A phase 2 trial combining two Bristol-Myers Squibb Co. cancer treatments achieved a 60% intracranial clinical benefit rate, or IC CBR, in patients with melanoma metastatic to the brain.

The company was evaluating a combination of Opdivo with Yervoy in 75 patients, and the data is from the median follow-up of 9.2 months.

Intracranial clinical benefit rate is defined as a combination of patients that achieved a complete response, those that achieved a partial response and those that experienced stable disease, evaluated at least six months after the start of the trial.

The 60% IC CBR can be broken down to 21% of patients who achieved a complete response, 33% who had partial response and 5% who experienced stable disease.

Metastatic melanoma is the deadliest form of skin cancer; it spreads beyond the surface of the skin to other organs.

Interim trials from a separate phase 2 trial evaluating the use of the immuno-oncology combination showed a 54.8% investigator-assessed objective response rate in patients with DNA mismatch repair deficient or microsatellite instability-high metastatic colorectal cancer.

The median duration of response and median overall survival for the study were not reached. The trial also evaluated Opdivo as a monotherapy in the said patient population.

DNA mismatch repair deficiency occurs when the proteins that repair mismatch errors in DNA replication are missing or nonfunctional, which leads to microsatellite instability-high tumors in certain types of cancer, including colorectal cancer, which develops in the colon or the rectum.