Treatments for Metastatic Hormone-sensitive Prostate Cancer: Systematic Review, Network Meta-analysis, and Benefit-harm assessment

CONTEXT

Multiple treatments for metastatic, hormone-sensitive prostate cancer (mHSPC) are available, but their effects on health-related quality of life (HRQoL) and benefit-harm balance remain unclear.

OBJECTIVE

To assess clinical effectiveness regarding survival and HRQoL, safety, and benefit-harm balance of mHSPC treatments.

EVIDENCE ACQUISITION

We searched MEDLINE, EMBASE, CENTRAL, and ClinicalTrials.gov until March 1, 2022. Randomized controlled trials (RCTs) comparing docetaxel, abiraterone, enzalutamide, apalutamide, darolutamide, and radiotherapy combined with androgen deprivation therapy (ADT) mutually or with ADT alone were eligible. Three reviewers independently performed screening, data extraction, and risk of bias assessment in duplicate.

EVIDENCE SYNTHESIS

Across ten RCTs, we found relevant survival benefits for ADT + docetaxel (high certainty according to the Grading of Recommendations, Assessment, Development and Evaluation [GRADE]), ADT + abiraterone (moderate certainty), ADT + enzalutamide (low certainty), ADT + apalutamide (high certainty), and ADT + docetaxel + darolutamide (high certainty) compared with ADT alone. ADT + radiotherapy appeared effective only in low-volume de novo mHSPC. We found a short-term HRQoL decrease lasting 3-6 mo for ADT + docetaxel (moderate certainty) and a potential HRQoL benefit for ADT + abiraterone up to 24 mo of follow-up (moderate certainty) compared with ADT alone. There was no difference in HRQoL for ADT + enzalutamide, ADT + apalutamide, or ADT + radiotherapy over ADT alone (low-high certainty). Grade 3-5 adverse effect rates were increased with all systemic combination treatments. A benefit-harm assessment showed high probabilities (>60%) for a net clinical benefit with ADT + abiraterone, ADT + enzalutamide, and ADT + apalutamide, while ADT + docetaxel and ADT + docetaxel + darolutamide appeared unlikely (<40%) to be beneficial.

CONCLUSIONS

Despite substantial survival benefits, no systemic combination treatment showed a clear HRQoL improvement compared with ADT alone. We found evidence for a short-term HRQoL decline with ADT + docetaxel and a higher net clinical benefit with ADT + abiraterone, ADT + apalutamide and ADT + enzalutamide. While individualized decision-making remains important and economic factors need to be considered, the evidence may support a general preference for the combination of ADT with androgen receptor axis-targeted therapies over docetaxel-containing strategies.

PATIENT SUMMARY

We assessed different combination treatments for metastatic hormone-sensitive prostate cancer. While survival was better with all systemic combination treatments, there was no clear improvement in health-related quality of life compared with androgen deprivation therapy alone. Novel hormonal combination treatments had a more favorable benefit-harm balance than combination treatments that include chemotherapy.

Survival modelling and cost-effectiveness analysis of treatments for newly diagnosed metastatic hormone-sensitive prostate cancer

BACKGROUND

In metastatic hormone-sensitive prostate cancer (mHSPC) treatment, survival benefits have been shown by adding docetaxel or recent androgen receptor axis-targeted therapies (ARATs) abiraterone, apalutamide, or enzalutamide to androgen deprivation therapy (ADT). However, the optimal treatment strategy in terms of costs and effects is unclear, not least due to high ARAT costs.

METHODS

To assess treatment cost-effectiveness, we developed a Markov cohort model with health states of progression-free disease, progressive disease and death for men with newly diagnosed mHSPC, with a 30-year time horizon. Survival data, adverse events and utilities were informed by randomized controlled trial results, our meta-analysis of re-created individual patient survival data, and publicly available sources of unit costs. We applied a Swiss healthcare payer perspective and discounted costs and effects by 3%.

RESULTS

We found a significant overall survival benefit for ADT+abiraterone versus ADT+docetaxel. The corresponding incremental cost-effectiveness ratio (ICER) was predicted to be EUR 39,814 per quality-adjusted life-year (QALY) gained. ADT+apalutamide and ADT+enzalutamide incurred higher costs and lower QALYs compared to ADT+abiraterone. For all ARATs, drug costs constituted the most substantial cost component. Results were stable except for a large univariable reduction in the pre-progression utility under ADT+abiraterone and very large variations in drug prices.

CONCLUSIONS

Our model projected ADT+abiraterone to be cost-effective compared to ADT+docetaxel at a willingness-to-pay threshold of EUR 70,400/QALY (CHF 100,000 applying purchasing power parities). Given lower estimated QALYs for ADT+apalutamide and ADT+enzalutamide compared to ADT+abiraterone, the former only became cost-effective (the preferred) treatment option(s) at substantial 75-80% (80-90%) price reductions.