ASCO19: Amgen's KRAS inhibitor AMG 510 shrinks tumours in half of patients with lung cancer in early-stage study

Amgen announced Monday initial data from a Phase I study of AMG 510 as a monotherapy in patients with locally advanced or metastatic KRASG12C mutant solid tumours, with the experimental KRASG12C inhibitor demonstrating a response rate of 50 percent in subjects with non-small-cell lung cancer (NSCLC). Ahead of the American Society of Clinical Oncology (ASCO) annual meeting, the company disclosed that the response rate in these patients was 30 percent.  

"KRAS…remained undruggable due to a lack of traditional small-molecule binding pockets on the protein," remarked David Reese, executive vice president of R&D at Amgen, adding "AMG 510 seeks to crack the KRAS code by exploiting a previously hidden groove on the protein surface."  

In the Phase I study, 35 patients with heavily pre-treated metastatic KRASG12C mutant cancer, including NSCLC and colorectal cancer, were assigned to treatment with AMG 510 at one of four dose levels. At the ASCO meeting, results showed that in 10 patients with NSCLC, five experienced a partial response (PR), and another four had stable disease (SD), for a disease control rate of 90 percent. Meanwhile, the duration of response in the patients with PR ranged from 7.3 weeks to 27.4 weeks.  

Amgen noted that one patient with PR improved further to a complete response of the target lesions at week 18, after data cut-off. Meanwhile, 13 of 18 patients with colorectal cancer exhibited SD following treatment with AMG 510.

"In principle, this drug has the potential to be effective in any patient with the KRAS mutation," remarked Elliott Levy, Amgen's head of global development. "We have a plan to advance the drug rapidly through what would potentially be registrational studies," Levy noted, as Amgen competes with other companies, including Mirati Therapeutics, also developing drugs targeting KRAS mutations.

Commenting on the findings, SVB Leerink analyst Geoffrey Porges indicated that AMG 510 had a 35 percent likelihood of success in lung cancer. The analyst further estimated that the drug could amass $2.3 billion in revenue by 2028. For related analysis, see ViewPoints: Amgen presents ASCO tour de force.

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