Cost per median overall survival month associated with abiraterone acetate and enzalutamide for treatment of patients with metastatic castration-resistant prostate cancer

Objective: To calculate costs per median overall survival (OS) month in chemotherapy-naïve patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone acetate plus prednisone (AA?+?P) or enzalutamide. Methods: Median treatment duration and median OS data from published Phase 3 clinical trials and prescribing information were used to calculate costs per median OS month based on wholesale acquisition costs (WACs) for patients with mCRPC treated with AA?+?P or enzalutamide. Sensitivity analyses were performed to understand how variations in treatment duration and treatment-related monitoring recommendations influenced cost per median OS month. Cost-effectiveness estimates of other Phase 3 trial outcomes were also explored: cost per month of chemotherapy avoided and per median radiographic progression-free survival (rPFS) month. Results: The results demonstrated that AA?+?P has a lower cost per median OS month than enzalutamide ($3231 vs 4512; 28% reduction), based on the following assumptions: median treatment duration of 14 months for AA?+?P and 18 months for enzalutamide, median OS of 34.7 months for AA?+?P and 35.3 months for enzalutamide, and WAC per 30-day supply of $8007.17 for AA?+?P vs $8847.98 for enzalutamide. Sensitivity analyses showed that accounting for recommended treatment-related monitoring costs or assuming identical treatment durations for AA?+?P and enzalutamide (18 months) resulted in costs per median OS month 8–27% lower for AA?+?P than for enzalutamide. Costs per month of chemotherapy avoided were $4448 for AA?+?P and $5688 for enzalutamide, while costs per month to achieve median rPFS were $6794 for AA?+?P and $7963 for enzalutamide. Conclusions: This cost-effectiveness analysis demonstrated that costs per median OS month, along with costs of other Phase 3 trial outcomes, were lower for AA?+?P than for enzalutamide. The findings were robust to sensitivity analyses. These results have important implications for population health decision-makers evaluating the relative value of therapies for mCRPC patients.     

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.     

Number needed to treat and associated incremental costs of treatment with enzalutamide versus abiraterone acetate plus prednisone in chemotherapy-naïve patients with metastatic castration-resistant prostate cancer

Objective: Enzalutamide (ENZA) and abiraterone acetate plus prednisone (AA) are approved second-generation hormone therapies for chemotherapy-naïve metastatic castration-resistant prostate cancer (mCRPC). This study compared ENZA with AA in chemotherapy-naïve mCRPC by calculating the number needed to treat (NNT) and associated incremental costs to achieve one additional chemotherapy-naïve patient with mCRPC free of radiographic progression, chemotherapy, or death over a 1-year time horizon.

Methods: Clinical outcomes were obtained from the PREVAIL and COU-AA-302 trials. Three outcomes were evaluated: radiographic progression-free survival, time to cytotoxic chemotherapy initiation, and overall survival at 1 year. NNT was calculated as the reciprocal of the outcome event rate difference for ENZA compared with AA. The incremental costs to achieve one additional outcome at 1 year were calculated as the difference in cost per treated patient multiplied by the NNT. Per-treated-patient costs were considered from a US payer perspective and included medications, monitoring, adverse events, post-progression treatments, and end-of-life care.

Results: Within a 1-year time horizon, the total cost per treated patient for ENZA was $2,666 less than AA. Compared with AA, treating 14 patients with ENZA resulted in one additional patient free of progression or death over 1 year; treating 26 patients with ENZA resulted in one additional patient with chemotherapy delayed over 1 year; and treating 91 patients with ENZA resulted in one additional patient free of death over 1 year. Therefore, ENZA is cost-effective compared with AA for all three outcomes evaluated, and the modeled results suggest ENZA is associated with potentially improved clinical outcomes in delaying chemotherapy initiation and disease progression for chemotherapy-naïve patients. The results are robust in sensitivity analyses, where the effect of changes in key model inputs and assumptions were tested.

Conclusion: The results modeled in the present study suggest ENZA is cost-effective compared with AA for treating chemotherapy-naïve patients with mCRPC.