FDA Approves New Companion Dx, Advancing Precision in Colorectal Cancer

In a step for personalized cancer care, the US FDA has approved Agilent Technologies Inc's MMR IHC Panel pharmDx (Dako Omnis), a new companion diagnostic (CDx) test for colorectal cancer (CRC).¹ This approval is poised to provide oncologists and pathologists with an essential tool for identifying patients who will most likely benefit from specific immunotherapy treatments.

The test is designed to detect mismatch repair deficient (dMMR) tumors, guiding the use of nivolumab (Opdivo) as a monotherapy or in combination with ipilimumab (Yervoy). The approval of this diagnostic, for exclusive use with the Agilent Dako Omnis automated staining solution, underscores the growing importance of biomarkers in tailoring treatment strategies.

MMR is a critical cellular pathway that corrects DNA replication errors, thereby maintaining genomic stability. dMMR tumors are characterized by a high number of mutations, making them particularly susceptible to immune checkpoint inhibitors. The Agilent panel is the only FDA-approved immunohistochemical (IHC) companion diagnostic for this specific purpose, providing a standardized and validated method for identifying patients for nivolumab and nivolumab/ipilimumab regimens.

"This approval marks an important step forward in the ongoing effort to improve colorectal cancer care," said Nina Green, vice president and general manager of Agilent’s Clinical Diagnostics Division, in a press release. "Our new CDx product offers [health care] providers an additional tool to identify mismatch repair deficiency in patients, complementing existing options and enhancing the ability to tailor immunotherapy treatments. By providing more choices, we aim to support better tumor control and potentially improve progression-free survival, ultimately contributing to patient care and well-being."

The clinical validation of nivolumab and nivolumab/ipilimumab for dMMR CRC has been demonstrated through key clinical trials. For example, the FDA's accelerated approval of nivolumab alone for dMMR metastatic CRC was based on data from the CheckMate-142 trial (NCT02060188), which showed a durable response in patients with heavily pretreated disease.² Subsequent studies, including CheckMate-8HW (NCT04008030), further established the combination of nivolumab and ipilimumab as a highly effective first-line treatment for these patients, demonstrating superior progression-free survival compared to chemotherapy.³ The ability to accurately and efficiently identify patients with dMMR status is therefore paramount to leveraging the full potential of these immunotherapies.

What is the Agilent IHC Panel pharmDx?

The Agilent Technologies IHC Panel pharmDx is a companion diagnostic test designed for CRC. It helps oncologists and pathologists identify patients who are most likely to benefit from specific immunotherapy treatments like nivolumab and ipilimumab.

The MMR IHC Panel pharmDx streamlines the testing process by detecting the loss of function of 4 key MMR proteins:

• MLH1
• PMS2
• MSH2
• MSH6

This is done in formalin-fixed paraffin-embedded (FFPE) CRC tissue. This is a crucial step in the clinical workflow, as it provides definitive information that informs treatment decisions.

FAQs

What is the new FDA-approved companion diagnostic for colorectal cancer?

The new FDA-approved companion diagnostic is Agilent Technologies Inc.'s MMR IHC Panel pharmDx (Dako Omnis). It is a diagnostic test specifically designed for colorectal cancer (CRC) to identify patients who are most likely to benefit from certain immunotherapy treatments.

How does the Agilent MMR IHC Panel pharmDx work?

This companion diagnostic works by detecting mismatch repair deficient (dMMR) tumors. It specifically identifies the loss of function of four key mismatch repair (MMR) proteins: MLH1, PMS2, MSH2, and MSH6, in formalin-fixed paraffin-embedded (FFPE) CRC tissue. This process provides crucial information for guiding treatment decisions.

Why is identifying dMMR tumors important for colorectal cancer treatment?

MMR is a vital cellular pathway that corrects DNA replication errors, ensuring genomic stability. Tumors with dMMR are characterized by a high number of mutations, making them particularly susceptible to immune checkpoint inhibitors. Identifying these tumors is paramount because it allows healthcare providers to tailor immunotherapy treatments, such as nivolumab (Opdivo) and ipilimumab (Yervoy), which have shown significant effectiveness in dMMR CRC patients.

Is the Agilent MMR IHC Panel pharmDx the only FDA-approved test of its kind?

Yes, the Agilent MMR IHC Panel pharmDx is currently the only FDA-approved immunohistochemical (IHC) companion diagnostic for the specific purpose of identifying patients for nivolumab and nivolumab/ipilimumab regimens in colorectal cancer. This provides a standardized and validated method for this identification.

How does this new companion diagnostic enhance immunotherapy outcomes for colorectal cancer patients?

By accurately identifying dMMR tumors, the Agilent MMR IHC Panel pharmDx enables healthcare providers to personalize treatment strategies. This precision in diagnosis allows for the targeted use of immunotherapies like nivolumab and nivolumab/ipilimumab, which have been shown in clinical trials to lead to durable responses and superior progression-free survival compared to chemotherapy in patients with dMMR CRC. This contributes to better tumor control and potentially improved patient well-being.

REFERENCES:

1. Agilent MMR IHC Panel pharmDx (Dako Omnis) Receives FDA Approval as a Companion Diagnostic Test for Colorectal Cancer. News release. Agilent Technologies. August 20, 2025. Accessed August 20, 2025. https://tinyurl.com/32re4ksw

2. FDA grants accelerated approval to ipilimumab for MSI-H or dMMR metastatic colorectal cancer. News release. US FDA. July 11, 2018. Accessed August 20, 2025. https://tinyurl.com/3bnrnad9

3. Bristol Myers Squibb announces phase 3 CheckMate-8HW trial evaluating Opdivo (nivolumab) plus Yervoy (ipilimumab) compared to chemotherapy in microsatellite instability-high or mismatch repair deficient metastatic colorectal cancer meets primary. News release. Bristol Myers Squibb. December 7, 2023. Accessed August 20, 2025. https://tinyurl.com/52p53ath

This was created with assistance from Google Gemini and NotebookLM. The content has been reviewed and edited by Targeted Oncology staff. For more information on the extent and nature of AI usage, please contact us.