Immutep's Eftilagimod Alpha Shows Promise in Head and Neck Cancer Treatment

Immutep, an Australian biotech company, has reported encouraging results from a phase 2b trial of its LAG-3 candidate eftilagimod alpha in combination with Merck & Co.'s Keytruda for the treatment of head and neck squamous cell carcinoma (HNSCC). The data suggests a potential path to approval for this immunotherapy combination, particularly in patients with PD-L1-negative tumors.

Impressive Survival Data in PD-L1-Negative HNSCC Patients

The latest results from the Keynote-C34 (Tacti-003) trial show that the combination of eftilagimod alpha and Keytruda achieved a median overall survival of 17.6 months in first-line treatment of recurrent or metastatic HNSCC patients with PD-L1 expression below a combined positive score (CPS) of 1. This outcome, derived from 31 evaluable patients in cohort B of the trial, appears to surpass historical data from existing standard-of-care regimens.

Jefferies analyst David Stanton, M.D., described the survival readout as "impressive," highlighting the potential significance of these results in the context of current treatment options. The lack of an active internal control arm in the trial necessitates caution in direct comparisons, but the data nonetheless presents a compelling case for further investigation.

Potential for a Chemo-Free Immunotherapy Regimen

Immutep CEO Marc Voigt emphasized the value proposition of the eftilagimod-Keytruda combination as a potential immunotherapy-only regimen for PD-L1-negative patients. Current standards of care for this patient population typically include chemotherapy, which can be associated with significant side effects.

Eftilagimod alpha, a LAG-3 fusion protein, works by activating antigen-presenting cells to enhance immune responses. This mechanism of action complements Keytruda's PD-1 inhibition, potentially offering a more targeted and tolerable approach to cancer treatment.

Regulatory Path and Market Positioning

Given the strength of the efficacy and safety results, Immutep has requested a meeting with the FDA to discuss potential paths to approval. The company believes that the high unmet need in first-line treatment of PD-L1-negative HNSCC could facilitate a regulatory pathway for eftilagimod alpha, which already holds an FDA "fast track" designation in this indication.

Immutep appears to be targeting a niche market, as PD-L1-negative disease represents approximately 20% of first-line HNSCC patients. The company notes a lack of competitor chemo-free trials specifically targeting this population, potentially positioning eftilagimod alpha as a unique treatment option if approved.

The latest data builds on previously reported tumor response rates, with the eftilagimod-Keytruda combination achieving a 35.5% objective response rate, including 12.9% complete responses, in cohort B of the Tacti-003 trial. These figures compare favorably to historical data from Keytruda-chemotherapy combinations in similar patient populations.

As the pharmaceutical industry continues to explore novel immunotherapy combinations, Immutep's eftilagimod alpha represents a promising candidate in the evolving landscape of head and neck cancer treatment. The company's focus on PD-L1-negative patients could potentially address an important gap in current therapeutic options, offering hope for improved outcomes in this challenging disease setting.