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Gartrell BA, Roach M, Retter A, Sokol GH, Del Priore G, Scher HI. Phase II trial of SM-88, a cancer metabolism based therapy, in non-metastatic biochemical recurrent prostate cancer. Invest New Drugs 2020; 39:499-508. [PMID: 32924093 PMCID: PMC7960617 DOI: 10.1007/s10637-020-00993-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 08/21/2020] [Indexed: 11/27/2022]
Abstract
Background Androgen deprivation therapy (ADT) is a standard treatment for high-risk biochemically-recurrent, non-metastatic prostate cancer (BRPC) but is not curative and associated with toxicity. Racemetyrosine (SM-88) is an amino-acid analogue used with methoxsalen, phenytoin, and sirolimus (MPS) to enhance SM-88 activity. Method A phase 1b/2, open-label trial in BRPC and rising PSA. Patients were given daily SM-88 (230 mg BID), methoxsalen (10 mg), phenytoin (50 mg), and sirolimus (0.5 mg)). Outcome measures included changes in PSA, circulating tumor cells (CTCs) and imaging. Results 34 subjects were screened, 23 treated and 21 remained on study for ≥12 weeks. The median PSA was 6.4 ng/ml (range 1.7-80.1); doubling-time 6.2 months (range 1.4-36.6) and baseline testosterone 319.1 ng/ml (range 2.5-913.7). Median duration of therapy was 6.5 months (2.6-14.0). CTCs (median 48.5 cells/4 ml (range 15-268) at baseline) decreased a median of 65.3% in 18 of 19 patients. For patients who achieved an absolute CTC nadir count of <10 cells/4 ml (n = 10), disease control was 100% i.e. no metastases or PSA progression, while on trial (p = 0.005). PSA fell by ≥50% in 4.3% (1 subject). No patients developed metastatic disease while on treatment (metastases free survival =100%). There were no treatment-related adverse events (AEs) and quality of life was unchanged from baseline on the EORTC QLQ-C30 and QLQ-PR25. Testosterone levels rose slightly on SM-88 and were unrelated to efficacy or toxicity. Conclusions Use of SM-88 was associated with disease control while maintaining QOL. SM-88 may delay the need for ADT and the associated hormonal side effects. Larger trials are planned.Trial registration number, date of registration - NCT02796898, June 13, 2016.
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Affiliation(s)
- Benjamin A Gartrell
- Albert Einstein College of Medicine, Departments of Oncology and Urology, Montefiore Einstein Center for Cancer Care, Montefiore Medical Center, New York, NY, USA.
| | - Mack Roach
- Departments of Radiation Oncology & Urology, University of California San Francisco (UCSF) Helen Diller Family Comprehensive Cancer Center (HDFCC), San Francisco, CA, USA
| | - Avi Retter
- NY Cancer and Blood Specialist, East Setauket, NY, USA
| | - Gerald H Sokol
- Division of Clinical Pharmacology, Uniform Services University of the Health Sciences, Bethesda, MD, USA.,Florida Cancer Specialist and Research Institute, Fort Myers, FL, USA.,TYME Inc, New York, NY, USA
| | | | - Howard I Scher
- Genitourinary Oncology Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA.,Department of Medicine, Weill Cornell Medical College, New York, NY, USA
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