kg) for the primary outcome of modified Rankin Scale (mRS) score distribution at 90 days when administered within 4.5 hours of stroke onset. However, superiority was not demonstrated. Safety outcomes, including symptomatic intracranial hemorrhage (sICH) and mortality, were similar between the groups.[20]
• NOR-TEST & NOR-TEST 2 (Part A): The initial NOR-TEST trial compared Tenecteplase (0.4 mg/kg) with alteplase and found similar efficacy and safety outcomes, though a high proportion of patients had mild strokes.[21] In a subgroup analysis of patients with moderate to severe stroke from NOR-TEST, Tenecteplase 0.4 mg/kg was associated with increased 90-day mortality.[21] NOR-TEST 2 (Part A) specifically evaluated Tenecteplase 0.4 mg/kg versus alteplase in patients with moderate or severe ischemic stroke. This part of the trial was stopped prematurely due to safety concerns, as an imbalance in sICH rates and higher mortality were observed in the Tenecteplase 0.4 mg/kg group.[22] Part B of NOR-TEST 2 is ongoing, evaluating a lower dose of Tenecteplase (0.25 mg/kg).
• EXTEND-IA TNK & ATTENTION-IA: The EXTEND-IA TNK trial program has explored Tenecteplase in the context of endovascular thrombectomy (EVT). One analysis involving patients from EXTEND-IA TNK Parts 1 and 2, and SWIFT DIRECT, found that intravenous Tenecteplase (0.25 mg/kg or 0.40 mg/kg) administered prior to thrombectomy did not significantly increase the rate of functional independence (mRS 0-1) but did result in a significant improvement in the overall distribution of mRS scores at 90 days compared to thrombectomy alone.[23] The ATTENTION-IA trial investigated intra-arterial Tenecteplase administered after successful endovascular recanalization in patients with acute posterior circulation arterial occlusion; it did not demonstrate a statistically significant reduction in combined disability and mortality at 90 days.[24]
• TIMELESS (Tenecteplase in Stroke Patients Between 4.5 and 24 Hours): This trial evaluated Tenecteplase (0.25 mg/kg) versus placebo in patients with AIS due to large vessel occlusion presenting in an extended time window (4.5 to 24 hours after last known well) and selected based on favorable perfusion imaging.[25] The majority of patients (77%) also underwent EVT. The trial found that Tenecteplase did not significantly improve the 90-day mRS score distribution or functional independence compared to placebo in this late-window, EVT-eligible population, although it did increase reperfusion rates.[25]
• TRACE-2 (Tenecteplase Reperfusion therapy in Acute ischaemic Cerebrovascular Events-2): Conducted in China, this phase 3 trial randomized patients with AIS within 4.5 hours of symptom onset, who were ineligible for EVT, to receive either Tenecteplase (0.25 mg/kg) or alteplase.[27] TRACE-2 demonstrated that Tenecteplase was non-inferior to alteplase, with similar proportions of patients achieving an excellent functional outcome (mRS 0-1 at 90 days) and comparable safety profiles, including rates of sICH and mortality.
• TASTE & ORIGINAL: The TASTE trial, which selected patients within 4.5 hours using perfusion imaging, found that Tenecteplase (0.25 mg/kg) narrowly missed demonstrating non-inferiority to alteplase in the intention-to-treat analysis for mRS 0-1 at 90 days, but non-inferiority was met in the per-protocol analysis. Safety outcomes were comparable.[29] The ORIGINAL trial, conducted in a Chinese cohort within 4.5 hours, showed Tenecteplase (0.25 mg/kg) to be non-inferior to alteplase for achieving mRS 0-1 at 90 days, with similar safety.[29]
• ANGEL-TNK & PEARL: These trials investigated the utility of intra-arterial thrombolysis after successful EVT. ANGEL-TNK (using tenecteplase) and PEARL (using alteplase) both suggested that adjunctive intra-arterial administration of the lytic agent increased the proportion of patients achieving an excellent neurological outcome (mRS 0-1) at 90 days compared to standard medical treatment alone.[31]

The journey of Tenecteplase in AIS treatment has been characterized by extensive research. While non-inferiority to alteplase is a recurrent theme in trials utilizing the 0.25 mg/kg dose within the 4.5-hour window, the optimal dose has been a point of investigation, with the 0.4 mg/kg dose raising safety concerns in some AIS populations (e.g., NOR-TEST 2). The simpler administration protocol of Tenecteplase remains a significant practical advantage, driving its adoption.

The efficacy of Tenecteplase in the late window (4.5-24 hours) and as an adjunct to EVT is an actively evolving field. Trials like TIMELESS did not show a benefit for IV Tenecteplase in the late window when EVT was prevalent, whereas other data (e.g., TRACE-III video summary 32) suggested potential benefit in settings without widespread EVT access. The role of intra-arterial lytics post-EVT, as explored in ANGEL-TNK and PEARL, suggests a different niche, potentially for addressing distal or microvascular thrombi, though ATTENTION-IA in posterior circulation did not yield statistically significant positive results. This indicates that patient selection criteria, including access to EVT and the specific location of the occlusion, are critical variables influencing outcomes.

Table 3: Summary of Major Clinical Trials of Tenecteplase in Acute Ischemic Stroke (AIS)

