A recent clinical trial has shown promising results in treating mismatch repair deficient (dMMR) tumors with high microsatellite instability (MSI-H) using immunotherapy drug pembrolizumab before surgery instead of chemotherapy for people with stage two or three colorectal cancer. This innovative approach has been found to significantly improve outcomes for patients with this specific type of colorectal cancer, which accounts for about 15% of all cases. The study was presented at the American Society of Clinical Oncology (ASCO) Annual Meeting 2024. Researchers administered three cycles of pembrolizumab before surgery, leading to more than 50% of patients having no signs of cancer after their surgery, a marked improvement compared to standard chemotherapy.
Colorectal cancer, also known as colon cancer or bowel cancer, is a prevalent type of cancer globally, with more than 1.9 million cases diagnosed in 2020 and expected to rise to 3.2 million by 2040. MMR deficient/MSI-H colorectal cancer tumors can be challenging to treat, but the use of pembrolizumab before surgery has shown promising results in improving outcomes for patients with stage two or three colorectal cancer. Pembrolizumab, an immunotherapy drug, works by upregulating the patient’s immune system to recognize and eliminate cancer cells. This approach has been particularly successful in treating deficient dMMR bowel cancers, with the potential to induce long-term remission and even cure, unlike traditional non-targeted treatments like chemotherapy and radiotherapy.
The NEOPRISM-CRC phase II clinical trial focused on pembrolizumab, and the results indicated that giving immunotherapy before surgery can lead to a more significant number of patients being cancer-free post-surgery compared to those receiving chemotherapy. This novel approach aims to shrink the cancer significantly before surgery, potentially eliminating microscopic cancer cells that could lead to future relapse. The study’s primary endpoint is three-year relapse survival rate, with researchers looking to enroll more patients to generate sufficient data and confidence in the effectiveness and long-term benefits of this treatment.
The results of the clinical trial have garnered interest from experts in the field, with Dr. Anton Bilchik highlighting the novel and provocative nature of the study. Immunotherapy has traditionally been used in advanced colon cancer, but this study is the first to explore its efficacy in the early stages of colon cancer before surgery. Dr. Glenn S. Parker emphasized the importance of long-term follow-up to assess the duration of response and cautioned that the promising results of immunotherapy cannot be generalized to all colon cancers. However, with the development of more drugs for both chemotherapy and immunotherapy, future clinical trials will continue to shape individualized treatment strategies based on the molecular genetic profile of patients and their tumors.
Overall, the use of pembrolizumab before surgery in patients with MMR deficient/MSI-H colorectal cancer represents a significant advancement in the treatment of this specific subtype of colorectal cancer. The promising results of the NEOPRISM-CRC trial point towards a potential shift in treatment approaches, focusing on immunotherapy to induce remission and possibly cure patients upfront. As research continues to unravel the nuances of immunotherapy and its efficacy in different cancer types, personalized treatment strategies are likely to play a significant role in shaping the future of cancer care.
