Roche to develop new dMMR pan-cancer test for Merck’s Keytruda immunotherapy

Colorectal cancer cells staining positive for dMMR under Roche's Ventana panel (Roche)

If you can’t beat 'em, join 'em: Roche is teaming up with its immuno-oncology competitor Merck & Co. to develop a pan-cancer companion diagnostic test for its Keytruda therapy aimed at detecting the mismatch repair deficiency biomarker, or dMMR, in solid tumors regardless of their location.

Roche said in a statement that it plans to pursue an FDA approval for the immunohistochemistry assay to provide a standardized predictive testing option for dMMR.

Keytruda was the first cancer treatment granted a site-agnostic approval by the FDA, handed down in May 2017 for patients with microsatellite instability-high or mismatch repair deficient solid tumors that have no alternative treatment options.

Currently, clinical testing for dMMR biomarker status is used to help identify patients that may have a genetic disposition for colorectal and other cancers, known as Lynch syndrome, by screening for four related proteins alongside a BRAF V600E genetic mutation.

The collaboration between Merck and Roche hopes to expand the biomarker panel’s use to help select patients with solid tumors for immunotherapy. The new diagnostic test is being developed for Roche’s BenchMark Ultra platform.

RELATED: Merck beats out Roche with yet another Keytruda lung cancer approval

Elsewhere, Roche has put up its own immunotherapy to compete against Merck and its blockbuster Keytruda—with an FDA approval just last week of a regimen combining its anti-PD-L1 drug Tecentriq with Avastin and chemotherapy, in first-line non-small cell lung cancer without EGFR or ALK mutations.

But Keytruda’s two-drug chemotherapy combination has a long head start in the lucrative market, with an analyst predicting Merck will hold at No. 1 followed by Roche at No. 2, with Tecentriq’s sales peaking at just over $1.5 billion in the indication.

And in August, the FDA expanded Keytruda’s label to include data showing that, when combined with Eli Lilly’s Alimta and platinum chemotherapy, it could cut the risk of death by half compared to chemotherapy alone in untreated NSCLC.

RELATED: The day has come: Merck’s Keytruda surpasses Bristol-Myers Squibb’s Opdivo in Q2 sales

Meanwhile, Bristol-Myers Squibb is also aiming to move further into colorectal cancers identified as microsatellite instability-high or mismatch repair deficient. At the annual meeting of the European Society for Medical Oncology this October, BMS’ Opdivo immunotherapy demonstrated responses in 60% of previously untreated patients in a phase 2 trial.

Opdivo received the second FDA approval in microsatellite instability-high tumors in August 2017, though its scope was limited to metastatic colorectal cancer.