Chloroquine diphosphate in two different dosages as adjunctive therapy of hospitalized patients with severe respiratory syndrome in the context of coronavirus (SARS-CoV-2) infection: Preliminary safety results of a randomized, double-blinded, phase IIb clinical trial (CloroCovid-19 Study)

Mayla Borba; Fernando de Almeida Val; Vanderson Sousa Sampaio; Marcia Araujo Alexandre; Gisely Cardoso Melo; Marcelo Brito; Maria Mourao; Jose Diego Brito Sousa; djane Baia-da-Silva; Marcus Vinitius Farias Guerra; Ludhmila Hajjar; Rosemary Costa Pinto; Antonio Balieiro; Felipe Gomes Naveca; Mariana Xavier; Alexandre Salomao; Andre Siqueira; Alexandre Schwarzbolt; Julio Henrique Rosa Croda; Mauricio Lacerda Nogueira; Gustavo Romero; Quique Bassat; Cor Jesus Fontes; Bernardino Albuquerque; Claudio Daniel-Ribeiro; Wuelton Monteiro; Marcus Lacerda

In a larger patient population, we found that a higher dosage of CQ for 10 days presented toxicity red flags, particularly affecting QTc prolongation. The limited sample size recruited so far does not allow to show any benefit regarding treatment efficacy, however the higher fatality associated with the higher dosage by day 13 of follow-up resulted in a premature halting of this arm. This is the first double-blinded, randomized clinical trial addressing different dosages of CQ for the treatment of severe patients with COVID-19 in the absence of a control group using placebo. Due to the impossibility of not using the drug recommended at the national level, we used historical data from the literature to infer comparisons for lethality endpoints. Follow-up until day 28 is ongoing with a larger sample size, in which long-term lethality will be better estimated.