Cancer Drugs: Pembrolizumab Approved By US FDA As First-Line Treatment For Colorectal Cancer After Positive Phase 3 Clinical Trial Results
: Pembrolizumab, an immunotherapy drug has been recently approved by the U.S. FDA as a first-line treatment for patients with certain types of advanced colorectal cancer. This is the 9th FDA approval supported by Stand Up To Cancer® (SU2C) research.
Individuals newly diagnosed with advanced or metastatic microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) colorectal cancer previously would have been prescribed pembrolizumab only after exhausting standard chemotherapy treatments.
The U.S. FDA approved pembrolizumab, also known under the brand name Keytruda, as first-line treatment for metastatic MSI-H--dMMR colorectal cancer based on early results from a phase III clinical trial, which was partially funded by an SU2C grant.
The results of the phase 3, open-label clinical trial are published in the peer reviewed journal: The New England Journal of Medicine. https://www.nejm.org/doi/10.1056/NEJMoa2017699
Dr Luis A. Diaz, MD, Head of the Division of Solid Tumor Oncology, Memorial Sloan Kettering Cancer Center, Leader of the SU2C Colorectal Cancer Dream Team told Thailand Medical News, “It was found that when compared to traditional treatment, pembrolizumab was superior with fewer side effects for MSI-H--dMMR colorectal patients. There are other solid tumor cancers in adults and children that have these same MSI-H--dMMR defects, so our research may also have ramifications for other cancer types.”
It is estimated that Around 4-5% of metastatic cancer tumors have MSI-H--dMMR biomarkers, which result from the inability of cells to repair mistakes made during the cellular division process and can lead to more tumor development.
The clinical trial involved 307 MSI-H--dMMR colorectal cancer patients in 23 countries who were treated either with pembrolizumab or standard chemotherapy.
Pembrolizumab targets and blocks a protein called PD-1 that can prevent immune cells called T cells from eliminating cancer cells effectively.
The study team found that MSI-H--dMMR colorectal cancer patients treated with pembrolizumab didn't see their cancer spread for a median 16.5 months, compared to patients treated with standard chemotherapy who saw their tumors grow after a median 8.2 months.
An overall response (complete or partial response), as evaluated with Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1, was observed in 43.8% of the patients in the pembrolizumab group and 33.1% in the chemotherapy group. Among patients with an overall response, 83% in the pembrolizumab group, as compared with 35% of patients in the chemotherapy group, had ongoing responses at 24 months. Treatment-related adverse events of grade 3 or higher occurred in 22% of the patients in the pembrolizumab group, as compared with 66% (including one patient who died) in the chemotherapy group.
It was also found that patients receiving standard chemotherapy also had more severe side effects than patients receiving pembrolizumab.
Nobel laureate Dr Phillip A. Sharp, PhD, chair of Stand Up To Cancer's Scientific Advisory Committee and an Institute professor at the David H. Koch Institute for Integr
ative Cancer Research at Massachusetts Institute of Technology told Thailand Medical News, "The Stand Up To Cancer Colorectal Cancer Dream Team has made a significant contribution to an improved treatment option for MSI-H--dMMR colorectal patients," "This is a great example of how Stand Up To Cancer's collaborative research model has a direct impact on cancer patients' lives."
To date, colorectal cancer is the second most common cause of cancer death among American men and women combined and nearly 148,000 Americans will receive a new diagnosis of colon or rectal cancer in 2020.
Although colorectal cancer death rates have declined significantly due to increased screening and improvements in treatment, about 1 in 3 adults age 50 or older do not get the recommended screening.
Alarmingly new cases of colorectal cancer are occurring at a growing rate among young and middle-aged adults in the US, with the number of cases of colorectal cancer in people under 50 expected to almost double by 2030.
Also as colorectal cancer continues to disproportionately impact people of color (Black people have the highest rates of colorectal cancer of any racial or ethnic group in the US), improvements in screening and new precision and targeted treatments must reach all patients. SU2C announced a Health Equity Initiative in January 2020.
This new initiative requires all future teams seeking Stand Up To Cancer funding to address recruitment and retention of patients from different ethnic and racial groups and underserved communities to improve diverse participation in cancer clinical trials.
The new cancer initiative also includes collaborations with advocacy groups and industry and corporate supporters to move research and public awareness efforts forward.
The study team concluded, “Pembrolizumab led to significantly longer progression-free survival than chemotherapy when received as first-line therapy for MSI-H–dMMR metastatic colorectal cancer, with fewer treatment-related adverse events.”
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