Trial Name	TNK Dose (mg/kg)	Comparator	Time Window (hrs)	Patient Population Highlights	Key Efficacy Endpoint (90-day mRS)	Key Safety Endpoint (sICH) (TNK vs Comp)	Summary of Results	Snippet ID(s)
AcT	0.25	Alteplase	<4.5	Disabling neurological deficit	Comparable (non-inferiority met)	Comparable	Supported FDA approval; Tenecteplase comparable to alteplase in safety and efficacy.	3
ATTEST-2	0.25	Alteplase	<4.5	General AIS	Non-inferior for mRS distribution (not superior)	2% vs 2%	Tenecteplase 0.25 mg/kg non-inferior to alteplase; similar safety. Suggests TNK preferred due to easier administration.	20
NOR-TEST 2 (A)	0.4	Alteplase	<4.5	Moderate or severe stroke	Worse functional outcome (unadjusted OR 0.45)	6% vs 1% (sICH); 21% vs 7% (any ICH)	Trial stopped early due to higher ICH and mortality with 0.4 mg/kg Tenecteplase. Did not show non-inferiority.	22
TIMELESS	0.25	Placebo	4.5-24	LVO, favorable perfusion imaging, 77% received EVT	No significant improvement in median mRS (3 vs 3) or mRS ≤2 (46% vs 42.4%)	3.2% vs 2.3%	Tenecteplase did not improve 90-day neurological outcomes in late window with LVO and EVT. Increased reperfusion but no clinical benefit.	25
TRACE-2	0.25	Alteplase	<4.5	AIS, ineligible for EVT (China)	Non-inferior for mRS 0-1 (62% vs 58%)	2% vs 2%	Tenecteplase non-inferior to alteplase in AIS patients ineligible for EVT; similar safety.	27
EXTEND-IA TNK (IV Bridging)	0.25 or 0.4	Thrombectomy alone	N/A (pre-EVT)	AIS, LVO	No significant increase in mRS 0-1; significant improvement in overall mRS distribution (acOR 1.56)	Not directly compared for sICH in snippet	IV Tenecteplase before EVT improved overall mRS distribution.	23
ANGEL-TNK (IA)	Varied	Standard Med Rx	Post-EVT	AIS, LVO, successful EVT (eTICI 2b50-3)	Higher mRS 0-1 (40.5% vs 26.4%)	5.6% vs 6.2%	Intra-arterial Tenecteplase after EVT increased proportion of patients with excellent neurological outcome.	31
ATTENTION-IA (IA)	0.0625 (max 6.25mg)	EVT only	Post-EVT	Posterior circulation LVO, successful recanalization	No significant reduction in mRS 0-1 (34.6% vs 26.0%)	8.3% vs 3.1%	Intra-arterial Tenecteplase after EVT in posterior circulation stroke did not significantly reduce disability/mortality.	24
TASTE	0.25	Alteplase	<4.5	AIS, perfusion imaging selected	Numerically higher mRS 0-1 (57% vs 55.3%), narrowly missed non-inferiority (ITT), met in per-protocol	Comparable	Results support Tenecteplase use, in line with previous trials.	29
ORIGINAL	0.25	Alteplase	<4.5	AIS (China)	Non-inferior for mRS 0-1 (72.7% vs 70.3%)	1.2% vs 1.2%	Tenecteplase non-inferior to alteplase in Chinese AIS patients; similar safety.	29

Note: mRS = modified Rankin Scale; sICH = symptomatic Intracranial Hemorrhage; LVO = Large Vessel Occlusion; EVT = Endovascular Thrombectomy; IA = Intra-arterial; IV = Intravenous; Comp = Comparator; TNK = Tenecteplase; Med Rx = Medical Treatment; acOR = adjusted common Odds Ratio.

6.3. Pulmonary Embolism (PE)

Tenecteplase is listed as an agent for pulmonary emboli in its DrugBank summary.[1] Clinical guidelines generally recommend systemic fibrinolysis for patients with high-risk (massive) PE, characterized by hemodynamic instability.[33] For patients with intermediate-risk (submassive) PE, the role of systemic thrombolysis is more controversial due to the balance between potential benefits (e.g., prevention of hemodynamic decompensation) and risks (e.g., major bleeding). A meta-analysis focusing on Tenecteplase in PE indicated that for intermediate-risk patients, Tenecteplase could reduce the risk of hemodynamic decompensation but was associated with a high bleeding risk.[34] The same analysis suggested that catheter-directed thrombolysis with low-dose Tenecteplase might offer a more favorable benefit-risk profile in selected intermediate-risk PE patients.[34] Current general PE guidelines do not typically single out Tenecteplase over other approved thrombolytics but emphasize careful risk stratification.[33]

6.4. Catheter Occlusion

Thrombotic occlusion of central venous catheters (CVCs) is a common complication that can impede the delivery of essential therapies.[35] Thrombolytic agents are often used to restore catheter patency. The TROPICS-2 (ThROmbolysis for PICS-2) trial, a phase III, open-label, single-arm study, was designed to evaluate the safety and efficacy of Tenecteplase in restoring function to occluded non-hemodialysis CVCs in both pediatric and adult subjects.[36] In this trial, Tenecteplase was instilled intraluminally at a dose of up to 2 mg (in 2 mL) or 110% of the internal lumen volume for subjects weighing <30 kg. The primary efficacy endpoint was the restoration of CVC function (ability to withdraw blood and infuse saline) within 120 minutes after a single administration of Tenecteplase. While the detailed results of TROPICS-2 are not provided in the available material, this trial indicates an effort to establish Tenecteplase for this common clinical problem, leveraging its known fibrinolytic mechanism in a localized application.[36]

The evidence for Tenecteplase in PE suggests a cautious approach, particularly for intermediate-risk patients, due to bleeding concerns, with catheter-directed low-dose therapy emerging as a potentially safer alternative. For catheter occlusion, Tenecteplase offers a similar mechanistic approach to other tPAs, and the TROPICS-2 trial aims to provide specific evidence for its use in this setting.

7. Safety and Tolerability Profile

7.1. Common and Serious Adverse Events (Detailed focus on bleeding events, including Intracranial Hemorrhage)

The most significant and common adverse event associated with Tenecteplase therapy, across all its indications, is bleeding.[3] This can manifest as internal bleeding (e.g., intracranial, retroperitoneal, gastrointestinal, genitourinary) or external/superficial bleeding, particularly at arterial and venous puncture sites, recent surgical sites, or sites of trauma.[4]

Intracranial Hemorrhage (ICH) is the most feared bleeding complication.

