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IntroductionAntiandrogens are candidates against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) due to host cell entry inhibition by the suppression of TMPRSS2. Proxalutamide is a nonsteroidal anti-androgen (NSAA) with strong antagonism on androgen receptor (AR) and angiotensin-converting enzyme 2 (ACE2). Efficacy of proxalutamide was previously demonstrated for early COVID-19 outpatients, and also reduction of deaths in hospitalized COVID-19 patients. Whether radiological changes would follow the improvement in clinical outcomes with proxalutamide is not established. The present post-hoc analysis aims to evaluate whether proxalutamide improves lung injury observed through chest computerized tomography (CT) scans. MethodsThis is a post-hoc analysis of the radiological findings of The Proxa-Rescue AndroCoV Trial with all enrolled patients from the three participating institutions of the city of Manaus, Brazil, that had at least two chest CT scans during hospitalization. The quantification of lung parenchyma involvement was performed by blinded radiologists with expertise in analysis of COVID-19 images. A first chest CT scan was performed upon randomization and a second CT scan was performed approximately five days later, whenever feasible. Improvement rate was the first endpoint, and relative and absolute changes between the first and second CT scans were the second endpoints. ResultsOf the 395 patients initially evaluated, 77 and 169 patients from the proxalutamide and placebo arms, respectively, were included (n=246). Baseline characteristics and percentage of lung parenchyma affected in the baseline chest CT scan were similar between groups. In the second chest CT scan, the percentage of lungs affected (Median - IQR) was 35.0% (25.0-57.5%) in the proxalutamide group versus 67.5% (50.0-80.0%) in the placebo group (p < 0.001). The absolute and relative change between the second and first chest CT scans (Median - IQR) were -15.0 percent points (p.p.) (-30.0 - 0.0p.p.) and -25.0% (-50.0 - 0.0%) in the proxalutamide group, respectively, and +15.0p.p. (0.0 - +30.0p.p.) and +32.7% (0.0 - +80.0%) in the placebo group, respectively (p < 0.001 for both absolute and relative changes). The improvement rate, i.e., the percentage of subjects that had improvement from the first to the second CT scan, was 72.3% in the proxalutamide group and 23.1% in the placebo group (p < 0.0001), with an improvement rate ratio (95%CI) of 3.15 (2.32 - 4.28). ConclusionProxalutamide improves lung opacities in hospitalized COVID-19 patients when compared to placebo. (NCT04728802)
RESUMEN
IntroductionProxalutamide, 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. We observed a high 28-day mortality rate of patients that did not complete the 14-day treatment with proxalutamide, compared to the placebo arm. These differences may raise hypotheses to explain the wide differences between ITT and on-treatment (OT) analysis in terms of 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. MethodsThis 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. OT population excluded patients that did not complete the full 14-day course of therapy or died from COVID-19 complications within 24 hours of randomization. The primary outcome was the 28-day COVID-19 mortality rate. Secondary outcomes included median hospital length, 14-day and 28-day alive hospital discharge rate and 28-day all-cause mortality rate of those who discontinued intervention. ResultsIn 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 COVID-19 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 5 days (interquartile range [IQR] = 3 to 7.2 days) in the proxalutamide group and 9 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). ConclusionThe reduction in 28-day all-cause mortality rate with 14-day proxalutamide treatment for hospitalized COVID-19 patients was more significant while on treatment adhesion (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)