PDE4A and COVID-19: In light of the above, effects of PDE4 inhibitor apremilast in COVID-19 patients have been evaluated in the ongoing clinical trial named I-SPY_COVID (NCT04488081) where apremilast (30 mg orally, given twice a day for 14 days) has been combined with remdesivir (200 mg loading dose on day 1, followed by 100 mg given intravenously once daily for 4 or 9 days).