Seattle Genetics Inc. said its drug tucatinib, combined with Roche Holding AG's Herceptin, shrank tumors in colorectal cancer patients in a mid-stage study.
The phase 2 trial, called Mountaineer, is evaluating the combination in patients with HER2-positive, RAS wild-type colorectal cancer which has spread across the body. Patients under the trial have also been previously treated with first-line and second-line standard-of-care therapies.
Objective response rate — a measure of how much a tumor was reduced in size after therapy — was 52.2% among 23 evaluable patients, according to interim data presented at the European Society for Medical Oncology's 2019 scientific meeting.
Median progression-free survival, or the length of time a patient stays alive without the disease worsening, was 8.1 months. Meanwhile, median overall survival — the period of time a patients stays alive with the disease — was 18.7 months.
The combination of tucatinib and Herceptin was also well tolerated by patients, with the most common treatment-related adverse events belonging to the lowest grade.
Colorectal cancer is the second-leading cause of cancer death in the U.S. The National Cancer Institute estimates about 145,600 new cases and 51,020 deaths from colorectal cancer in the U.S. in 2019.
Bothell, Wash.-based Seattle Genetics acquired tucatinib when it bought Cascadian Therapeutics Inc. for $614 million in 2018.
The European Society for Medical Oncology is holding its 2019 scientific meeting in Barcelona, where more than 3,900 study abstracts have been submitted for review by oncology professionals from around the world.
