Immutep shares jumped nearly 20% on Friday after data showed its LAG-3 therapy—plus Keytruda—elicited strong response rates in head and neck squamous cell carcinoma patients in the front-line setting.
Immutep on Friday posted data from its ongoing Phase IIb TACTI-003 trial, demonstrating that its investigational LAG-3 therapy eftilagimod alfa elicited high response rates when used with Merck’s Keytruda for the first-line treatment of patients with metastatic head and neck squamous cell carcinoma.
The results, which were presented at the European Society of Molecular Oncology (ESMO) Virtual Plenary session on Thursday, demonstrated a 35.5% objective response rate in patients treated with the eftilagimod alfa (efti)-based regimen. The disease control rate was 58.1%.
According to Immutep, the findings are “among the highest recorded for a chemotherapy-free approach” in head and neck cancer patients negative for PD-L1—the target patient population of TACTI-003.
Results also showed that efti plus Keytruda led to the complete disappearance of all signs of cancer in three of the 31 evaluable patients, resulting in a complete response rate of 9.7%. Immutep in its statement said that this “compares favorably” versus a historical control, in which none of the patients treated with an anti-PD-1 agent achieved complete response.
The Australian biotech’s stock surged 19% in premarket trading in response to the findings, according to SeekingAlpha.
Robert Metcalf, of the Christie NHS Foundation Trust in the U.K., said in a statement that efti’s response rate—when used as a first-line treatment option with Keytruda—is “well above other treatment approaches without chemotherapy” and “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,” Metcalf said, adding that demonstrating complete responses in particular “bodes well for this immunotherapy combination’s future potential.” Metcalf presented the TACTI-003 data at the ESMO meeting.
With these “encouraging” data, Immutep is now preparing to engage regulatory authorities to determine the best path forward for efti. The investigational therapy has previously received the FDA’s Fast Track designation for the treatment of head and neck squamous cell carcinoma in the frontline setting, regardless of PD-L1 expression.
Efti is a soluble LAG-3 protein and a first-in-class activator of antigen-presenting cells. The drug candidate works by binding to MHC Class II proteins, activating the body’s innate and adaptive immune responses. Efti triggers the proliferation and activation of CD8+ cytotoxic T cells, dendritic cells, CD4+ helper T cells, natural killer cells and monocytes, while also promoting the expression of other key immune players such as interferon-gamma and CXCL10.
Beyond head and neck cancer, Immutep is also developing efti for non-small cell lung cancer and metastatic breast cancer.
