China Greenlights Promega's Cancer Diagnostic, Paving Way for Targeted KEYTRUDA Therapy

MADISON, WI – February 03, 2026 – In a significant move to advance personalized cancer treatment, China's National Medical Products Administration (NMPA) has granted Class III approval to Promega Corporation’s OncoMate® Microsatellite Instability (MSI) Detection Kit. The approval designates the kit as a crucial companion diagnostic for Merck’s blockbuster anti-PD-1 therapy, KEYTRUDA® (pembrolizumab), enabling doctors to identify solid tumor patients with MSI-High (MSI-H) status who are most likely to benefit from the treatment.

This landmark approval, the first of its kind for the Madison-based life sciences company in China, addresses a critical need within the nation's healthcare system. China faces one of the world's most significant cancer burdens, with an estimated 3.2 million new cases diagnosed in 2024 alone. Solid tumors represent the vast majority of these diagnoses, and for many patients with advanced disease, therapeutic options become limited after first-line treatments fail. The introduction of a validated, locally approved companion diagnostic provides a powerful tool for oncologists to guide more effective, data-driven treatment strategies.

“This approval represents a step toward more personalized and effective cancer treatment in China,” said Alok Sharma, Global Clinical Market Director at Promega, in a statement. “We are proud to collaborate with pharmaceutical companies to deliver global solutions that expand access to innovative technologies and life-saving, effective therapies.”

A New Era for Precision Oncology in China

The NMPA's decision aligns with China's ambitious 'Healthy China 2030' initiative, a national strategy focused on improving public health through measures that include early disease detection and personalized medicine. The precision oncology market in China, valued at over $5.2 billion in 2024, is forecast to nearly double to $9.6 billion by 2030, with diagnostics being its fastest-growing segment.

Microsatellite instability is a key biomarker that indicates a deficiency in a cell's ability to repair DNA errors. Tumors with this MSI-High characteristic are often more responsive to immunotherapies like KEYTRUDA, which work by unblocking the immune system’s ability to attack cancer cells. The prevalence of MSI-H varies by cancer type but is a critical factor across many solid tumors, including colorectal and gastric cancers, which are common in China. Research indicates MSI-H prevalence in Chinese colorectal cancer patients ranges from approximately 4.5% to 15%.

The OncoMate® kit is a PCR-based assay, widely considered the gold standard for MSI detection due to its high sensitivity and specificity. Its approval provides Chinese clinicians with a reliable and standardized method to determine MSI status, moving beyond less precise or non-standardized testing methods and ensuring patients receive the most appropriate care. This development is expected to accelerate the adoption of precision oncology principles in clinical practice across the country, from major urban hospitals to regional medical centers.

The Power of a Drug-Diagnostic Partnership

This approval underscores the increasingly vital synergy between diagnostic and pharmaceutical companies. The collaboration between Promega and Merck & Co., Inc., Rahway, NJ, USA, exemplifies a modern approach to cancer care where the development and approval of a therapeutic is intrinsically linked to a reliable diagnostic test. By providing a clear method to identify the patient population that will benefit most, companion diagnostics de-risk treatment, improve patient outcomes, and enhance the value proposition of targeted therapies.

For Merck, the availability of a NMPA-approved companion diagnostic strengthens the market position of KEYTRUDA in China. It facilitates broader and more appropriate use of the drug, tapping into a significant market. The market for drugs targeting MSI-H tumors in China was valued at over $150 million in 2021 and is projected to exceed $660 million by 2030, highlighting the substantial commercial and clinical opportunity.

The Chinese CDx market, while rapidly growing, is also highly competitive. Promega joins a dynamic field that includes global giants like Roche and Thermo Fisher, as well as innovative domestic players like Burning Rock Biotech and BGI Group. However, by securing a Class III designation—the highest risk category for medical devices in China—and a specific companion diagnostic label for a leading oncology drug, Promega has established a strong competitive foothold.

A Global Strategy with Local Impact

The NMPA approval is not an isolated success for Promega but rather a key milestone in its global expansion and validation of its MSI technology. The company's platform has already secured regulatory green lights in other major markets, including the European Union and the United States. Notably, the U.S. Food and Drug Administration (FDA) recently approved the OncoMate® MSI Dx Analysis System as a companion diagnostic to identify patients with microsatellite stable (MSS) endometrial carcinoma who may benefit from treatment with KEYTRUDA in combination with LENVIMA®.

This track record of successful regulatory approvals across different cancer types and jurisdictions demonstrates the robustness and versatility of Promega's underlying technology. For Chinese regulators and clinicians, this global validation provides an additional layer of confidence in the kit's performance and reliability. The OncoMate® MSI Detection Kit, which will be available for purchase in China soon, is poised to become an integral part of the country's evolving cancer treatment landscape, offering new hope to patients with advanced solid tumors and reinforcing the central role of diagnostics in the future of medicine.