• In STEMI trials:
• ASSENT-2 reported similar rates of ICH for Tenecteplase and alteplase.[6]
• ASSENT-3 PLUS showed higher rates of ICH with the Tenecteplase-enoxaparin combination in certain subgroups (e.g., women older than 75 years) compared to Tenecteplase-UFH.[16]
• In AIS trials:
• AcT: Comparable safety, including ICH, to alteplase.[3]
• ATTEST-2 (0.25 mg/kg): sICH rates were 2% for Tenecteplase vs. 2% for alteplase.[20]
• NOR-TEST 2, Part A (0.4 mg/kg): sICH was 6% with Tenecteplase vs. 1% with alteplase; any ICH was 21% vs. 7%.[22] This trial was stopped early due to these safety concerns.
• TIMELESS (0.25 mg/kg, late window): sICH rates were 3.2% for Tenecteplase vs. 2.3% for placebo.[26]
• TRACE-2 (0.25 mg/kg): sICH rates were 2% for Tenecteplase vs. 2% for alteplase.[28]
• ORIGINAL (0.25 mg/kg): sICH rates were 1.2% for Tenecteplase vs. 1.2% for alteplase.[30]

While Tenecteplase was engineered for enhanced fibrin specificity with the aim of potentially reducing systemic bleeding relative to older thrombolytics, the risk of bleeding, especially ICH, remains a primary safety concern. This risk is a critical factor in the careful benefit-risk assessment required for each patient. Data from STEMI trials like ASSENT-2 suggested a potential advantage in non-cerebral bleeding compared to alteplase.[6] However, in the context of AIS, ICH rates with the 0.25 mg/kg dose are generally comparable to alteplase, as seen in ATTEST-2, TRACE-2, and ORIGINAL.[20] The concerning safety signal with the 0.4 mg/kg dose in the NOR-TEST 2 trial [22] underscores that fibrin specificity does not eliminate the risk of ICH, and dose optimization is crucial for different indications.

7.2. Hypersensitivity Reactions, Cholesterol Embolization, Arrhythmias

Other clinically significant adverse reactions reported with Tenecteplase include:

• Hypersensitivity Reactions: These can range from rash and urticaria to more severe manifestations like angioedema, laryngeal edema, and anaphylaxis.[4] Patients should be monitored during and after administration, and appropriate therapy initiated if symptoms occur.
• Cholesterol Embolization: This is a rare but serious complication reported in patients treated with all thrombolytic agents, including Tenecteplase. It involves the dislodgement of cholesterol crystals from atherosclerotic plaques, which can embolize to various organs.[4]
• Arrhythmias: Coronary thrombolysis can result in reperfusion arrhythmias, such as sinus bradycardia, accelerated idioventricular rhythm, ventricular premature depolarizations, and ventricular tachycardia. Standard anti-arrhythmic therapy should be available.[4]

7.3. Contraindications

Tenecteplase is contraindicated in several situations due to the high risk of life-threatening bleeding [4]:

• Active internal bleeding.
• History of cerebrovascular accident (for STEMI indication; this is nuanced for AIS treatment itself).
• Recent (e.g., within 2-3 months) intracranial or intraspinal surgery or serious head trauma.
• Presence of intracranial conditions that increase the risk of bleeding (e.g., neoplasm, arteriovenous malformation, aneurysm).
• Known bleeding diathesis or current severe uncontrolled hypertension.
• For AIS treatment specifically: current intracranial hemorrhage.
• For STEMI treatment specifically: history of intracranial hemorrhage.

The contraindications underscore the necessity of meticulous patient selection to optimize the safety of Tenecteplase therapy. Factors such as recent surgery, uncontrolled hypertension, or a prior history of ICH are critical exclusion criteria.

7.4. Warnings and Precautions

Several warnings and precautions are associated with Tenecteplase use:

• Bleeding: The most common risk. Concomitant use of other drugs that impair hemostasis (e.g., anticoagulants, antiplatelet agents) significantly increases this risk. Intramuscular injections and unnecessary patient handling should be avoided.[4]
• Thromboembolism: The use of thrombolytics can paradoxically increase the risk of thromboembolic events in patients with a high likelihood of left heart thrombus (e.g., mitral stenosis, atrial fibrillation).[4]
• Increased Risk of Heart Failure and Recurrent Ischemia with Planned PCI in STEMI: If Tenecteplase is used as a pharmacoinvasive strategy before planned PCI in STEMI, there may be an increased risk of these complications.[4]
• Blood Pressure Monitoring in AIS: During and following Tenecteplase administration for AIS, blood pressure must be frequently monitored and controlled.[4]

7.5. Drug Interactions (Emphasis on anticoagulants, antiplatelet agents, and dextrose incompatibility)

Tenecteplase has several clinically significant drug interactions:

• Anticoagulants and Antiplatelet Agents: The concomitant use of anticoagulants (e.g., heparin, warfarin, direct oral anticoagulants like apixaban, dabigatran, rivaroxaban) or antiplatelet drugs (e.g., aspirin, clopidogrel, ticagrelor, GPIIb/IIIa inhibitors) with Tenecteplase markedly increases the risk of bleeding. Careful monitoring and risk-benefit assessment are essential if co-administration is necessary.[1]
• Dextrose Incompatibility: Tenecteplase is chemically incompatible with dextrose-containing solutions. Mixing or co-administering Tenecteplase through the same IV line as dextrose solutions can lead to precipitation of the drug, potentially reducing its efficacy and causing harm. Dextrose-containing lines must be flushed thoroughly with a 0.9% Sodium Chloride Injection, USP, solution before and after Tenecteplase administration.[4] This practical administration detail, if overlooked, could lead to significant therapeutic failure or adverse events.
• Effects on Coagulation Tests: Tenecteplase is an enzyme that remains active in blood samples drawn for coagulation tests. This can lead to in vitro degradation of fibrinogen and other clotting factors, potentially yielding unreliable test results unless specific precautions (e.g., use of specific collection tubes with inhibitors) are taken to prevent these artifacts.[4]

