Benzinga | Sep 19, 2021 09:55AM EDT

Mirati Therapeutics Announced Clinical Data with Investigational Adagrasib Showed Adagrasib Alone and With Cetuximab Demonstrated Significant Clinical Activity and Broad Disease Control in Patients with KRAS G12C-Mutated Colorectal Cancer; Data to be Presented at ESMO

Mirati Therapeutics, Inc. (NASDAQ:MRTX) today announced results from a cohort of the Phase 1/2 KRYSTAL1 study evaluating adagrasib at the 600mg BID dose as both monotherapy and in combination with cetuximab in patients with heavily pretreated colorectal cancer harboring a KRASG12C mutation. Results showed that adagrasib alone and with cetuximab demonstrated significant clinical activity and broad disease control in these patients. The findings (Abstract # LBA6) will be presented today at 9:47 a.m. ET as a late-breaking oral presentation during the Presidential Symposium II session at the European Society for Medical Oncology Congress (ESMO) 2021.

Logo (PRNewsfoto/Mirati Therapeutics, Inc.)

"Patients living with KRAS-mutated colorectal cancer face a significant medical need for new treatment options," said Dr. Jared Weiss M.D., lead study investigator and associate professor of medicine, division of oncology at University of North Carolina-Chapel Hill. "The positive results presented today show that adagrasib alone or in combination with cetuximab may improve clinical outcomes in patients with colorectal cancer harboring a KRASG12C mutation."

Summary of Clinical Results

As of May 25, 2021, 80% of patients enrolled in the adagrasib monotherapy arm (n=46) received at least two prior lines of systemic anticancer therapies, and had a median follow up of 8.9 months. Of the evaluable patients (n=45), results showed an investigator assessed response rate (RR) of 22%, including one unconfirmed partial response (PR), and a disease control rate (DCR) of 87%; the median duration of response (DOR) was 4.2 months. In all enrolled patients, the median progression free survival (PFS) was 5.6 months (95% Confidence Interval, CI: 4.1,8.3).

As of July 9, 2021, 90% patients enrolled in the adagrasib plus cetuximab arm (n=32) received at least two prior lines of systemic anticancer therapies, and had a median follow up of 7 months. Of the evaluable patients (n=28), results showed an investigator assessed RR of 43%, including two unconfirmed PRs and a DCR rate of 100%. After the data cutoff date, of the two unconfirmed PRs, follow up scans showed one patient had a confirmed PR, and the second patient progressed. At the time of the analysis, 63% (20/32) of enrolled patients remained on treatment.

Adagrasib monotherapy and in combination with cetuximab was well-tolerated in this study, with a manageable safety profile. Grade 3/4 treatment related adverse events (TRAEs) were observed in 30% of patients treated with adagrasib alone, and in 16% of patients treated with the combination. Treatment related adverse events led to treatment discontinuation in 6% of patients who received combination therapy and in none (0%) of those who received adagrasib monotherapy. No Grade 5 TRAEs were observed in either treatment arm."Adagrasib represents Mirati's scientific commitment to the discovery and development of novel targets that may lead to new treatment options for people with cancer," said Charles M. Baum, M.D., Ph.D., president and chief executive officer, Mirati Therapeutics, Inc. "The results presented at ESMO support further study of adagrasib in KRAS-mutated colon cancer, including with our ongoing, global registrational Phase 3 trial, KRYSTAL10, comparing adagrasib plus cetuximab to standard of care chemotherapy in second-line KRASG12C-mutated colorectal cancer."

Virtual Investor Event

Mirati Therapeutics will host a virtual Investor Event on Monday, September 20, 2021 at 8:30 a.m. ET / 5:30 a.m. PT.

Company executives will discuss:

A top-line update from the Phase 2 registrational cohort of the KRYSTAL-1 study evaluating adagrasib in previously-treated patients with KRASG12C-mutated non-small cell lung cancer (NSCLC)

Findings from the CRC cohort of the Phase 1/2 KRYSTAL-1 study evaluating adagrasib as monotherapy and in combination with cetuximab in patients with heavily pretreated CRC harboring the KRASG12C mutation, as presented at the 2021 ESMO Congress

Results from the Phase 2 MRTX-500 study evaluating sitravatinib combined with nivolumab in patients with non-squamous NSCLC who progressed on or after prior checkpoint inhibitor therapy, to be presented at the 2021 ESMO CongressInvestors and the general public are invited to register and listen to a live webcast of the event through the "Investors and Media" section on Mirati.com. A replay of the event will be available shortly after the conclusion of the event.