The experimental KRAS inhibitor sotorasib led to rapid, deep and durable responses in more than a third of people with non-small-cell lung cancer (NSCLC), according to research presented at the virtual World Conference on Lung Cancer.

The KRAS gene makes proteins that regulate cell growth. Once considered “undruggable,” KRAS is the most commonly altered gene in people with cancer. Sotorasib targets a specific mutation, known as KRAS G12C, found in about 13% of people with NSCLC.

In an analysis of 126 heavily treated NSCLC patients in the Phase II CodeBreaK 100 trial, the overall response rate was 37% after a year of follow-up, including three people with complete remission. Another 44% had stable disease, yielding a disease control rate of 81%. The median progression-free survival time was 6.8 months.

The Phase III CodeBreaK 200 trial is now testing sotorasib versus docetaxel chemotherapy. Amgen has submitted study data to the Food and Drug Administration, and sotorasib could become the first approved KRAS inhibitor later this year.