Amgen's Imdylltra gains conditional MHRA approval for lung cancer

Amgen recently announced that Imdylltra (tarlatamab), a new treatment for extensive-stage small cell lung cancer (ES-SCLC), has received conditional approval from the UK's Medicines and Healthcare products Regulatory Agency (MHRA). This approval is considered a significant advancement for patients suffering from lung cancer, particularly those who have not responded to at least two prior treatments, including platinum-based chemotherapy. The MHRA's decision was made on December 31, and Amgen shared the news in a press release on January 6.

Tony Patrikios, the UK and Ireland executive medical director at Amgen, emphasized the urgent need for innovative treatments for ES-SCLC, noting the particularly poor outcomes associated with this advanced stage of lung cancer. Despite the authorization, Amgen's stock prices have remained steady, although they have fallen from the highs of 2024. This decline is largely attributed to the underwhelming performance of its weight loss medication, MariTide.

Imdylltra's conditional marketing authorization was granted based on data from the Phase II DeLLphi-301 trial (NCT05060016). This type of approval is typically awarded when the complete clinical data is not yet available but is expected soon. In the trial, Imdylltra demonstrated an objective response rate of 41% and a median duration of response of 9.7 months when administered intravenously every two weeks at a dose of 10mg.

Small cell lung cancer (SCLC) is an aggressive subtype of lung cancer, accounting for approximately 15% of lung cancer cases, and is less common than non-small-cell lung cancer (NSCLC). Patients with extensive-stage SCLC typically have a median survival time of 9 to 12 months. Although first-line platinum-based chemotherapy is initially effective, relapses are common within a few months. Amgen reports that the median overall survival with existing second-line treatments is roughly 26 weeks, and there is a lack of options for third-line treatment.

Imdylltra is a bispecific T-cell engager (BiTE) that targets the protein delta-like ligand 3 (DLL3) found in tumor cells. It also binds to T-cells, activating immune pathways that result in the destruction of tumor cells. The U.S. Food and Drug Administration (FDA) approved tarlatamab under the brand name Imdelltra in May 2024, making it the first and only T-cell engager therapy available for ES-SCLC.

Amgen's Imdylltra is projected to generate $217 million globally this year, with expectations of reaching blockbuster status by 2029, according to GlobalData’s Pharma Intelligence Centre. The treatment has shown promising efficacy, but it is also associated with side effects. The FDA's label for Imdylltra includes a boxed warning about cytokine release syndrome (CRS) and neurologic toxicity. Additional warnings and precautions relate to cytopenias, infections, hepatotoxicity, hypersensitivity, and embryo-fetal toxicity.

Previously, MSD's Keytruda (pembrolizumab) was an option for U.S. patients with metastatic SCLC who had experienced disease progression after platinum-based chemotherapy and at least one other prior treatment. However, MSD withdrew this indication in 2021 due to insufficient efficacy data.