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Kemp Bohan PM, Chick RC, O'Shea AE, Vreeland TJ, Hickerson AT, Cindass JL, Ensley DC, Hale D, Clifton GT, Sohn VY, Thompson IM, Peoples GE, Liss MA. Phase I Trial of Encapsulated Rapamycin in Patients with Prostate Cancer Under Active Surveillance to Prevent Progression. Cancer Prev Res (Phila) 2021; 14:551-562. [PMID: 33514567 DOI: 10.1158/1940-6207.capr-20-0383] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 10/28/2020] [Accepted: 01/21/2021] [Indexed: 11/16/2022]
Abstract
No approved medical therapies prevent progression of low-grade prostate cancer. Rapamycin inhibits cell proliferation and augments immune responses, producing an antitumor effect. Encapsulated rapamycin (eRapa) incorporates rapamycin into a pH-sensitive polymer, ensuring consistent dosing. Here, we present results from a phase I trial evaluating the safety and tolerability of eRapa in patients with prostate cancer. Patients with Gleason ≤7 (3+4) disease (low and intermediate risk) under active surveillance were enrolled in a 3+3 study with three eRapa dosing cohorts (cohort 1, 0.5 mg/week; cohort 2, 1 mg/week; and cohort 3, 0.5 mg/day). Patients were treated for 3 months and followed for an additional 3 months to assess safety, pharmacokinetics, quality of life (QoL), immune response, and disease progression. Fourteen patients (cohort 1, n = 3; cohort 2, n = 3; and cohort 3, n = 8) were enrolled. In cohort 3, one dose-limiting toxicity (DLT; neutropenia) and two non-DLT grade 1-2 adverse events (AE) occurred that resulted in patient withdrawal. All AEs in cohorts 1 and 2 were grade 1. Peak serum rapamycin concentration was 7.1 ng/mL after a 1 mg dose. Stable trough levels (∼2 ng/mL) developed after 48-72 hours. Daily dosing mildly worsened QoL, although QoL recovered after treatment cessation in all categories, except fatigue. Weekly dosing increased naïve T-cell populations. Daily dosing increased central memory cell populations and exhaustion markers. No disease progression was observed. In conclusion, treatment with eRapa was safe and well-tolerated. Daily dosing produced higher frequencies of lower grade toxicities and transient worsening of QoL, while weekly dosing impacted immune response. Future studies will verify clinical benefit and long-term tolerability.Prevention Relevance: There is an unmet medical need for a well-tolerated treatment capable of delaying progression of newly diagnosed low-grade prostate cancer. This treatment would potentially obviate the need for future surgical intervention and improve the perception of active surveillance as a more acceptable option among this patient population.
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Affiliation(s)
| | - Robert C Chick
- Department of Surgery, Brooke Army Medical Center, Ft. Sam Houston, Texas
| | - Anne E O'Shea
- Department of Surgery, Brooke Army Medical Center, Ft. Sam Houston, Texas
| | - Timothy J Vreeland
- Department of Surgery, Brooke Army Medical Center, Ft. Sam Houston, Texas
| | | | - Jessica L Cindass
- Department of Surgery, Brooke Army Medical Center, Ft. Sam Houston, Texas
| | - Daniel C Ensley
- Department of Urology, Brooke Army Medical Center, Ft. Sam Houston, Texas
| | - Diane Hale
- Department of Surgery, Brooke Army Medical Center, Ft. Sam Houston, Texas
| | - Guy T Clifton
- Department of Surgery, Brooke Army Medical Center, Ft. Sam Houston, Texas
| | - Vance Y Sohn
- Department of Surgery, Madigan Army Medical Center, Joint Base Lewis-McChord, Washington
| | - Ian M Thompson
- Department of Urology, UT Health-San Antonio, San Antonio, Texas.,CHRISTUS Santa Rosa Medical Center, San Antonio, Texas
| | | | - Michael A Liss
- Department of Urology, UT Health-San Antonio, San Antonio, Texas
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