A phase II study of a novel oral isotype-selective histone deacetylase (HDAC) inhibitor in patients with relapsed or refractory Hodgkin lymphoma

Abstract

8000 Background: MGCD0103 is a non-hydroxamate, isotype-selective, inhibitor of human HDACs. Abnormal regulation of HDAC activity is associated with malignant disease in humans, and small molecule HDAC inhibitors are a novel drug class with anticancer potential. Their proposed anti-Hodgkin activity is through regulation of aberrant gene expression at the transcriptional level by inhibiting proliferation, inducing apoptosis, and/or initiating differentiation in cancer cells. Methods: A phase II trial of MGCD0103 (110 mg 3x/week in 4- week cycles) is ongoing in patients (pts) with relapsed/refractory Hodgkin Lymphoma (RRHL). The primary endpoint is a composite of objective response and stable disease. Results: As of Dec 15th, 2006, 18 pts out of a planned 12–35 have been enrolled; median age 28 (range: 21–62). All pts were previously treated with autologous and/or allogeneic stem cell transplant. The median number of cycles received to date is 2 (range: 1–4). Seven pts have completed =8 weeks (2 cycles) of therapy and are evaluable for response analysis; 5 of these had tumor reduction ranging between 21% and 70% by CT, which is associated with a significant reduction in FDG-PET activity in 4 pts. Of the 18 pts, 5 have had dose reductions/discontinuations due to: mucositis (n=1); fatigue/nausea/diarrhea (n=1); nausea/vomiting (n=1); fatigue (n=1) and pancreatitis/hypotension (n=1). Significant HDAC inhibition (>20% of total activity), was seen in PBMCs from 7/9 pts with samples. Treatment is ongoing in 14 pts; including those with tumor reduction. Criteria have been met to expand to the second stage of the study (>1 response demonstrated in the first 12 patients). Conclusions: Preliminary results suggest that single-agent MGCD0103 demonstrates significant anti-tumor activity in RRHL and is well tolerated at a Phase II dose of 110mg in this ongoing trial. No significant financial relationships to disclose.