Proxalutamide Treatment for COVID-19 Female Outpatients

During the continuing SARS-CoV-2 (COVID-19) pandemic, several studies have reported a significant difference in the rate of severe cases between adult females and adult males (42% vs 58%).Among children under the age of 14, the rate of severe cases was reported to be extremely low. To explain this difference, several theories have been proposed including cigarette smoking and lifestyle habits. However, no theory fits both the gender difference in severe cases as well as reduced risk in pre-pubescent children. Our past research on male androgenetic alopecia (AGA) has led us to investigate an association between androgens and COVID-19 pathogenesis. In normal subjects, androgen expression demonstrates significant variation between men and women as well as between adults and pre-pubescent children.

SARS-CoV-2 primarily infects type II pneumocytes in the human lung. SARS-CoV-2 enters pneumocytes, by anchoring to the ACE2 cell surface receptor. Prior to receptor binding, viral spike proteins undergo proteolytic priming by the transmembrane protease, serine 2 (TMPRSS2). TMPRSS2 inhibition or knock down reduces ability of SARS-CoV-1 (a related virus to SARS-CoV-2) to infect cells in vitro. Additionally, TMPRSS2 also facilitates entry of influenza A and influenza B into primary human airway cells and type II pneumocytes.

The human TMPRSS2 gene has a 15 bp androgen response element and in humans, androgens are the only known transcription promoters for the TMPRSS2 gene. In a study of androgen-stimulated prostate cancer cells (LNCaP), TMPRSS2 mRNA expression increase was mediated by the androgen receptor. Further, the ACE2 receptor, also critical for SARS-CoV-2 viral infectivity, is affected by male sex hormones with higher activity found in males.

Androgenetic alopecia (AGA), often referred to as male pattern hair loss, is the most common form of hair loss among men. The development of androgenetic alopecia is androgen mediated and is dependent on genetic variants found in the androgen receptor gene located on the X chromosome; thus, it is hypothesized that men with AGA would be more prone to severe COVID-19 disease. The investigators conducted a preliminary observational study of hospitalized COVID-19 patients at two Spanish tertiary hospitals between March 23-April 6, 2020 to test this theory. In total, 41 Caucasian males admitted to the hospitals with a diagnosis of bilateral SARS-CoV-2 pneumonia were analyzed. The mean age of patients was 58 years (range 23-79). Among them, 29 (71%) were diagnosed with AGA (16 (39%) were classified as severe AGA (Hamilton IV or above)) and 12 (29%) did not present clinical signs of AGA. The diagnosis of AGA was performed clinically by a dermatologist. The precise prevalence of AGA among otherwise healthy Spanish Caucasian males is unknown; however, based on published literature, the expected prevalence of a similar age-matched Caucasian population is approximately 31-53%.

Based on the scientific rationale combined with this preliminary observation, the investigators propose to test an anti-androgen as a treatment for patients recently diagnosed with COVID-19.

We have chosen the use of the novel second generation androgen receptor (AR) antagonist proxalutamide as a means for rapid reduction in AR activity. Proxalutamide (GT0918) demonstrates a dual mechanism of action. It is highly effective in inhibiting AR as well as exhibiting pharmacological effects of inducing the down-regulation of AR expression; the mechanism that is not present in bicalutamide and enzalutamide. Additionally, it has been reported that Proxalutamide lowers the expression of ACE2. Both would be beneficial for preventing SARS-CoV-2 entry into lung cells.

This study is intended to explore the possible protective role of anti-androgens in SARS-CoV-2 infection. Provided anti-androgens are effective in reducing the rate of COVID-19 hospitalization, subjects enrolled in this study may experience a lower rate of hospitalization.