ASCO 2020: Cost-Effectiveness of Novel Antiandrogens for Treatment of Nonmetastatic Castrate-Resistant Prostate Cancer

(UroToday.com) The landscape of treatment options for patients with non-metastatic castration-resistant prostate cancer (nmCRPC) has changed rapidly since the spring of 2018. Up until the presentation of SPARTAN and PROSPER trials, reporting on the use of apalutamide and enzalutamide in non-metastatic castration-resistant prostate cancer, at GU ASCO in February 2018, there were no specifically approved treatment options for these patients. These agents, as well as darolutamide, were subsequently approved based on demonstrated improvements in metastasis-free survival. Since this time, further data have been presented demonstrating an overall survival benefit to these agents.

However, these novel androgen axis inhibiting agents are expensive and the utilization of these agents earlier in the disease process is associated with significantly longer durations of therapy. To explore this issue further, Irbaz Bin Riaz, MS, MBBS, and colleagues presented a cost-effectiveness analysis assessing three novel AAs (Apalutamide, Darolutamide, and Enzalutamide) in combination with androgen deprivation therapy (ADT) for treatment of patients with nmCRPC in a Poster session of the 2020 American Society of Clinical Oncology Virtual Annual Meeting.

The authors constructed a Markov state-transition model with a lifetime horizon. The authors considered three health states (Metastasis-Free Survival (MFS), Metastatic disease, and Death) in this model. A United States health care payer perspective was utilized.

To inform model estimates, the authors performed a network meta-analysis of MFS and overall survival due to the lack of head to head trials. Given the lack of reported individual-level patient data, the authors derived this information from digitized Kaplan-Meier curves for overall survival and MFS with Weibull distributions. 

cost effectiveness of novel anti androgens for treatment

Medication costs were based on wholesale acquisition cost. Adverse event (AE) grades 3/4 management costs were incorporated into the model. 

As is a standard modeling approach, the authors discounted both costs and effects 3% annually.

For each medication, the authors estimated life-years and quality-adjusted life years (QALYs) as well as the incremental cost-effectiveness ratio (ICER) and incremental cost-utility ratio (ICUR).

In the base-case analysis, each novel androgen axis inhibitor was associated with gains in life years and quality-adjusted life years, albeit at significant cost. 

BaseCaseAnalyses.png

Analyzing the incremental cost-effectiveness ratio, the authors demonstrated that many of these exceeded commonly accepted willingness-to-pay thresholds. Compared to ADT, apalutamide and ADT is most likely to be cost-effective based on the greatest QALY gains despite higher costs.

IncrementalCostEffectiveness.png


The authors found similar results in several probabilistic sensitivity analyses. As shown in the plot below, treatment with each of the novel androgen axis inhibitors is associated with QALY gains at the expense of greater cost.

Cost_QALY_gains.png


Presented by: Irbaz Bin Riaz, MBBS, MS, Mayo Clinic, Rochester, MN

Co-Authors: Abdulaali Almutairi, Daenielle K. Lang, Noureen Asghar, Anum Riaz, Yuan Yao, Qurat Ul Ain Riaz Sipra, Alexander J. Ryu, Nimer S Alkhatib, Mok Oh, Ivo Abraham, M. Hassan Murad, Manish Kohli

Written by: Christopher J.D. Wallis, Urologic Oncology Fellow, Vanderbilt University Medical Center, Twitter: @WallisCJD on Twitter at the 2020 American Society of Clinical Oncology Virtual Annual Meeting (#ASCO20), May 29th-May 31st, 2020

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