Cost-effectiveness model of abiraterone plus prednisone,cabazitaxel plus prednisone and enzalutamide for visceral metastatic castration resistant prostate cancer therapy after docetaxel therapy resistance

Abstract

Aims: Among patients diagnosed with prostate cancer, 10–20% will develop castration-resistant prostate cancer (CRPC) within 5?years; for 70%, CRPC will metastasize, mostly to the lungs and/or liver. We performed a cost-effectiveness model comparing abiraterone plus prednisone (ABI?+?PRD), cabazitaxel plus prednisone (CAB?+?PRD) and enzalutamide (ENZ) for visceral metastatic CRPC post-docetaxel therapy resistance.

Methods: A three-state (Progression-Free, Progression, Death) lifetime Markov model was constructed to compare ABI?+?PRD, CAB?+?PRD, and ENZ from a United States healthcare payer perspective (2019?US$; discount rate 3%/yr.). Effectiveness was measured in life-years (LYs) and quality-adjusted life years (QALYs). Inputs included treatment costs, grade III/IV adverse events with incidence ≥5%, physician follow-up, lab and imaging tests. Phase III trial Kaplan-Meier curves were extrapolated to estimate overall survival and Progression-Free transition probabilities. Incremental cost-effectiveness ratios (ICERs) and utility ratios (ICURs), probabilistic sensitivity analyses (PSAs) and cost-effectiveness acceptability curves at willingness-to-pay (WTP) thresholds were estimated.

Results: Models estimated 3-year overall survival rates of 1.3% for patients treated with ABI?+?PRD, 16.2% for CAB?+?PRD, and 13.2% for ENZ. Estimated Progression-Free rates at 1.5?years were 0.51% for ABI?+?PRD, 0.27% for CAB?+?PRD, and 14.47% for ENZ. LYs and QALYs were 1.20 and 0.58 respectively for ABI?+?PRD, 1.48 and 0.56 for CAB?+?PRD, and 1.58 and 0.79 for ENZ. Total treatment costs were: $115,433 for ABI?+?PRD, $85,337 for CAB?+?PRD and $109,213 for ENZ. CAB?+?PRD and ENZ dominated ABI?+?PRD due to higher LYs gained. Incremental QALYs for ENZ vs. CAB?+?PRD were larger than incremental LYs. The ICUR for ENZ was $103,674/QALY compared to CAB?+?PRD.

Conclusions: This analysis found ENZ provided greater LYs and QALYs than both ABI?+?PRD and CAB?+?PRD, at a lower cost than ABI?+?PRD, but at a higher cost compared to CAB?+?PRD. For patients with visceral mCRPC after docetaxel therapy resistance, ENZ was cost-effective 92% of the time with a WTP threshold of $100,000/QALY.     

Real-world incidence and burden of adverse events among non-metastatic prostate cancer patients treated with secondary hormonal therapies following androgen deprivation therapy

Abstract

Aims: To describe the incidence and identify prognostic factors of central nervous system (CNS) adverse events (AEs) and any AEs (CNS, skin rash, or fracture) and evaluate the healthcare resource utilization (HCRU), direct medical costs, and therapy discontinuation associated with these AEs among non-metastatic prostate cancer (nmPC) patients who received secondary hormone therapies.

Methods and results: nmPC patients who had initiated secondary hormonal therapy with enzalutamide, bicalutamide, or abiraterone ≥1?year after androgen deprivation therapy (ADT) were identified in the MarketScan database. Survival analyses were used to describe the incidence of CNS or any AEs. Annual HCRU and costs were compared across patient groups (CNS AE vs no CNS AE; any AE vs no AE) using propensity score weighted generalized linear models. Multivariate Cox proportional hazards models were used to identify AE predictors and compare risks of discontinuation.

Results: The analysis included 532 patients who initiated secondary hormonal therapies, among whom 201 (38%) and 244 (46%) experienced a CNS AE and any AE, respectively. Median times to CNS AE and any AE from therapy initiation were 17.90 and 11.00?months, respectively. Predictors of any AE were any AE in the baseline period (≤6?months before starting therapy), Charlson Comorbidity Index (CCI) score (1 vs 0), surgical castration, and older age. Predictors of CNS AEs were CNS AE in the baseline period and CCI score (1 vs 0). CNS and any AEs were associated with significantly higher HCRU. CNS AEs were associated with significantly higher incremental total medical costs ($18,522). CNS AEs and any AEs significantly increased therapy discontinuation risk by 48% and 38%, respectively.

Conclusions: AEs increase the economic burden and therapy discontinuation among nmPC patients receiving secondary hormonal therapies subsequent to ADTs. These patients should be carefully evaluated for AEs to reduce therapy discontinuation, HCRU, and direct medical costs.