Constellation Pharmaceuticals Initiates Phase 2 Portion of ProSTAR Clinical Trial in Patients with Metastatic Castration-Resistant Prostate Cancer (mCRPC)
- Dosing has begun in a randomized study of CPI-1205 / enzalutamide combination versus enzalutamide alone in second-line mCRPC
- Single-arm CPI-1205 / abiraterone / prednisone combination added to potentially address low response rates and short duration of response in second-line mCRPC with abiraterone alone
- Preliminary Phase 1b results suggest CPI-1205 is well-tolerated, with a robust PK/PD profile and clinical activity in both arms in second-line mCRPC
The ProSTAR study is evaluating CPI-1205, Constellation’s potent and highly selective small-molecule EZH2 inhibitor, in combination with either enzalutamide or abiraterone / prednisone (“abiraterone”), in mCRPC patients who experienced disease progression while receiving the other ARS inhibitor. Based on encouraging results from the Phase 1b portion of ProSTAR, the Company has initiated dosing in the randomized Phase 2 portion studying CPI-1205 in combination with enzalutamide versus enzalutamide alone. Constellation has also decided to expand the Phase 2 portion of the study by adding an arm evaluating CPI-1205 in combination with abiraterone in the second-line setting.
“We are pleased that CPI-1205 achieved its Phase 1b endpoints in ProSTAR, demonstrating an encouraging safety profile and evidence of clinical activity in both arms,” said
Initiation and Expansion of Phase 2 Portion of ProSTAR
As planned, Constellation has already begun dosing patients in the Phase 2 portion of the study, evaluating CPI-1205 in combination with enzalutamide versus enzalutamide alone. The Company continues to expect enrollment of up to 35 patients in both the treatment and the control arms.
Additionally, Constellation is expanding the trial to include a separate Phase 2 arm evaluating CPI-1205 in combination with abiraterone in up to 30 mCRPC patients who progressed on prior enzalutamide therapy. This arm, which will soon begin dosing patients, will not be randomized against a control arm due to the low response rate and lack of durability seen with abiraterone in the second-line setting.
In a recent randomized cross-over trial, only 4% of patients taking abiraterone after disease progression on enzalutamide, and only 31% of patients taking enzalutamide after disease progression on abiraterone, achieved a 50% reduction in
Constellation continues to expect to determine proof of concept for CPI-1205 in mid-2019.
1 D. Khalaf et al, Phase 2 randomized cross-over trial of abiraterone + prednisone (ABI) vs enzalutamide (ENZ) for patients (pts) with metastatic castration resistant prostate cancer (mCRPC): results for 2nd-line therapy, poster presented at 2018
mCRPC is an advanced form of prostate cancer and is defined by disease progression despite treatment with androgen depletion therapy (ADT). mCRPC may present as one or any combination of the following: a continuous rise in serum levels of
This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 that involve substantial risks and uncertainties, including statements regarding the development status of the Company’s product candidates, the anticipated benefits of the changes to its clinical trial protocols and its anticipated achievement of milestones, including determination of proof of concept. All statements, other than statements of historical facts, contained in this press release, including statements regarding the Company’s strategy, future operations, future financial position, prospects, plans and objectives of management, are forward-looking statements. The words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “target,” “will,” “would” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking statements are based on management’s current expectations of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in, or implied by, such forward-looking statements. These risks and uncertainties include, but are not limited to, risks associated with Constellation’s ability to: obtain and maintain necessary approvals from the
MacDougall Biomedical Communications
Source: Constellation Pharmaceuticals