Table 4: Clinically Significant Drug Interactions with Tenecteplase

Interacting Drug/Class	Nature of Interaction	Management/Recommendation	Snippet ID(s)
Anticoagulants (e.g., Heparin, Warfarin, DOACs)	Increased risk of bleeding	Avoid concomitant use if possible; if necessary, monitor closely for bleeding. Adjust doses of anticoagulants as appropriate.	1
Antiplatelet Agents (e.g., Aspirin, Clopidogrel, Ticagrelor)	Increased risk of bleeding	Avoid concomitant use if possible, especially high doses or multiple agents. If necessary, monitor closely for bleeding.	1
Nonsteroidal Anti-inflammatory Drugs (NSAIDs)	Increased risk of bleeding (due to antiplatelet effects and potential GI toxicity)	Use with caution; monitor for GI bleeding.	18
Dextrose-containing Solutions	Chemical incompatibility, precipitation of Tenecteplase	Do not mix Tenecteplase with dextrose solutions. Flush IV lines containing dextrose with 0.9% Sodium Chloride Injection before and after Tenecteplase administration.	4
Other Thrombolytics (e.g., alteplase, reteplase)	Increased risk of bleeding due to synergistic thrombolytic effects	Concomitant use generally not recommended.	18
Drugs that affect coagulation tests in vitro	Potential for unreliable test results due to in vitro fibrinogenolysis by Tenecteplase	Use appropriate sample collection and handling procedures (e.g., tubes with protease inhibitors) if coagulation monitoring is required during or shortly after Tenecteplase administration.	4

8. Dosage, Administration, and Reconstitution

8.1. Recommended Dosing Regimens for STEMI and AIS (Weight-based)

The dosing of Tenecteplase is weight-based and differs between its approved indications of STEMI and AIS.

• For Acute ST Elevation Myocardial Infarction (STEMI): Tenecteplase is administered as a single intravenous bolus over 5 seconds. The dose is tiered according to patient weight, with a maximum recommended dose of 50 mg.4 The specific weight-based dosing is detailed in Table 5.
• For Acute Ischemic Stroke (AIS): Similarly, for AIS, Tenecteplase is administered as a single intravenous bolus over 5 seconds. The treatment should be initiated as soon as possible and within 3 hours after the onset of stroke symptoms. The dosage is also weight-tiered, but the maximum recommended dose for AIS is 25 mg.4 The specific weight-based dosing is detailed in Table 5.

The weight-based dosing regimen is a critical aspect for optimizing the balance between therapeutic efficacy and the risk of adverse events, particularly bleeding. The established maximum dose caps (50 mg for STEMI and 25 mg for AIS) serve as important safety parameters, especially for patients at higher body weights. The lower maximum dose for AIS likely reflects a different therapeutic window and risk-benefit consideration in stroke patients, who may have a higher baseline risk of ICH, or differing clot characteristics compared to coronary thrombi. The TIMI 10B trial had previously emphasized the importance of weight-adjustment for Tenecteplase in STEMI.[13]

Table 5: Recommended Dosage of Tenecteplase (TNKase®) for Approved Indications

Indication	Patient Weight (kg)	TNKase® Dose (mg)	Volume to Administer (mL) of Reconstituted Solution (5 mg/mL)
STEMI	< 60	30	6
	60 to < 70	35	7
	70 to < 80	40	8
	80 to < 90	45	9
	≥ 90	50	10
AIS	< 60	15	3
	60 to < 70	17.5	3.5
	70 to < 80	20	4
	80 to < 90	22.5	4.5
	≥ 90	25	5

Source: Adapted from TNKase® Prescribing Information.[4]

8.2. Preparation, Reconstitution, and Intravenous Bolus Administration

Proper preparation and administration are crucial for the safety and efficacy of Tenecteplase:

• Reconstitution: Tenecteplase is supplied as a lyophilized powder in a single-dose vial and must be reconstituted immediately before use with the co-packaged Sterile Water for Injection, USP (diluent). The strength of the reconstituted solution is typically 5 mg/mL (e.g., 50 mg vial reconstituted with 10 mL SWFI, or 25 mg vial with 5 mL SWFI).[4] The vial should be gently swirled, not shaken, to dissolve the powder.
• Inspection: The reconstituted solution should be visually inspected for particulate matter and discoloration. It should be clear and colorless to pale yellow. If particulate matter or discoloration is observed, the solution should not be used.[4]
• Administration: The entire calculated weight-based dose is administered as a single intravenous bolus over 5 seconds.[3]
• IV Line Compatibility: Tenecteplase is incompatible with dextrose-containing solutions, as precipitation may occur. If an IV line containing dextrose is to be used, it must be flushed thoroughly with a 0.9% Sodium Chloride Injection, USP, solution before and after Tenecteplase administration.[4]
• Storage after Reconstitution: If not used immediately, the reconstituted Tenecteplase solution may be refrigerated at 2∘C to 8∘C (36∘F to 46∘F) and must be used within 8 hours.[4]

The simplicity of a single, rapid (5-second) IV bolus administration is a major practical advantage over the more complex bolus-plus-infusion regimen required for alteplase, particularly in emergency settings. This streamlined process can reduce the potential for dosing errors and save critical time in initiating thrombolytic therapy.

9. Regulatory Status and Market Availability

9.1. FDA, EMA, and Other Regulatory Approvals

Tenecteplase has received regulatory approval in numerous countries worldwide for its primary indications.

• U.S. Food and Drug Administration (FDA):
• Initially approved for the reduction of mortality associated with acute ST-elevation myocardial infarction (STEMI) under the brand name TNKase®.[3]
• In March 2025, the FDA expanded the approval of TNKase® to include the treatment of acute ischemic stroke (AIS) in adults.[3]
• European Medicines Agency (EMA):
• Approved for the treatment of STEMI under the brand name Metalyse®.[5] The approval status for AIS in the EU is not explicitly detailed in the provided materials, but clinical trials such as ATTEST-2 have been conducted in Europe, suggesting active investigation and potential future submissions for this indication.
• Other Regions:
• Canada: Approved as TNKase® for STEMI and likely AIS following US approval.[3]
• China: A copy version, Mingfule®, is approved for STEMI and AIS.[5]
• India: A biosimilar, Elaxim®, is available.[10]

The recent FDA approval for AIS in March 2025 represents a significant development, positioning Tenecteplase as an alternative to alteplase, which had long been the sole FDA-approved thrombolytic for this indication. This expansion is likely to influence stroke treatment guidelines and clinical practice, particularly given Tenecteplase's administrative advantages.

