Combination epigenetic therapy in metastatic colorectal cancer (mCRC) with subcutaneous 5-azacitidine and entinostat; a phase 2 consortium/stand Up 2 cancer study
Colorectal cancer; DNA methyltransferases inhibitors; Epigenetics; Histone deacetylase inhibitors
© Azad et al. Purpose: Therapy with demethylating agent 5-azacitidine and histone deacetylase inhibitor entinostat shows synergistic re-expression of tumor-suppressor genes and growth inhibition in colorectal (CRC) cell lines and in vivo studies. Experimental Design: We conducted a phase II, multi-institutional study of the combination in metastatic CRC patients. Subcutaneous azacitidine was administered at 40 mg/m2 days 1-5 and 8-10 and entinostat was given 7 mg orally on days 3 and 10. An interim analysis indicated toxicity crossed the pre-specified safety boundary but was secondary to disease. A 2nd cohort with added eligibility restrictions was accrued: prior therapies were limited to no more than 2 or 3 (KRAS-mutated and KRAS-wildtype cancers, respectively) and < 30% of liver involvement. The primary endpoint was RECIST response. Serial biopsies were performed at baseline and after 2 cycles of therapy. Results: Forty-seven patients were enrolled (24:Cohort 1, 23:Cohort 2). Patients were heavily pre-treated (median prior therapies 4: Cohort 1 and 2.5: cohort 2). No responses were observed. Median progression-free survival was 1.9 months; overall survival was 5.6 and 8.3 months in Cohorts 1 and 2, respectively. Toxicity was tolerable and as expected. Unsupervised cluster analysis of serial tumor biopsies suggested greater DNA demethylation in patients with PFS above the median. Conclusion: In this first trial of CRC patients with combination epigenetic therapy, we show tolerable therapy without significant clinical activity as determined by RECIST responses. Reversal of hypermethylation was seen in a subset of patients and correlated with improved PFS.
Azad, N., El-Khoueiry, A., Yin, J., Oberg, A., Flynn, P., Adkins, D., Sharma, A., Weisenberger, D., Brown, T., Medvari, P., Jones, P., Easwaran, H., Kamel, I., Bahary, N., Kim, G., Picus, J., Pitot, H., Erlichman, C., Donehower, R., Shen, H., Laird, P., Piekarz, R., Baylin, S., & Ahuja, N. (2017). Combination epigenetic therapy in metastatic colorectal cancer (mCRC) with subcutaneous 5-azacitidine and entinostat; a phase 2 consortium/stand Up 2 cancer study. Oncotarget, 8 (21). http://dx.doi.org/10.18632/oncotarget.15108