At the annual meeting of the American Society of Clinical Oncology (ASCO), they announced that combining the histone deacetylase inhibitor tucidinostat with standard R-CHOP chemotherapy in previously untreated “double-expresser” patients improved complete response and event-free survival (EFS) rates over R-CHOP alone.
The trial, dubbed DEB, is the first phase 3 investigation to confirm the benefit of combination treatment with an epigenetic agent for such patients, lead investigator and study presenter Weili Zhao, MD, PhD, a hematologist at the Shanghai Institute of Hematology, told her audience.
“Tucidinostat plus R-CHOP could be a new frontline treatment option in this patient population,” Dr. Zhao said.
However, the agent is not available in the United States, at least for now. It is approved in China for peripheral T-cell lymphoma (PTCL) and HER2-negative breast cancer and in Japan for PTCL and adult T-cell leukemia/lymphoma.
Dr. Zhao said that tucidinostat was also conditionally approved for DLBCL in China recently, based on the strength of the DEB results.
Study discussant Peter Riedell, MD, a hematologist at the University of Chicago, Illinois, was cautious on several points.
First, there’s been no overall survival benefit in the trial, but follow-up so far has been short, at a median of 13.9 months, and Dr. Zhao reported interim, not final, results.
Dr. Riedell also noted that there were more grade 3 or worse adverse events, particularly hematologic side effects, hypokalemia, and pneumonia, with tucidinostat add-on in DEB.
Other outstanding questions include the applicability of the findings to non-Chinese patients and the effect of adding tucidinostat to another common DLCBL chemotherapy regimen, pola-R-CHP, which is being increasingly used in the United States for higher-risk disease, which includes double-expressers of the MYC and BCLC oncogenes.
DEB equally randomized 423 patients at 40 centers in China to either six cycles of R-CHOP with tucidinostat 20 μg twice weekly or R-CHOP with placebo. Complete responders went on to either tucidinostat or placebo maintenance treatment for up to 24 weeks. Subjects had an International Prognostic Index score of at least 2.
Out of a total of 152 EFS events, 64 (30.3%) were in the tucidinostat group and 88 (41.5%) were in the placebo group; 24-month EFS was 58.9% with tucidinostat and 46.2% with R-CHOP alone (hazard ratio, 0.68; P = .018).
Meanwhile, the complete response rate with tucidinostat was 73.0% versus 61.8% (P = .014).
Although there were more higher-grade adverse events in the experimental arm, most patients were able to tolerate and complete the planned treatment cycles.
The study was funded by tucidinostat maker Chipscreen Biosciences. Dr. Zhao reported no disclosures. Dr. Riedell disclosed ties with numerous companies, including BeiGene (a partner of Chipscreen) and Novartis.