- Amgen is expanding testing of its closely watched cancer drug Lumakras to include more people with pancreatic and other tumors after disclosing early study results that showed the therapy might help some patients with the tough-to-treat cancer type.
- Among 38 patients with advanced and heavily pretreated pancreatic cancer, eight, or 21%, had a partial tumor response to Lumakras, according to data from an early-stage trial that Amgen disclosed Monday. Median progression-free survival, a measure of how long patients go without disease progression or dying, was four months, Amgen said.
- Both the tumor response rate and progression-free survival figure suggest at best modest efficacy for Lumakras, and likely will change as Amgen studies the drug in larger groups of pancreatic cancer patients. The disease is particularly difficult to treat: Five-year survival rates are 10% and less than one-fifth of patients respond to the second drug they're given.
Lumakras is the first marketed drug that's capable of targeting KRAS mutations, which are commonly found in certain lung, colon and pancreatic cancers. Currently, Lumakras is only approved to treat locally advanced or metastatic non-small cell lung cancers, for which Amgen's clinical trial evidence is most supportive of the drug's benefit.
Data in colorectal cancer have been less compelling and the biotech company now is exploring combinations of Lumakras with other drugs, like the older targeted therapy Vectibix.
The trial results disclosed by Amgen via press release on Monday afternoon give some hint of the drug's potential in pancreatic cancer, enough that the company now plans to enroll more patients in its Phase 1/2 study dubbed CodeBreak 100.
The trial is designed to expand as Amgen explores use of Lumakras in combination with other drugs and in different tumor types.
According to the early data, treatment with Lumakras held tumors in check — meaning they didn't grow past a certain size — in 32 of the 38 patients, while shrinking tumors in eight. Of those eight, two were still responding to treatment through the data cut-off of Nov. 1, 2021. Overall, patients in the group, four-fifths of whom were on at least their third cancer medicine, survived a median of almost seven months following Lumakras.
While very short, that overall survival time is one month longer than what Amgen said was typical following two treatments.
According to Amgen, about 40% of patients in the cohort had drug-related reactions, none of which led to death or for study participants to stop treatment. More severe cases of diarrhea and fatigue were reported in two patients, respectively.
Results will also be presented Tuesday afternoon as part of the American Society of Clinical Oncology's monthly plenary session.
Along with Amgen, biotech Mirati Therapeutics is developing its KRAS-targeting drug adagrasib in lung, colon and pancreatic cancers. Data disclosed by Mirati in January suggested a higher response rate and longer progression-free survival in previously treated pancreatic cancer, but the data were from only 10 patients. (Mirati recently asked the FDA for approval of adagrasib in non-small cell lung cancer.)
Both companies' drugs target a specific type of KRAS mutation known as G12C. While common in non-small cell lung cancer, it's less prevalent in colon and pancreatic tumors.
Since Lumakras' approval last year, the drug has been prescribed to approximately 2,000 lung cancer patients, according to Amgen. Sales for 2021 totaled $90 million, below the estimates of analysts, who expect Lumakras to become a top-seller.