1. PF-06952229, a selective TGF-β-R1 inhibitor: preclinical development and a first-in-human, phase I, dose-escalation study in advanced solid tumors.
- Author
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Yap, T, Choudhury, A, Hamilton, E, Rosen, L, Stratton, K, Gordon, M, Schaer, D, Liu, L, Zhang, L, Mittapalli, R, Zhong, W, Soman, N, and Tolcher, A
- Subjects
TGF-β signaling ,TGF-β-R1 inhibitor ,advanced solid tumors ,epithelial–mesenchymal transition ,metastatic castration-resistant prostate cancer ,Humans ,Male ,Middle Aged ,Aged ,Receptor ,Transforming Growth Factor-beta Type I ,Female ,Neoplasms ,Animals ,Adult ,Mice ,Antineoplastic Agents ,Dose-Response Relationship ,Drug ,Aged ,80 and over - Abstract
BACKGROUND: PF-06952229 is a selective small-molecule inhibitor of transforming growth factor-β (TGF-β) receptor 1. We evaluated its antitumor activity in preclinical studies and its safety, tolerability, pharmacokinetics, and pharmacodynamics in a phase I study (NCT03685591). PATIENTS AND METHODS: In vitro and in vivo preclinical studies were conducted. Patients (aged ≥18 years) received PF-06952229 monotherapy [20-500 mg, oral b.i.d., 7 days on/7 days off, 28-day cycles, Part 1A (P1A)] for advanced/metastatic solid tumors and combination therapy [250/375 mg with enzalutamide, Part 1B (P1B)] for metastatic castration-resistant prostate cancer (mCRPC). Primary endpoints were dose-limiting toxicity (DLT), adverse events (AEs), and laboratory abnormalities. Efficacy, pharmacokinetic parameters, and biomarker modulation were assessed. RESULTS: PF-06952229 showed activity in preclinical murine tumor models including pSMAD2 modulation in tumors. The study (NCT03685591) enrolled 49 patients (P1A, n = 42; P1B, n = 7). DLTs were reported in 3/35 (8.6%) P1A patients receiving PF-06952229 375 mg (anemia, intracranial tumor hemorrhage, and anemia and hypertension, all grade 3, n = 1 each). The most frequent grade 3 treatment-related AEs (TRAEs) were alanine aminotransferase increased and anemia (9.5% each). There were no grade 4-5 TRAEs. Plasma PF-06952229 exposures were dose proportional between 80 and 375 mg. Pharmacodynamic studies confirmed target modulation of pSMAD2/3 (peripheral monocytes). One P1A patient with prostate cancer receiving PF-06952229 375 mg monotherapy achieved confirmed partial response (31-month duration of response). A total of 8 patients (P1A, n = 6; P1B, n = 2) achieved stable disease. CONCLUSIONS: Antitumor activity of PF-06952229 was observed in preclinical studies. PF-06952229 was generally well tolerated with manageable toxicity; a small group of patients achieved durable responses and/or disease stabilization.
- Published
- 2024