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Primary, secondary, and quality-of-life endpoint results from PREVAIL, a phase 3 study of enzalutamide in men with metastatic castration resistant prostate cancer (mCRPC).
Abstracts that were granted an exception in accordance with ASCO's Conflict of Interest Policy are designated with a caret symbol (^).
Background: Enzalutamide (ENZ), an androgen receptor inhibitor, improved overall survival (OS) in men with mCRPC who had received prior docetaxel therapy (Scher, N Engl J Med 2012;367:13). The PREVAIL study examined whether ENZ could prolong OS and radiographic progression-free survival (rPFS) in men with mCRPC who had progressed on androgen deprivation therapy (ADT). Methods: In this randomized double-blind, placebo-controlled, multinational study (NCT01212991), asymptomatic or mildly symptomatic patients were randomized 1:1 to ENZ 160 mg/day or placebo (PBO). OS and rPFS were co-primary endpoints and analyzed for the intent-to-treat population. Key prespecified secondary and exploratory endpoints are noted in the table below. Results: 872 men were randomized to ENZ and 845 to PBO, with respective median treatment durations of 16.6 and 4.6 months. Based on a planned interim analysis at 540 deaths the Data Monitoring Committee recommended stopping the study and crossing PBO patients to ENZ. Efficacy results are shown in the Table. The most common adverse events with a higher incidence in the ENZ arm than PBO were fatigue (35.6% vs 25.8%), back pain (27.0% vs 22.2%), constipation (22.2% vs 17.2%), and arthralgia (20.3% vs 16.0%). Seizure was reported in 1 patient in each treatment arm (0.1%). Conclusions: In men with mCRPC who progress on ADT, treatment with enzalutamide has a favorable safety profile and significantly improves OS, rPFS, and secondary measures of disease response and progression. Clinical trial information: NCT01212991.
|Co-primary endpoints||Est. median (95% CI) months
||HR (95% CI)||P value|
|OS||32.4 (31.5, NYR)||30.2 (28, NYR)||0.71 (0.60, 0.84)||< 0.0001|
|rPFS||NYR (13.8, NYR)||3.9 (3.7, 5.4)||0.19 (0.15, 0.23)||< 0.0001|
|Other efficacy endpoints|
|Time to cytotoxic chemotherapy||0.35 (0.30, 0.40)||< 0.0001|
|Time to antineoplastic treatmenta||0.27 (0.24, 0.31)||< 0.0001|
|Time to first SRE||0.72 (0.61, 0.84)||< 0.0001|
|Time to PSA progression||0.17 (0.15, 0.20)||< 0.0001|
|Time to FACT-P degradation||0.63 (0.54, 0.72)||< 0.0001|
|Best objective response (CR+PR)||ENZ = 58.8%
PBO = 5.0%
|PSA decline from baseline||ENZ||PBO|
|≥ 50%||78.0%||3.5%||< 0.0001|
|≥ 90%||46.8%||1.2%||< 0.0001|
a Cytotoxic, hormonal, or investigational therapy.
Abstracts by Andrew J. Armstrong:
A Phase 3, randomized, double-blind, placebo-controlled study of tasquinimod (TASQ) in men with metastatic castration-resistant prostate cancer (mCRPC), secondary endpoints.Meeting: 2016 Genitourinary Cancers Symposium | Abstract No: 239
Analysis of the PROCEED registry by baseline prostate-specific antigen (PSA) quartiles: Preliminary analysis of real-world sipuleucel-T (sip-T) use.Meeting: 2016 Genitourinary Cancers Symposium | Abstract No: 193
Changing characteristics of patients treated with sipuleucel-T (sip-T) over time: Real-world experience from the PROCEED registry.Meeting: 2016 Genitourinary Cancers Symposium | Abstract No: 320