Immutep Highlights LAG-3 Immunotherapy Results in Head and Neck Cancer

Immutep shares surged by 20% on Friday, partly recovering from losses incurred last month following the release of top-line results from its Phase IIb study. This study evaluated the LAG-3 immunotherapy eftilagimod alfa in conjunction with Merck & Co.’s Keytruda (pembrolizumab) for treating head-and-neck cancer. The initial data from the TACTI-003 trial, revealed last month, demonstrated an objective response rate (ORR) of 32.8% for the combination of eftilagimod alfa and Keytruda in patients with recurrent or metastatic head-and-neck squamous cell carcinoma with PD-L1 expression. This compared favorably to the 26.7% ORR for patients treated with Merck’s anti-PD-1 therapy alone. Specifically, in patients with high PD-L1 expression, the ORR for the combination therapy was 31%, compared to 18.5% for Keytruda alone. However, in patients with low PD-L1 expression, the response rates were similar for both treatment arms.

The newly released data come from a particular cohort in the trial that included 31 patients with negative PD-L1 expression. Preliminary results reported in April indicated an ORR of 26.9% for the combination therapy in this patient group. Immutep has now updated this figure to 35.5%, which includes three complete responses and a disease control rate of 58.1%.

Immutep has made strong assertions regarding these findings. The company claims that the observed ORR is “among the highest recorded for a treatment approach not containing chemotherapy” in this patient population. They also pointed out that this compares favorably to an ORR of just 5.4% for Keytruda alone in a subgroup analysis of the KEYNOTE-048 study. Robert Metcalf, who recently presented this data at a European Society for Medical Oncology (ESMO) virtual plenary session, interpreted the results as consistent with “historical response rates from chemotherapy-based treatments, but without the associated toxicities.” He emphasized that achieving complete responses in this patient group bodes well for the future potential of this immunotherapy combination, particularly given the positive trend in the durability of response.

Moreover, Immutep highlighted the favorable safety profile of the combination of eftilagimod alfa and Keytruda, noting that the findings from the TACTI-003 study will be discussed with regulatory agencies to determine the next steps.

Additionally, Immutep is also investigating this combination therapy in collaboration with Merck in the Phase III TACTI-004 trial. This trial is examining the dual regimen as a first-line treatment for patients with non-small-cell lung cancer, regardless of their PD-L1 expression status.