Patients with colorectal cancer showed improved survival outcomes with Pembrolizumab immunotherapy , with over 50% showing cancer-free post-surgical results, recommending further patient recruitment for relapse-free survival.

June 6, 2024: A new clinical trial reveals significantly improved survival outcomes for colorectal cancer patients who have dMMR with MSI-H after administration of immunotherapy pembrolizumab (Keytruda).

• Key Findings Participants: 32 patients with stage two or 3 dMMR/MSI-H colorectal cancer to receive atezolizumab in combination with normal amounts of chemotherapy.
• Treatment: Two cycles of pembrolizumab are given prior to surgery, and another one is given prior to neoadjuvant therapy.
• Results: That is, over 50% of participants demonstrated cancer-free post-surgical results while requiring only 4% of patients to undergo pre-surgical chemotherapy.

Study Details Background

• MMR Deficiency: This is a failure of the normal process through which errors that result from DNA replication are corrected, leading to more microsatellite instability and tumor formation.
• Immunotherapy Mechanism: Pembrolizumab is an immune checkpoint inhibitor that can improve the immune system’s ability to detect and target cancer cells.

Clinical Trial

• Frequency: Patients consumed the experimental drug, PEMBROLIZUMAB, in three-week cycles before the surgery.
• Outcome: Only 10% of the patients in the study had residual tumor cells after surgery, showing how successful pembrolizumab is in shrinking and eradicating the remainder of cancer cells that are often too small to detect.

Expert Opinions

• Dr. Kai-Keen Shiu: Pembrolizumab works by enhancing the immune system, hence long-term remission after the treatment period
• Dr. Anton Bilchik: “This is a unique study that shows high percentage node-negative, early-stage patients with no tumors after surgery.”

Future directions

• More Patient Recruitment: The research team hopes to recruit more patients to ensure a three-year relapse-free survival.
• Biological Insights: Further studies are needed to advance immunotherapy knowledge and map an individual’s tumor's specific characteristics so treatments could be adjusted according to the specificities.

Conclusion

Pembrolizumab is a novel non-surgical approach for mCRC, which might change the traditional management strategy for patients with dMMR/MSI-H tumors.