Seven months after Amgen’s chief medical officer referred to trial results for the company's investigational lung cancer immunotherapy as a “watershed moment,” the FDA has signed off on Imdelltra (tarlatamab) to treat patients with extensive-stage small-cell lung cancer (ES-SCLC).
The breakthrough therapy is endorsed for patients whose disease has worsened after or throughout treatment with platinum-based chemotherapy. The accelerated approval—which was delivered nearly a month before the agency's June 12 target decision date—is contingent upon verification of clinical benefit in a confirmatory trial.
Imdelltra activates a patient’s T cells to attack Delta-like ligand 3 (DLL3)-expressing tumors. While SCLC cases comprise just 15% of lung cancers, they're typically deadlier and more aggressive than non-small cell lung cancer.
The bispecific T-cell engager (BiTE) molecule made waves in October at the European Society of Medical Oncology (ESMO) Congress. At the event, Amgen showed that a 10 mg infusion, given every two weeks, reduced tumors in 40% of SCLC patients who had failed on two previous lines of treatment.
The results from the phase 2 trial, which were published in the New England Journal of Medicine, prompted the “watershed” comment from Amgen’s CMO Paul Burton, M.D. to Fierce Biotech.
“This represents about a tripling of the duration of survival,” Burton said.
With data still yet to mature, the median length of overall survival stood at 14.3 months in a disease where median survival is expected to be about 5 months. The median duration of response was 9.7 months.
On Thursday in a release, Amgen’s R&D chief Jay Bradner called it a “pivotal moment for patients battling ES-SCLC.” The company will say more on Monday afternoon when it hosts a webcast with investors.
Imdelltra comes with a black-box warning for cytokine release syndrome (CRS) and neurologic toxicity, including immune effector cell-associated neurotoxicity syndrome (ICANS).
In the DeLLphi-301 trial, which included 187 patients on the 10 mg dose, there was one death from respiratory failure which was attributed to tarlatamab. In the trial, 55% of patients experienced CRS, most of them after the first or second dose, the company said.
“Given the limited options for patients with ES-SCLC, these results represent a meaningful improvement over current options, and there is no approved standard of care in third-line SCLC, for which Amgen estimates a U.S. prevalence of 2,000 to 3,500 patients,” Matt Phipps, an analyst at William Blair, wrote to clients.
William Blair says Imdelltra has blockbuster potential and projects 2028 sales at $842 million.
Amgen has priced Imdelltra at $31,500 for the first cycle and $30,000 for subsequent cycles. With a cycle of treatment lasting 28 days and the median duration of treatment extending for 5.5 cycles, the average cost per patient would come to $166,500, Amgen said.
Imdelltra becomes Amgen’s second BiTE on the market. Over the last decade, the FDA has approved Blincyto for five types of acute lymphoblastic leukemia (ALL). Last year, sales for the treatment were up 48% to $861 million.
EDITOR'S NOTE: This story was corrected to indicate the average cost per patient for a regimen of Imdelltra.