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.

The economic burden of common adverse events associated with metastatic colorectal cancer treatment in the United States

AIMS

Adverse events (AEs) associated with treatments for metastatic colorectal cancer (mCRC) may compromise the course of treatment, impact quality-of-life, and increase healthcare resource utilization. This study assessed the direct healthcare costs of common AEs among mCRC patients in the US.

METHODS

Adult mCRC patients treated with chemotherapy or targeted therapies were identified from administrative claims databases (2009-2014). Up to the first three mCRC treatment episodes per patient were considered and categorized as with or without the AE system/organ category during the episode. Total healthcare costs (2014 USD) were measured by treatment episode and reported on a monthly basis. Treatment episodes with the AE category were matched by treatment type and line of treatment to those without the AE category. Adjusted total cost differences were estimated by comparing costs during treatment episodes with vs without the AE category using multivariate regression models; p-values were estimated with bootstrap.

RESULTS

A total of 4158 patients with ≥1 mCRC treatment episode were included (mean age = 59 years; 58% male; 60% with liver and 14% with lung metastases; 2,261 [54%] with a second and 1,115 [27%] with a third episode). On average, two treatment episodes were observed per patient with an average length of 166 days per episode. Adjusted monthly total cost difference by AE category included hematologic ($1,480), respiratory ($1,253), endocrine/metabolic ($1,213), central nervous system (CNS; $1,136), and cardiovascular ($1,036; all p < .05).

LIMITATIONS

Claims do not include information on the cause of AEs, and potentially less severe AEs may not have been reported by the physician when billing the medical service. This study aimed to assess the association between costs and AEs and not the causation of AEs by treatment.

CONCLUSIONS

The most costly AEs among mCRC patients were hematologic, followed by respiratory, endocrine/metabolic, CNS, and cardiovascular.