Eftilagimod Alfa Plus Keytruda Shows Positive Results in Head and Neck Cancer

Some patients with head and neck squamous cell carcinoma who received a combination of efti and Keytruda showed promising results.

The combination of efti (eftilagimod alfa) and Keytruda (pembrolizumab) was associated with positive results when used in the first-line setting for patients with recurrent or metastatic head and neck squamous cell carcinoma with negative PD-L1 expression, according to new study findings.

Updated efficacy and safety data from the TACTI-003 (KEYNOTE-PNC-34) phase 2b clinical trial was announced in a news release by biotechnology company Immutep Limited and presented at the European Society for Medical Oncology (ESMO) Virtual Plenary session.

The combination resulted in an objective response rate (patients whose disease responded partially or completely to treatment) of 35.5%, or 11 of 31 evaluable patients, with a complete response rate of 9.7%, or three out of 31 patients, and a disease control rate (patients whose disease shrunk, disappeared or stabilized) of 58%. According to the news release, one patient with early progressive disease also eventually showed a partial response and remained on therapy after 14 months, resulting in an objective response rate of 38.7%.

More than half of the patients in this cohort received treatment for at least six months, and three more patients were approaching that benchmark as of the data cut-off of March 11, 2024, according to the news release, which also noted that no new safety signals were observed with the combination.

"The high response rate from this novel immunotherapy combination is well above other treatment approaches without chemotherapy,” stated Dr. Robert Metcalf of the Christie NHS Foundation Trust in the United Kingdom, in the news release. “It matches historical response rates from chemotherapy-based treatments but without the associated toxicities. This is really significant for patients with head and neck squamous cell carcinomas who have a [combined positive score, which determines the expression of PD-L1] less than one and for whom chemotherapy is the current first line treatment. Achieving complete responses in this group bodes well for this immunotherapy combination's future potential, especially given the positive trend in response durability. The clinically meaningful response rate and high unmet medical need warrant further investigation of [efti] plus [Keytruda] in this patient population."

Metcalf presented the TACTI-003 findings at the ESMO Virtual Plenary session.

Efti was described in the news release as a “LAG-3 protein and MHC Class 2 agonist that stimulates both innate and adaptive immunity for the treatment of cancer.” Keytruda, an immune checkpoint inhibitor, is a type of immunotherapy that stops cancer cells from suppressing a patient’s immune system, as explained by the National Cancer Institute.

Efti, according to Immutep, has previously received Fast Track designation from the Food and Drug Administration (FDA) for the first-line treatment of patients with head and neck squamous cell carcinoma, regardless of PD-L1 expression. The Fast Track process, according to the FDA’s website, is “designed to facilitate the development and expedite the review of drugs to treat serious conditions and fill an unmet medical need. The purpose is to get important new drugs to the patient earlier.”

The TACTI-003 trial, with 171 participants, is estimated to be completed in March of 2025, according to its listing on clinicaltrials.gov.

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