Keytruda is Merck’s anti-PD-1 therapy and claimed to be the first approved immunotherapy for microsatellite instability (MSI) high or mismatch repair deficient solid tumors.

The companion diagnostic tests are said to leverage FoundationOne CDx, which is Foundation Medicine’s FDA-approved comprehensive genomic profiling (CGP) assay for all solid tumors integrating multiple companion diagnostics.

The partnership will develop a pan-cancer companion diagnostic for the measurement of MSI.

In addition, the firms are planning to develop companion diagnostics for tumor mutational burden (TMB), and additional potential novel biomarkers of response.

Merck Research Laboratories oncology clinical development senior vice president Dr Eric Rubin said: “Rapidly evolving knowledge of cancer biology and immuno-oncology continues to improve understanding of how to deploy our medicines to identify those patients most likely to respond effectively.”

FoundationOne CDx assay evaluates genomic alterations in 324 genes that advance cancer growth, enabling to provide potential information to help guide treatment options.

The assay secured approval from the US Food and Drug Administration (FDA) as a broad companion diagnostic for patients with certain types of non-small cell lung cancer, melanoma, colorectal cancer, ovarian cancer or breast cancer.

FoundationOne CDx also reports genomic biomarkers such as MSI and TMB, enabling to use other targeted oncology therapies and relevant clinical trial information.

Foundation Medicine offers FoundationOne CDx assay as an FDA-approved platform for clinical research. It is also available as a CGP platform for biopharma firms that develop companion diagnostics for their precision therapeutics.

Foundation Medicine biopharma head and chief business officer Melanie Nallicheri said: “By collaborating, Merck and Foundation Medicine can continue to push the frontier on innovation in immuno-oncology and personalized cancer care, making a positive difference in the lives of individuals with cancer.”