Bolstered by promising response data from its Phase II study, Amgen announced Thursday it got the FDA’s green light for its first-in-class bi-specific T-cell engager Imdelltra for extensive-stage small lung cancer.
The FDA on Thursday approved Amgen’s bispecific T-cell engager tarlatamab, which will now carry the brand name Imdelltra, for the treatment of extensive-stage small lung cancer in patients with disease progression on or after platinum chemotherapy.
Imdelltra is approved under the regulator’s accelerated pathway based on treatment response and duration of response data. To maintain the approval, Amgen will need to verify Imdelltra’s clinical benefits in a Phase III confirmatory trial. The FDA also gave Imdelltra a boxed warning for cytokine release syndrome and neurologic toxicity.
Jay Bradner, CSO and executive vice president of R&D at Amgen, called Thursday’s regulatory win a “pivotal moment” for patients with extensive-stage small lung cancer (ES-SCLC), with Imdelltra a “transformative option demonstrating long-lasting responses,” especially in patients exposed to prior treatments.
Designed as an intravenous infusion, Imdelltra is a first-in-class bispecific antibody that can bind to both the DLL3 protein on tumor cells and the CD3 antigen on T cells. This mechanism of action allows Imdelltra to activate the body’s immune players and induce the destruction of DLL3-expressing cancer cells.
DLL3 is expressed in 85% to 96% of SCLC cases but the protein is rarely found on healthy cells, according to Amgen. The company is also developing tarlatamab for neuroendocrine prostate cancer, for which the candidate is currently in Phase I.
Thursday’s accelerated approval was backed by data from the Phase II DeLLphi-301 trial, which administered Imdelltra at a 10-mg or 100-mg dose every two weeks. In October 2023, Amgen published data from the mid-stage study in The New England Journal of Medicine, touting an objective response rate of 40% and 32% in the 10-mg and 100-mg dose groups, respectively.
Of those with objective response to Imdelltra, 59% sustained the response for a median duration of at least six months. Median progression-free survival was 4.9 months in the 10-mg group, while overall survival was 14.3 months.
With these data in hand, Amgen filed its Biologics License Application with the FDA which accepted the submission in December 2023 and granted it priority review. The regulator’s verdict was initially due on June 12, 2024.
Imdelltra’s approval on Thursday puts Amgen ahead of its competitors including Boehringer Ingelheim, whose own SCLC bi-specific T-cell engager BI 764532 is currently being assessed in a Phase II trial. In November 2023, Novartis and Legend Biotech also joined the race with a potential $1-billion agreement to develop a DLL3-targeting CAR-T therapy.
Tristan Manalac is an independent science writer based in Metro Manila, Philippines. Reach out to him on LinkedIn or email him at tristan@tristanmanalac.com or tristan.manalac@biospace.com.
