Isoprene Pharmaceuticals Secures $1.02M NCI Grant to Advance Dual-Targeting Molecular Glue Degrader for Castration-Resistant Prostate Cancer
核心洞察
Isoprene Pharmaceuticals received a $1.02 million NCI SBIR R44 Direct-to-Phase II grant to complete IND-enabling preclinical studies for VNPP433-3β (搜索), an oral molecular glue degrader.
VNPP433-3β (搜索) uniquely targets both androgen receptor (搜索) splice variants including AR-V7 and the Mnk1/2 (搜索)-eIF4E (搜索) translation initiation pathway to counter compensatory resistance mechanisms.
Preclinical data showed four-fold enhanced potency with hydrochloride salt forms against enzalutamide-resistant CWR22Rv1 xenografts, with activity superior to both enzalutamide and docetaxel.
Baltimore-based Isoprene Pharmaceuticals, Inc. (搜索) has been awarded a $1.02 million National Cancer Institute (NCI) Small Business Innovation Research (SBIR) R44 grant to advance VNPP433-3β (搜索), an orally bioavailable small molecule degrader designed to overcome resistance in prostate cancer (搜索) through a dual-targeting mechanism. The Direct-to-Phase II award will fund the completion of IND-enabling preclinical studies, positioning the compound for first-in-human clinical trials.
The grant, structured as a Direct-to-Phase II SBIR continuation, reflects the NCI's confidence in the preclinical data package assembled to date. That package includes compelling xenograft efficacy results against the enzalutamide (Xtandi)-resistant CWR22Rv1 prostate cancer (搜索) model, a widely used system for evaluating next-generation androgen receptor (搜索)-targeted therapies.
Dual Degradation: A Differentiated Mechanism
VNPP433-3β (搜索) functions as a molecular glue degrader, a modality distinct from both conventional small molecule inhibitors and the more structurally complex proteolysis-targeting chimeras (PROTACs). The compound induces ubiquitin-mediated proteasomal degradation of full-length androgen receptor (搜索) (AR) and its clinically significant splice variants — most notably AR-V7, a well-validated driver of resistance to current AR-targeted agents. Simultaneously, VNPP433-3β degrades Mnk1/2 (搜索) kinases, which regulate cap-dependent translation through phosphorylation of eIF4E (搜索).
This concurrent suppression of two pathways is designed to limit the compensatory signaling that frequently undermines single-target androgen receptor (搜索) therapies. While enzalutamide, apalutamide, and darolutamide dominate the current AR inhibitor landscape, none address the Mnk1/2 (搜索)-eIF4E (搜索) axis — a distinction that could prove clinically meaningful if the preclinical profile translates to patients.
Preclinical Efficacy and Safety Signals
Preclinical data reported by Isoprene demonstrated that hydrochloride salt forms of VNPP433-3β (搜索) achieved four-fold enhanced potency against CWR22Rv1 xenografts compared to earlier formulations, with no apparent host toxicity observed. In those same models, the compound exhibited activity superior to both enzalutamide and docetaxel (Taxotere), two standard-of-care agents in the prostate cancer (搜索) treatment paradigm.
Path Toward the Clinic
The NCI-funded work is organized around three specific aims. First, the synthesis of 500 grams of non-GMP material to support formulation development and salt-form selection. Second, ancillary pharmacology studies in prostate cancer (搜索) in vitro and in vivo models. Third, GLP toxicology and toxicokinetics studies in two animal species to support an Investigational New Drug (IND) filing with the FDA and to define a safe starting dose for first-in-human Phase I trials.
The program is led by principal investigators Vincent Njar and Vidya P. Ramamurthy.
Competitive Context
The AR-targeting field in prostate cancer (搜索) is mature, with degrader-based approaches — including PROTACs directed at AR — now in early clinical development at multiple companies. VNPP433-3β (搜索) enters this landscape with a mechanistic differentiator: the concurrent degradation of Mnk1/2 (搜索), a target not addressed by any currently approved agent. The SBIR funding mechanism situates the program within the NIH's broader infrastructure for supporting early-stage oncology drug development at smaller biotechnology companies advancing novel small molecule modalities toward clinical entry.