Summit Therapeutics (NASDAQ: SMMT) has announced a strategic clinical trial collaboration with Pfizer (NYSE: PFE) to investigate combination therapies pairing ivonescimab with multiple antibody drug conjugates (ADCs) across various solid tumor indications. The trials, set to commence in mid-2025, represent a significant step forward in developing innovative cancer treatment approaches.
Novel Therapeutic Approach
Ivonescimab stands out as a first-in-class bispecific antibody that combines PD-1 checkpoint inhibition with VEGF anti-angiogenesis effects in a single molecule. The drug's distinctive tetravalent structure enables enhanced binding in the tumor microenvironment, potentially offering superior targeting compared to existing therapies.
"Rapidly developing novel mechanisms that go beyond what is currently available to patients and physicians is what we believe will make the most significant impact for those facing the greatest challenges from cancer today," stated Bob Duggan and Dr. Maky Zanganeh, Summit's Co-CEOs.
Collaboration Framework
Under the agreement terms, Summit will supply ivonescimab while Pfizer manages trial operations. The studies will evaluate combinations of ivonescimab with Pfizer's vedotin-based ADCs across distinct solid tumor settings, focusing on safety profiles and anti-tumor activity.
Dr. Megan O'Meara, Head of Oncology Early Stage Development at Pfizer, emphasized the potential impact: "Together, we are advancing the exploration of our ADCs in rational, differentiated combinations with a bispecific antibody designed to address the unique complexities of tumor biology."
Clinical Development Status
Ivonescimab's development program has already demonstrated significant progress:
- Over 2,300 patients treated in global clinical studies
- Multiple Phase III trials ongoing, including HARMONi and HARMONi-3
- Recent marketing authorization approval in China (May 2024)
- Fast Track designation granted by FDA for the HARMONi trial
Mechanism of Action
The drug's innovative design features cooperative binding to both PD-1 and VEGF targets, with increased affinity in the presence of both molecules. This characteristic, combined with a 6-7 day half-life, suggests potential advantages over current treatment options in terms of efficacy and safety profiles.
Ongoing Clinical Programs
Summit is currently conducting several pivotal trials:
- HARMONi: Testing ivonescimab plus chemotherapy in EGFR-mutated NSCLC
- HARMONi-3: Evaluating combination therapy versus pembrolizumab with chemotherapy in first-line metastatic NSCLC
- HARMONi-7: Comparing ivonescimab monotherapy to pembrolizumab in high PD-L1 expression NSCLC
The collaboration with Pfizer marks a significant expansion of ivonescimab's development program, potentially accelerating the advancement of novel treatment options for cancer patients with serious unmet needs.
