FDA Speeds Up Review of Tukysa Plus Herceptin for Metastatic Colon Cancer

The Food and Drug Administration (FDA) granted a priority review to Tukysa (tucatinib) plus Herceptin (trastuzumab) for the treatment of previously treated patients with HER2-positive unresectable (unable to be removed surgically) or metastatic colorectal cancer, according to Seagen, the manufacturer of Tukysa.

In granting the priority review, the FDA agrees to speed up the development and review of the drug, because the agency decided that the treatment showed promise in a clinical trial. In this case, the trial was the phase 2 MOUNTAINEER study, whose results were presented at the European Society for Medical Oncology Congress on Gastrointestinal Cancers in July.

“There are currently no FDA-approved therapies for metastatic colorectal cancer that specifically target HER2,” Dr. Marjorie Green, senior vice president and head of Late-Stage Development, Seagen, said in a company-issued press release. “The FDA’s prioritization of our application for (Tukysa) in combination with (Herceptin) supports our belief in its significant potential to benefit people with previously treated HER2-positive metastatic colorectal cancer.”

Results from MOUNTAINEER showed that at an average follow-up of 20.7 months, 38.1% of patients administered Tukysa plus Herceptin had their disease shrink. The average duration of response was 12.4 months.

Average progression-free survival (time from treatment until disease worsens) was 8.2 months for patients given the drug combination, and average overall survival (time from treatment until death of any cause) was 24.1 months.

The FDA plans to make an approval decision on Tukysa plus Herceptin for adults with unresectable or metastatic, HER2-positive colorectal cancer who have previously been treated with fluoropyrimidine-, oxaliplatin- and irinotecan-containing chemotherapy, by Jan. 19, 2023. However, the agency can decide to expedite or delay their decision.

Tukysa will continue to be studied in the phase 3 MOUNTAINEER-03 clinical trial, which launched in February 2022, and is evaluating the drug with Herceptin and standard chemotherapy for the frontline treatment of HER2-positive metastatic colorectal cancer.

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