Amgen is pulling the curtain on full data after releasing small snippets about its keenly watched KRAS inhibitor. The drug, tagged Sotorasib or AMG 510, checkmated tumor growth in 88% of patients with non-small cell lung cancer (NSCLC), cutting down tumors in one-third of patients.
The phase 1 data was taken from 59 patients with NSCLC, who received one to four dose levels of the drug. The maximum dose of 960 mg produced better results, suppressing tumor growth in 91% of patients, and shrinking tumors in 35% of patients compared to the 32% figure for all dose levels. The drug also kept cancer in check for a median of six months, though some patients went more than a year before noticing their disease deteriorate.
The results, presented at the European Society for Medical Oncology (ESMO) virtual meeting on Sunday, are encouraging for a patient group with minimal options. The study involved 129 patients with KRAS-mutated cancers, including colorectal cancer, NSCLC, and other solid tumors. Three-quarters of the patients had attempted two or more treatments, with all of the patients having undergone platinum chemotherapy and the majority of them (90%) having attempted a PD-1/PD-L1 drug.
"If you look at drugs like docetaxel that are typically used in this setting, the progression-free survival is usually two or three months, and the response rate is in the order of 10% to 20%," said Greg Friberg, Amgen's vice president of global development, oncology. "We see at least double from what we would anticipate seeing from those available therapies."
Sotorasib did not fare so well in colorectal cancer, suppressing tumors in just 7% of 42 patients, and curbing tumor growth in 73% of them. Of the 28 patients with "other tumor types," 14% noticed their tumors shrink, while 61% noticed their tumors stop growing.
The drug's safety profile looks decent, too-just over half of the patients suffered treatment-related side effects, such as fatigue, nausea, and diarrhea, with just 12% reporting adverse effects. One patient quit the study due to side effects. No drug-related deaths were recorded, nor were there dose-limiting toxicities, namely side effects severe enough to stop a patient from increasing to a higher dose.