Phase II Trial of Enzalutamide and Androgen Deprivation Therapy with Salvage Radiation in Men with High-risk Prostate-specific Antigen Recurrent Prostate Cancer: The STREAM Trial

Rhonda L. Bitting, Patrick Healy, Daniel J. George, Monika Anand, Sung Kim, Tina Mayer, Carol Winters, Colleen Riggan, Julia Rasmussen, Rhonda Wilder, Mark Stein, Bart Frizzell, Michael R. Harrison, Tian Zhang, William R. Lee, Yuan Wu, Bridget F. Koontz, Andrew J. Armstrong

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

BACKGROUND: Salvage external beam radiotherapy (RT) with androgen deprivation therapy (ADT) improves survival over RT in men with prostate cancer (PC) and rising prostate-specific antigen (PSA) levels after radical prostatectomy (RP). OBJECTIVE: To investigate the safety and efficacy of enzalutamide concurrent with salvage RT and ADT. DESIGN, SETTING, AND PARTICIPANTS: This was a three-center prospective phase 2 single-arm trial (NCT02057939) of men with Gleason 7-10 PC and PSA recurrence within 4 yr of RP ranging from 0.2 to 4.0 ng/dl, no prior hormonal therapy, and no radiographic evidence of metastases. We enrolled 38 men; 37 completed therapy and were evaluable with testosterone recovery at 2 yr. INTERVENTION: Six months of ADT with 160 mg/d enzalutamide and 66 Gy RT to the prostate bed. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary endpoint was improved 2-yr progression-free survival (PFS) over historical controls. Secondary objectives included 3-yr PFS, safety, and patient-reported quality of life (QOL). RESULTS AND LIMITATIONS: The primary endpoint of 2-yr PFS was 65% (95% confidence interval [CI]: 47, 78) versus 51% (95% CI: 33, 67) in a trial of men with similar eligibility treated with salvage RT and adjuvant docetaxel. The 3-yr PFS was 53%. Eleven (29%) men experienced G3 toxicities, and there were no G4-5 or unexpected toxicities. QOL data suggest modest worsening of bowel, bladder, and hormonal symptoms at 3 mo, with recovery by 24 mo in most men. CONCLUSIONS: Salvage RT with enzalutamide and ADT following RP for men with PSA recurrent high-risk PC is safe and demonstrates encouraging efficacy, warranting prospective controlled phase 3 trials of ADT with or without potent androgen receptor inhibition in this curative-intent setting. PATIENT SUMMARY: Addition of 6 mo of oral daily enzalutamide to standard salvage radiation and hormone therapy is safe and may improve prostate cancer remission rates at 2 and 3 yr.

Original languageEnglish (US)
Pages (from-to)948-954
Number of pages7
JournalEuropean Urology Oncology
Volume4
Issue number6
DOIs
StatePublished - Dec 1 2021
Externally publishedYes

Keywords

  • Enzalutamide
  • Hormonal therapy
  • Prostate cancer
  • Salvage radiation

ASJC Scopus subject areas

  • Medicine(all)

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