Novel phase 1a/1b dose-finding study design of CWP232291 (CWP291) in relapsed or refractory myeloma (MM).

Abstract

TPS8058 Background: CWP291, a novel peptidomimetic small molecule, has potent, selective inhibitory activity on a Wnt gene reporter, decreasing expression of β-catenin target genes, cyclin D1 and survivin. With broad anti-cancer efficacy in vitro, it significantly outperforms lenalidomide as a single agent combination in MM bone marrow engraftment models. Methods: This Phase 1a/1b study (NCT #02426723) was designed to define a well-tolerated dose of CWP291 as a single agent in subjects with R/R MM. CWP291 was administered IV over ≥30 minutes 2x weekly for 3 weeks out of a 4-week cycle, with standard 3+3 dose escalation design. But an important objective in terms of patient benefit and further clinical development was to explore activity of a combination regimen with lenalidomide. Thus, a novel study design allowed initiation of the Phase 1b as soon as CWP291 achieved a well-tolerated dose as a single agent. Combination therapy would start at one dose level lower. Enrollment of patients onto each arm was guided by Safety Review Committee assessments, including baseline laboratory values, performance status, extent of prior therapy, or prior adverse events related to lenalidomide. Results: Initiated September 2015, the starting dose was based on a prior Phase 1 study in AML, 198 mg/m2. There were 4 sites involved, and 11 patients enrolled over 12 months. Approval of the new design by regulatory authorities and IRBs was completed by November 2016. A well-tolerated single agent dose (297 mg/m2) was identified, allowing initiation of the Phase 1b at a dose of 198 mg/m2(one dose level lower) combined with lenalidomide. Four subjects were enrolled in ~2 months to the Phase 1b. Enrollment to both arms is continuing and the status of this study will be updated at presentation. Conclusions: The ability to consider combination therapy with a novel drug is clearly a motivation for patient participation in clinical trials; especially true in MM, as multiple new therapies are available. This trial design was approved and allowed based on assessment of individual patient safety and potential benefit. Rapid enrollment in the combination therapy arm may significantly foster development of novel agents with this study design. Clinical trial information: NCT #02426723.