This treatment has achieved a disease control rate of up to 90% in patients with colorectal cancer

• by EVOMT
• 2017-06-05

　　In 2017, a study was released at the American Gastrointestinal Cancer Symposium, which showed that immunotherapy combined with targeted therapy for MSI-H (highly microsatellite unstable) achieved an overall remission rate of 40% (RECIST standard) or 30% (irRC standard) for metastaticfile colorectal cancer, and a disease control rate of 90%.

　　In this study, 10 patients were treated with atezolizumab (Tecentraq) combined with bevacizumab (Avastin). Among them, 4 patients achieved partial remission, 5 patients achieved disease stability, and the overall disease control rate reached 90%. The average follow-up period was 14.8 months. No median remission duration and median disease progression free survival data have been obtained. Two patients experienced treatment related adverse events at level 3 or 4. Four patients were suspended due to adverse reactions, of which 3 were associated with bevacizumab and 1 was associated with atezolizumab.

　　"The first author of the study, Professor Howard S. Hochster from the Yale University School of Medicine, said:“ The combination of atezolizumab and bevacizumab is well tolerated and relatively safe for patients. For patients with MSI-H metastaticfile colorectal cancer who have previously undergone multiple treatments, the combination of the two drugs has demonstrated excellent antitumor activity. "The efficacy is long-lasting, with an average duration of efficacy exceeding 12 months, and researchers are still conducting further follow-up visits to these patients”";

　　Professor Howard S. Hochster

　　Patients with refractory colorectal cancer have a poor prognosis. In a randomized clinical trial, the median survival time of patients using the small molecule inhibitor regorafenib (Stivarga) was 6.4 months, only 1.4 months longer than those receiving placebo. In this trial conducted by Professor Hochster, a total of 10 patients with MSI-H metastaticfile colorectal cancer were included to observe the safety and drug response after using atezolizumab and bevacizumab. The main purpose is to obtain data on the safety and tolerability of dual drug combinations, while the secondary purpose includes obtaining the antitumor activity of dual drug combinations under the RECIST and IRRC standards.

　　The average age of patients participating in the clinical trial was 52.5 years old, with an ECOG score of 0-1. Seven of the patients had previously received more than two treatments, nine had received platinum based chemotherapy, seven had previously used bevacizumab, and eight of the 10 had tumors located on the right.

　　If the RECIST standard and the IRRC standard are used simultaneously, the combination of the two drugs enables the condition of 9 patients to be controlled (including remission and disease stabilization). Under the RECIST standard, 4 patients achieved partial remission, 5 patients were stable, with an effective duration range of 1.6 to 12.4 months, and a progression free survival range of 1.5 to 21.9 months. Under irRC criteria, 3 patients achieved partial remission, 6 patients were stable, with an effective duration of 7.8-12.4 months, and a progression free survival period of 2.6-23.7 months.

　　The most common adverse reactions include fatigue, diarrhea, proteinuria, joint pain, and sinusitis, anemia, hypertension, hypokalemia, and peripheral edema, nausea, non cardiovascular chest pain, small intestinal obstruction, abdominal pain, anxiety, back pain, constipation, low back pain, muscle spasms, nasopharyngitis, itching, vomiting, and weight loss. Grade 3/4 adverse reactions include proteinuria, anemia, hypertension, hypokalemia, nausea, non cardiac chest pain, and small intestinal obstruction.

　　MSI (Microsatellite Instability) refers to the accumulation of mutations formed during DNA synthesis. Often due to a lack of mismatch repair proteins, approximately 4% of patients have a high MSI phenotype. Studies have shown that patients with colorectal cancer who lack mismatch repair protein use PD-1 inhibitors more effectively than other patients.

　　Bevaczumab is an angiogenesis inhibitor that targets vascular epithelial growth factors, which play an important role in immune escape. Research on tumor therapy has shown that anti vascular therapy can improve the efficacy of immunotherapy. The drug was also approved by the FDA for the treatment of metastaticfile colorectal cancer in 2004.