9.2. Key Brand Names (TNKase, Metalyse, Elaxim, Mingfule) and Manufacturers/Developers (Genentech, Boehringer Ingelheim, Roche, etc.)

The development and marketing of Tenecteplase involve several pharmaceutical companies globally:

• TNKase®: Developed and marketed by Genentech, a member of the Roche Group, in the United States and Canada.[1]
• Metalyse®: Marketed by Boehringer Ingelheim in most countries outside of the United States, Canada, and Japan.[1]
• Elaxim®: A biosimilar version of Tenecteplase manufactured and marketed by Gennova Biopharmaceuticals Ltd. in India.[10]
• Mingfule®: A tenecteplase copy version marketed by CSPC Pharmaceutical Group in China.[5]

The existence of biosimilar and copy versions of Tenecteplase in various markets reflects the drug's established efficacy and the global demand for such life-saving therapies. However, it is important to acknowledge that, as highlighted in studies comparing originator and copy biologics (e.g., Metalyse® vs. Mingfule® [5]), biochemical and potentially clinical differences can exist. This underscores the necessity for thorough comparability studies and stringent regulatory oversight for all versions of Tenecteplase to ensure consistent safety and efficacy for patients worldwide.

10. Discussion

10.1. Key Advantages of Tenecteplase (e.g., single-bolus administration, fibrin specificity)

Tenecteplase offers several distinct advantages over older thrombolytic agents, particularly alteplase. Its molecular engineering has resulted in a pharmacological profile characterized by:

• Single-Bolus Administration: Enabled by its longer plasma half-life, this is arguably its most significant practical advantage, simplifying and speeding up treatment initiation in emergency settings.[2]
• Greater Fibrin Specificity: Tenecteplase preferentially activates plasminogen at the site of a fibrin clot, leading to more targeted thrombolysis.[2]
• Increased PAI-1 Resistance: Its enhanced resistance to inactivation by plasminogen activator inhibitor-1 allows for more sustained fibrinolytic activity at the thrombus.[2] These properties collectively contribute to its clinical utility and have positioned it as a favorable alternative in thrombolytic therapy.

10.2. Comparative Place in Thrombolytic Therapy

In the treatment of STEMI, Tenecteplase (TNKase®, Metalyse®) rapidly became a leading thrombolytic agent following the results of trials like ASSENT-2, which demonstrated its non-inferiority to alteplase in terms of mortality, coupled with a better safety profile regarding non-cerebral bleeding and the convenience of single-bolus dosing.[6]

For AIS, alteplase was the established standard of care for decades. However, the recent FDA approval of Tenecteplase (TNKase®) for AIS, supported by trials like AcT, ATTEST-2, TRACE-2, and ORIGINAL, is shifting this paradigm.[3] While most head-to-head trials have shown non-inferiority rather than superiority in efficacy for the 0.25 mg/kg dose, the ease and speed of its single-bolus administration are compelling advantages in the time-critical context of stroke care.[3] This practical benefit is a strong driver for its increasing adoption in AIS protocols.

10.3. Unmet Needs and Future Research Directions

Despite the advancements offered by Tenecteplase, several areas warrant further investigation:

• Optimal Dosing in Severe AIS: The safety concerns raised by the NOR-TEST 2 trial with the 0.4 mg/kg dose in moderate/severe stroke highlight the need to clearly define the optimal and safe dose for this patient subgroup, with the 0.25 mg/kg dose currently favored.[22]
• Late-Window AIS and EVT Adjunctive Therapy: The role of Tenecteplase in patients presenting in extended time windows (beyond 4.5 hours) for AIS remains an area of active research. Trials like TIMELESS did not show benefit for IV Tenecteplase in this setting when EVT was readily available [25], whereas other data suggest potential utility in populations without immediate EVT access. Furthermore, the utility of intra-arterial Tenecteplase as an adjunct to EV, either as bridging therapy or for post-procedural clot dissolution, is being explored (e.g., EXTEND-IA TNK, ANGEL-TNK) with mixed but promising signals in specific contexts.[23]
• Pulmonary Embolism: While used off-label and investigated for PE, its precise role, optimal dosing, and comparative efficacy against other thrombolytics or anticoagulation strategies, particularly in intermediate-risk PE, require further clarification through dedicated large-scale trials.[34]
• Pediatric Applications: The TROPICS-2 trial investigated Tenecteplase for CVC occlusion in pediatric patients, an area where safe and effective thrombolytic options are needed.[36]
• Biosimilar/Copy Version Comparability: Continued vigilance and comparative studies are needed to ensure that biosimilar or copy versions of Tenecteplase maintain comparable efficacy and safety profiles to the originator products.[5]

The research landscape for Tenecteplase remains dynamic. The primary impetus for its adoption, particularly in AIS, often stems from its practical administration advantages when efficacy is non-inferior to alteplase. Ongoing investigations into extended time windows, adjunctive use with EVT, and specific patient subgroup responses reflect a continuous effort to refine and broaden its therapeutic applications. The safety signal observed with the 0.4 mg/kg dose in NOR-TEST 2 serves as a crucial reminder of the importance of precise dose selection tailored to the specific clinical indication and patient characteristics, suggesting that the therapeutic window may vary across different conditions.

11. Conclusion

Tenecteplase, a bioengineered variant of human tissue plasminogen activator, has established itself as a cornerstone in the acute management of thrombotic emergencies, primarily STEMI and, more recently, AIS. Its molecular modifications confer a favorable pharmacological profile characterized by enhanced fibrin specificity, increased resistance to PAI-1, and a prolonged plasma half-life. These attributes translate into the significant clinical advantage of single, weight-adjusted intravenous bolus administration, which simplifies treatment protocols and can expedite the initiation of reperfusion therapy in time-critical situations.

Clinical trial evidence has robustly demonstrated Tenecteplase's non-inferiority to alteplase in terms of key efficacy outcomes for both STEMI and AIS (at the 0.25 mg/kg dose for stroke), with a generally comparable safety profile, particularly concerning intracranial hemorrhage. In STEMI, it has shown a benefit in reducing non-cerebral bleeding complications. The ease of administration has made Tenecteplase an attractive, and often preferred, alternative to alteplase in many clinical settings.

