FDA Sets Review Date for Bispecific Antibody for Solid Tumor

The FDA has accepted and granted priority review for Amgen’s biologics license application (BLA) for tarlatamab to treat adult patients with advanced small cell lung cancer (SCLC) after disease progression on platinum-based chemotherapy. The FDA has set a Prescription Drug User Fee Action (PDUFA) date for tarlatamab of June 12, 2024.

Tarlatamab is a first-in-class delta-like ligand 3 (DLL3) targeting Bispecific T-cell Engager (BiTE) therapy. If approved, it would be the first for approved bispecific antibody to treat a solid tumor. Tarlatamab targets CD3 on T cells and DLL3 on small cell lung cancer cells. About 85% to 96% of patients have expression of DLL3 on the cell surface of small cell lung cancer cells, with minimal expression in normal cells.

Small cell lung cancer is an aggressive solid tumor with a median survival of about 12 months following initial therapy and a 7% five-year relative survival rate.

Luis Paz-Ares, M.D., Ph.D.

“In the current third-line treatment of SCLC, patients face a dire prognosis, with response rates ranging between 14% and 21% and median overall survival less than six months,” Luis Paz-Ares, M.D., Ph.D., chairman, Medical Oncology Department, Hospital Doce de Octubre; Head, Lung Cancer Unit, National Oncology Research Center (CNIO); associate professor, Universidad Complutense, said in a press release.

The regulatory application is based on the phase 2 results from the DeLLphi-301 clinical trial, which studied 220 patients with advanced small cell lung cancer. The study assessed two different doses of tarlatamab. The data demonstrated antitumor activity with a durable response and encouraging survival outcomes in previously treated small cell lung cancer.

An objective response occurred in 40% of the patients in the 10-mg group and in 32% of those in the 100-mg group. Among patients with an objective response, the duration of response was at least six months in 59%. The median progression-free survival was 4.9 months in the 10-mg group and 3.9 months in the 100-mg group; the estimates of overall survival at 9 months were 68% and 66% of patients, respectively.

The most common adverse events were cytokine-release syndrome, decreased appetite, fever, and metallic taste in mouth. Three percent of patients discontinued tarlatamab because of treatment-related adverse events.

Results from the study were recently presented during the 2023 European Society for Medical Oncology (ESMO) Congress and published in the New England Journal of Medicine.

Amgen is conducting additional trials of tarlatamab in small cell lung cancer: a phase 1b study evaluating tarlatamab in combination with an anti-PD-1 therapy in second-line treatment; a phase 1b study investigating tarlatamab in combination with standard of care therapies in first-line treatment; and a phase 3 trial comparing tarlatamab monotherapy with standard of care chemotherapy in second-line treatment; and the recently-initiated phase 3 trial of tarlatamab following chemoradiotherapy in earlier settings.

Amgen is also investigating tarlatamab in a phase 1b study of tarlatamab in de novo or treatment-emergent neuroendocrine prostate cancer.