Loncastuximab tesirine, in conjunction with standard therapy, has shown promise in treating malignancy-associated hemophagocytic lymphohistiocytosis (Mal-HLH) driven by diffuse large B-cell lymphoma (DLBCL), according to a case study published in Cureus. The study highlights the potential of loncastuximab tesirine in managing this severe hyperinflammatory syndrome, which is associated with multiorgan dysfunction and high mortality.
Understanding HLH and its Challenges
Hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening condition characterized by excessive immune activation. Secondary HLH, often seen in adults, can be triggered by infections, malignancies, or autoimmune disorders. Malignancy-associated HLH (Mal-HLH) occurs in a small percentage (1% to 2.8%) of lymphoma patients. Diagnosing and treating HLH is challenging due to the different mechanisms driving primary and secondary forms. While corticosteroids are a standard early treatment for pediatric patients, data on Mal-HLH is limited, and omitting lymphoma-directed therapy has been linked to 100% mortality.
Loncastuximab Tesirine: A Targeted Approach
Loncastuximab tesirine is an antibody-drug conjugate targeting CD19, a protein expressed on B-cells. It has previously demonstrated efficacy in treating DLBCL. The drug works by attaching to CD19, minimizing systemic toxicity, and damaging the DNA of lymphoma cells. In the LOTIS-2 trial, approximately 50% of patients with relapsed or refractory DLBCL who had undergone two or more prior treatments showed a complete or partial response to loncastuximab tesirine.
Case Study Details and Outcomes
This study reports the experiences of three critically ill patients hospitalized with Mal-HLH from DLBCL treated with loncastuximab tesirine. The key outcomes assessed were ferritin response (defined as a greater than 50% reduction) and disease response to loncastuximab tesirine.
- Patient 1: Experienced recurrent Mal-HLH disease progression and received steroids followed by loncastuximab tesirine. Rapid improvement was observed, with a complete response noted 29 days after loncastuximab tesirine administration. However, the patient died due to a separate infection.
- Patient 2: Diagnosed with Mal-HLH and progression of DLBCL. Following stem cell therapy, loncastuximab tesirine was administered along with other HLH-directed therapies. The patient showed a 78% reduction from peak ferritin levels 11 days after loncastuximab tesirine treatment, with the onset of decline occurring one day after the first administration.
- Patient 3: Presented with infection and new-onset Mal-HLH. Despite HLH-directed therapy and loncastuximab tesirine, no clinical or laboratory response was observed, and the patient was transferred to inpatient hospice care.
Potential Advantages and Future Directions
Investigators selected loncastuximab tesirine for treatment due to its theorized advantages, including a potentially more rapid onset of action compared to other agents, as demonstrated by the rapid ferritin response in patients 1 and 2. They also considered it an appropriate bridge to CAR-T therapy or allogeneic transplant.
Expert Opinion
"While none of the three patients were successfully bridged to potentially curative therapy, we believe loncastuximab tesirine has favorable activity and should be the latest addition in the armamentarium in DLBCL-driven Mal-HLH," the investigators concluded.