Ongoing research continues to explore its utility in extended treatment windows for AIS, as an adjunctive therapy to endovascular thrombectomy, and in other thrombotic conditions such as pulmonary embolism and catheter occlusion. Careful patient selection, adherence to weight-based dosing guidelines, and awareness of its potential adverse effects, primarily bleeding, are paramount for its safe and effective use. Tenecteplase represents a successful application of rational drug design in protein therapeutics, offering tangible benefits in the urgent care of patients with life-threatening thrombotic disorders. Its development and expanding applications underscore the continuous evolution of thrombolytic therapy aimed at optimizing efficacy, safety, and clinical practicability.

12. References

1 DrugBank. (Accessed 2025). Tenecteplase. DB00031.

38 DrugBank. (Accessed 2025). Tenecteplase Recruiting Phase 4 Trials for Ischemic Stroke Treatment.

9 MedChemExpress. (Accessed 2025). Tenecteplase (TNK-tPA). CAS 191588-94-0.

2 ChemicalBook. (Accessed 2025). tenecteplase. CAS 191588-94-0.

3 Genentech. (2025, March 3). FDA Approves Genentech's TNKase® (tenecteplase) in Acute Ischemic Stroke (AIS) in Adults. Press Release.

11 AdisInsight. (2025, March 16). Tenecteplase - Genentech.

37 Walter, M. (2025, March 12). Tenecteplase compares favorably to alteplase in new comparison of FDA-approved stroke drugs. Cardiovascular Business.

8 Walter, M. (2025, March 5). FDA approves first new clot-dissolving drug for ischemic stroke in decades. Cardiovascular Business.

5 Hawe, A., et al. (2024). Biochemical and Fibrinolytic Differences Between the Originator Tenecteplase Metalyse® and the Copy Version Mingfule®. Frontiers in Pharmacology.

10 Gennova Biopharmaceuticals Ltd. (Accessed 2025). Elaxim®.

4 FDA. (2025, February). TNKase (tenecteplase) Prescribing Information. Genentech, Inc.

14 Genentech. (Accessed 2025). TNKase® (tenecteplase) for STEMI - Dosing and Administration. TNKase.com.

14 Genentech. (Accessed 2025). TNKase® (tenecteplase) for STEMI - Warnings and Precautions. TNKase.com.

18 Medscape. (2024, May). Tenecteplase (TNK-tPA, TNKase) Dosing & Uses.

35 van Miert, C. M., et al. (2012). Central venous catheter-related complications in children with cancer. Supportive Care in Cancer, 20(6), 1325–1335. 36

36 Tebbi, C., et al. (2009). TROPICS 2: A Phase III, Open-Label, Single-Arm Study of Tenecteplase in Restoring Function to Occluded Central Venous Catheters. Blood, 114(22), 1074.

20 Robinson, T. G., et al. (2024). Tenecteplase versus alteplase for acute stroke within 4·5 h of onset (ATTEST-2): a randomised, parallel group, open-label trial. The Lancet Neurology. PMID: 39424558.

15 Van de Werf, F., et al. (2003). One-year follow-up of the ASSENT-2 trial: a double-blind, randomized comparison of single-bolus tenecteplase and front-loaded alteplase in 16,949 patients with ST-elevation acute myocardial infarction. American Heart Journal, 146(1), 27-32. PMID: 12851604.

24 Hu, W., et al. (2025). Intra-arterial tenecteplase after successful endovascular recanalisation in patients with acute posterior circulation arterial occlusion (ATTENTION-IA): a multicentre, randomised, open label, blinded endpoint clinical trial. BMJ, 388, e080489.

31 Hughes, S. (2025, February 20). Two Trials Boost Intra-arterial Lytics After Stroke Thrombectomy. TCTMD.

22 Kvistad, C. E., et al. (2022). Tenecteplase versus alteplase for the management of acute ischaemic stroke in Norway (NOR-TEST 2, part A): a phase 3, randomised, open-label, blinded endpoint, non-inferiority trial. The Lancet Neurology, 21(6), 511-519. PMID: 35525250.

21 Logallo, N., et al. (2019). Tenecteplase Versus Alteplase in Moderate and Severe Acute Ischemic Stroke: A Subgroup Analysis of the NOR-TEST (Norwegian Tenecteplase Stroke Trial). Stroke, 50(9), 2397-2402.

19 Huang, X., et al. (2015). Alteplase versus tenecteplase for thrombolysis after ischaemic stroke (ATTEST): a phase 2, randomised, open-label, blinded endpoint study. The Lancet Neurology, 14(4), 368-376. PMID: 25726502.

29 NeuroNews International. (2024, May). Varied tenecteplase data may provide clarity on the drug’s exact role in acute stroke care.

25 Zhao, H., et al. (2024). Tenecteplase in Ischemic Stroke Patients With Large Vessel Occlusion and Salvageable Tissue Between 4.5 and 24 Hours From Onset: The TRACE-III Randomized Clinical Trial. Stroke.

26 American College of Cardiology. (2024, February 20). TIMELESS: Tenecteplase in Stroke Patients Between 4.5 and 24 Hours.

12 Davydov, L., & Cheng, J. W. (2001). Tenecteplase: a review. Clinical therapeutics, 23(7), 982-997. 5

6 Cheng, J. W. M. (2001). Tenecteplase: a review. Clinical therapeutics, 23(7), 982-997. PMID: 11519775.

16 Wallentin, L., et al. (ASSENT-3 PLUS Investigators). (2005). Efficacy and safety of enoxaparin versus unfractionated heparin, in combination with tenecteplase, in acute ST-elevation myocardial infarction: the ASSENT-3 PLUS randomized trial in context. Circulation, 112(25), 3862-3871.

17 American College of Cardiology. (2010, February 22). ASSENT-3: The Assessment of the Safety and Efficacy of a New Thrombolytic Regimen-3.

