Proxalutamide (GT0918) Reduction of Mortality Rate in Hospitalized COVID-19 Patients Depends on Treatment Duration - an Exploratory Analysis of the Proxa-Rescue AndroCoV Trial | medRxiv

Ricardo A Zimerman , Daniel N Fonseca , Michael N Correia , Renan N Barros , Dirce C Onety , Karla Cristina P Israel , Emilyn O Guerreiro , Jose Enrique M Medeiros , Raquel N Nicolau , Luiza Fernanda M Nicolau , Patricia S da Silva , Rafael X Cunha , Maria Fernanda R Barroco , Raysa WS Paulain , Claudia E Thompson , Andy Goren , View ORCID Profile Flavio A Cadegiani

doi: https://doi.org/10.1101/2021.06.28.21259661

Abstract

Introduction: Proxalutamide, a second generation non-steroidal antiandrogen (NSAA), primarily developed for castration-resistant prostate cancer, demonstrated reduction in 28-day mortality rate of 77.7% in hospitalized COVID-19 patients in a double-blind, placebo-controlled, two-arm randomized clinical trial (RCT), through intention-to-treat (ITT) analysis. However, the intriguingly high 28-day mortality rate of patients that did not complete the 14-day treatment with proxalutamide, compared non-completers of the placebo arm and overall placebo arm, raised the hypotheses of the existence of non-neglectable differences between ITT and on-treatment (OT) analysis in terms of drug efficacy. Despite the inherent limitations of OT analysis, we aimed to respond to unanswered questions regarding the drug efficacy when the 14-day treatment with proxalutamide was complete, and secondarily understand the causality relationship between treatment interruption and mortality rate. Methods: This is a post-hoc exploratory analysis of a double-blinded, randomized, placebo-controlled, prospective, multicentric, two-arm RCT of 300mg-daily 14-day proxalutamide therapy for hospitalized COVID-19 patients not requiring mechanical ventilation, using OT population, i.e., excluding patients that did not complete treatment or interrupted at least 24 hours before death. Patients above 18 years old with confirmed COVID-19 not presenting kidney, liver, or heart failure were eligible. The primary outcome was 8-point COVD-19 ordinal scale at day 14. Secondary outcomes included 28-day 8-point COVID-19 ordinary scale, 14-day and 28-day all-cause mortality rate, and median hospital length. Results: In total, 580 patients completed the 14-day treatment or died during treatment, including 288 patients in the proxalutamide arm and 292 patients in the placebo arm, with similar baseline characteristics between groups. The 28-day all-cause mortality rate was 4.2% in the proxalutamide group and 49.0% in the placebo group. The mortality risk ratio (RR) was 0.08 (95% CI, 0.05-0.15), with a number needed to treat (NNT) of 2.2 to prevent death. The median hospital length stay after randomization was 05 days (interquartile range - IQR = 3 to 7.2 days) in the proxalutamide group and 09 days (IQR = 6 to 15 days) in the placebo group (p < 0.001). The 28-day all-cause mortality rate of patients that received proxalutamide but interrupted treatment before 14 days was 79.3%, while those that received placebo and interrupted before 14 days was 52.8% (p = 0.054 between groups). Conclusion: The reduction in 28-day all-cause mortality rate with 14-day proxalutamide treatment for hospitalized COVID-19 patients was more significant treatment completers (92%), compared to the reduction when all patients enrolled in the proxalutamide arm were considered (77.7%). However, the magnitude of statistical significance of the reduction in all-cause mortality and the NNT were similar between the OT and ITT analysis. The apparent high mortality risk rate with early interruption of proxalutamide treatments suggests that strategies for treatment compliance should be reinforced for future RCTs with proxalutamide. (NCT04728802)

Competing Interest Statement

Kintor Pharmaceuticals, Ltd. manufactures and plans to market proxalutamide, and has an investigational new drug (IND) application under United States Food and Drugs Administration to conduct a Phase 3 study for proxalutamide for COVID-19. Applied Biology, Inc. has patents pending regarding antiandrogen therapy for COVID-19. Dr. Goren, Dr. McCoy, and Dr. Li are employees of Applied Biology, Inc. Dr. Cadegiani has served as a clinical director for Applied Biology, Inc. Dr. Wambier has served as an advisor to Applied Biology, Inc. The other authors have no conflict of interest to declare.

Clinical Trial

NCT04728802

Funding Statement

Kintor Pharmaceuticals, Ltd. manufactures and plans to market proxalutamide, and has an investigational new drug (IND) application under United States Food and Drugs Administration to conduct a Phase 3 study for proxalutamide for COVID-19. Applied Biology, Inc. has patents pending regarding antiandrogen therapy for COVID-19. Dr. Goren, Dr. McCoy, and Dr. Li are employees of Applied Biology, Inc. Dr. Cadegiani has served as a clinical director for Applied Biology, Inc. Dr. Wambier has served as an advisor to Applied Biology, Inc. The other authors have no conflict of interest to declare.

Author Declarations

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The study was approved by an ethics committee and registered in clinicaltrials.gov (NCT04728802), and also approved by Brazilian National Ethics Committee, approval number 4.513.425; CAAE 41909121.0.0000.5553; Comite de Etica em Pesquisa (CEP) of the Comite Nacional de Etica em Pesquisa (CONEP) of the Ministry of Health (MS). (CEP/CONEP/MS).

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Yes

Data Availability

Data is available in case request is approved by the research team.

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https://www.medrxiv.org/content/10.1101/2021.06.28.21259661v1