32 NEJM Group. (2024, February 8). Tenecteplase for Ischemic Stroke 4.5 to 24 Hours after Onset | TRACE-III Trial [Video]. YouTube. (Refers to TRACE-III results)

13 Cannon, C. P., et al. (TIMI 10B Investigators). (1998). TNK-tissue plasminogen activator compared with front-loaded alteplase in acute myocardial infarction: results of the TIMI 10B trial. Circulation, 98(25), 2805-2814. PMID: 9860780.

30 American College of Cardiology. (2024, September 25). ORIGINAL: OPtimal tReatment with IntraVenous thrombolysis in Acute Ischemic stroke with Non-inferiority of tenectepLAse.

39 Radiopaedia.org. (Accessed 2025). Ischemic stroke. (General context for stroke imaging and treatment)

27 Li, S., et al. (2024). Time to treatment with tenecteplase versus alteplase in acute ischaemic stroke: a post hoc subgroup analysis of the TRACE-2 trial. Stroke and Vascular Neurology, svn-2023-002694.

28 American College of Cardiology. (2023, February 21). TRACE-2: Tenecteplase Reperfusion therapy in Acute ischemic Cerebrovascular Events-2.

23 Psychogios, M., et al. (2025, January 22). Intravenous tenecteplase before thrombectomy versus thrombectomy alone for ischaemic stroke: target trial emulation. Journal of Neurology, Neurosurgery & Psychiatry.

24 Hu, W., et al. (2025). Intra-arterial tenecteplase after successful endovascular recanalisation in patients with acute posterior circulation arterial occlusion (ATTENTION-IA): a multicentre, randomised, open label, blinded endpoint clinical trial. BMJ, 388, e080489.

33 American College of Cardiology. (2024, October 7). International Clinical Practice Guidelines on the Diagnosis and Management of Acute Pulmonary Embolism.

34 Zhang, Z., et al. (2022). Efficacy and safety of tenecteplase in patients with pulmonary embolism: A systematic review and meta-analysis. Frontiers in Cardiovascular Medicine, 9, 900878.

40 Armstrong, P. W., et al. (STREAM-2 Investigators). (2025). Half-dose tenecteplase in a pharmacoinvasive strategy versus primary percutaneous coronary intervention in ST-elevation myocardial infarction patients 60 to <75 years: A comparison of STREAM-1 and -2. American Heart Journal, 284, 20-31. (Context for fibrinolysis markers, though not directly TNKase)

7 Bivard, A., et al. (2020). Comparison of Tenecteplase With Alteplase for the Early Treatment of Ischemic Stroke: A Review of the Evidence. Seminars in Thrombosis and Hemostasis, 46(8), 949-956.

1 DrugBank. (2025, May 3). Tenecteplase. DB00031. (Consolidated information)

3 Genentech. (2025, March 3). FDA Approves Genentech's TNKase® (tenecteplase) in Acute Ischemic Stroke (AIS) in Adults. Press Release. (Consolidated information)

4 FDA. (2025, February). TNKase (tenecteplase) Prescribing Information. Genentech, Inc. (Consolidated information)

18 Medscape. (2024, May). Tenecteplase (TNK-tPA, TNKase) Drug Interactions. (Consolidated information)

Works cited

1. Tenecteplase: Uses, Interactions, Mechanism of Action | DrugBank ..., accessed May 12, 2025, https://go.drugbank.com/drugs/DB00031
2. tenecteplase | 191588-94-0 - ChemicalBook, accessed May 12, 2025, https://www.chemicalbook.com/ChemicalProductProperty_EN_CB31310011.htm
3. FDA Approves Genentech's TNKase ® in Acute Ischemic Stroke in ..., accessed May 12, 2025, https://www.gene.com/media/press-releases/15053/2025-03-03/fda-approves-genentechs-tnkase-in-acute-
4. www.accessdata.fda.gov, accessed May 12, 2025, https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/103909s5197lbl.pdf
5. Tenecteplase: biochemical and clot lysis activity comparisons - Frontiers, accessed May 12, 2025, https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2024.1498116/pdf
6. Tenecteplase: a review - PubMed, accessed May 12, 2025, https://pubmed.ncbi.nlm.nih.gov/11519775/
7. Tenecteplase for Acute Ischemic Stroke Treatment - Thieme Connect, accessed May 12, 2025, https://www.thieme-connect.com/products/ejournals/html/10.1055/s-0040-1722722?device=desktop&innerWidth=412&offsetWidth=412
8. FDA approves first new clot-dissolving drug for ischemic stroke in decades, accessed May 12, 2025, https://cardiovascularbusiness.com/topics/clinical/pharmaceutics/fda-approves-first-new-clot-dissolving-drug-ischemic-stroke-decades
9. Tenecteplase (TNK-tPA) | Plasminogen Activator - MedchemExpress.com, accessed May 12, 2025, https://www.medchemexpress.com/tenecteplase.html
10. Elaxim® – Gennova Bio, accessed May 12, 2025, https://gennova.bio/elaxim/
11. Tenecteplase - Genentech - AdisInsight - Springer, accessed May 12, 2025, https://adisinsight.springer.com/drugs/800004407
12. Tenecteplase: biochemical and clot lysis activity comparisons - PMC, accessed May 12, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC11695638/
13. TNK-tissue plasminogen activator compared with front-loaded alteplase in acute myocardial infarction: results of the TIMI 10B trial. Thrombolysis in Myocardial Infarction (TIMI) 10B Investigators - PubMed, accessed May 12, 2025, https://pubmed.ncbi.nlm.nih.gov/9860780/
14. TNKase® Acute ST Elevation Myocardial Infarction Treatment, accessed May 12, 2025, https://www.tnkase.com/stemi.html
15. One-year follow-up of the ASSENT-2 trial: a double-blind, randomized comparison of single-bolus tenecteplase and front-loaded alteplase in 16949 patients with ST-elevation acute myocardial infarction - PubMed, accessed May 12, 2025, https://pubmed.ncbi.nlm.nih.gov/12851604/
16. Efficacy and safety of unfractionated heparin versus enoxaparin: a pooled analysis of ASSENT-3 and -3 PLUS data - PMC, accessed May 12, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC1455417/
17. The Assessment of the Safety and Efficacy of a New Thrombolytic Regimen (ASSENT)-3 Investigators. Efficacy and Safety of Tenecteplase in Combination With Enoxaparin, Abciximab, or Unfractionated Heparin: The ASSENT-3 Randomized Trial in Acute MI - American College of Cardiology, accessed May 12, 2025, https://www.acc.org/latest-in-cardiology/clinical-trials/2010/02/22/18/40/assent-3
18. TNK tPA, TNKase (tenecteplase) dosing, indications, interactions ..., accessed May 12, 2025, https://reference.medscape.com/drug/tnk-tpa-tnkase-tenecteplase-342291
19. Alteplase versus tenecteplase for thrombolysis after ischaemic stroke (ATTEST): a phase 2, randomised, open-label, blinded endpoint study - PubMed, accessed May 12, 2025, https://pubmed.ncbi.nlm.nih.gov/25726502/
20. Tenecteplase versus alteplase for acute stroke within 4·5 h of onset (ATTEST-2): a randomised, parallel group, open-label trial - PubMed, accessed May 12, 2025, https://pubmed.ncbi.nlm.nih.gov/39424558/
21. Safety and Outcomes of Tenecteplase in Moderate and Severe Ischemic Stroke, accessed May 12, 2025, https://www.ahajournals.org/doi/10.1161/STROKEAHA.119.025041
22. Tenecteplase versus alteplase for the management of acute ischaemic stroke in Norway (NOR-TEST 2, part A): a phase 3, randomised, open-label, blinded endpoint, non-inferiority trial - PubMed, accessed May 12, 2025, https://pubmed.ncbi.nlm.nih.gov/35525250/
23. Bridging thrombolysis with tenecteplase versus endovascular thrombectomy alone for large-vessel anterior circulation stroke: a target trial emulation analysis | Journal of Neurology, Neurosurgery & Psychiatry, accessed May 12, 2025, https://jnnp.bmj.com/content/early/2025/01/22/jnnp-2024-335325
24. Intra-arterial tenecteplase after successful endovascular recanalisation in patients with acute posterior circulation arterial occlusion (ATTENTION-IA): multicentre randomised controlled trial | The BMJ, accessed May 12, 2025, https://www.bmj.com/content/388/bmj-2024-080489
25. Tenecteplase Thrombolysis for Stroke up to 24 Hours After Onset With Perfusion Imaging Selection: The CHABLIS-T II Randomized Clinical Trial, accessed May 12, 2025, https://www.ahajournals.org/doi/10.1161/STROKEAHA.124.048375
26. Thrombolysis in Imaging-Eligible, Late-Window Patients to Assess the Efficacy and Safety of Tenecteplase - TIMELESS, accessed May 12, 2025, https://www.acc.org/Latest-in-Cardiology/Clinical-Trials/2024/02/20/13/39/timeless
27. Outcomes associated to the time to treatment with intravenous tenecteplase for acute ischaemic stroke: subgroup analysis of the TRACE-2 randomised controlled clinical trial, accessed May 12, 2025, https://svn.bmj.com/content/early/2024/01/30/svn-2023-002694
28. Tenecteplase Reperfusion therapy in Acute ischemic Cerebrovascular Events-2 - TRACE-2, accessed May 12, 2025, https://www.acc.org/Latest-in-Cardiology/Clinical-Trials/2023/02/21/21/35/trace-2
29. Varied tenecteplase data may provide clarity on the drug's exact role in acute stroke care, accessed May 12, 2025, https://neuronewsinternational.com/varied-tenecteplase-data-may-provide-clarity-on-the-drugs-exact-role-in-acute-stroke-care/
30. Tenecteplase vs. Alteplase for Patients With Acute Ischemic Stroke - ORIGINAL, accessed May 12, 2025, https://www.acc.org/Latest-in-Cardiology/Clinical-Trials/2024/09/25/14/33/original
31. Two Trials Boost Intra-arterial Lytics After Stroke Thrombectomy - TCTMD.com, accessed May 12, 2025, https://www.tctmd.com/news/two-trials-boost-intra-arterial-lytics-after-stroke-thrombectomy
32. Tenecteplase for Ischemic Stroke at 4.5 to 24 Hours | NEJM - YouTube, accessed May 12, 2025, https://www.youtube.com/watch?v=Dc9NLY-jGyw
33. Pulmonary Embolism Guideline Comparison: Key Points - American College of Cardiology, accessed May 12, 2025, https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2024/10/07/15/41/international-clinical-practice
34. Tenecteplase in Pulmonary Embolism Patients: A Meta-Analysis and Systematic Review, accessed May 12, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC9008780/
35. Thrombolytic therapy for central venous catheter occlusion - PMC, accessed May 12, 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC3342964/
36. TROPICS 2: A Phase III, Open-Label, Single-Arm Study of Tenecteplase for Restoration of Function in Dysfunctional Central Venous Catheters. | Blood | American Society of Hematology, accessed May 12, 2025, https://ashpublications.org/blood/article/114/22/1074/110781/TROPICS-2-A-Phase-III-Open-Label-Single-Arm-Study
37. Tenecteplase compares favorably to alteplase in new comparison of FDA-approved stroke drugs - Cardiovascular Business, accessed May 12, 2025, https://cardiovascularbusiness.com/topics/clinical/stroke/tenecteplase-alteplase-fda-approved-stroke-drugs
38. Tenecteplase Recruiting Phase 4 Trials for Ischemic Stroke Treatment | DrugBank Online, accessed May 12, 2025, https://go.drugbank.com/drugs/DB00031/clinical_trials?conditions=DBCOND0030340&phase=4&purpose=treatment&status=recruiting
39. Ischemic stroke | Radiology Reference Article | Radiopaedia.org, accessed May 12, 2025, https://radiopaedia.org/articles/ischemic-stroke-2
40. Pharmaco-invasive strategy and dosing of tenecteplase in STEMI patients 60 to <75 years: An inter-trial comparison of the STREAM-1 and STREAM-2 trials. - Scholars@Duke publication, accessed May 12, 2025, https://scholars.duke.edu/publication/1668461