Safety and effectiveness of RBD-specific polyclonal equine F(ab')2 fragments for the treatment of hospitalized patients with severe Covid-19 disease: a retrospective cohort study. (preprint)

Passive immunotherapy has been evaluated as a therapeutic alternative for patients with COVID-19 disease. Equine polyclonal immunotherapy for COVID-19 (EPIC) showed adequate safety and potential efficacy in a clinical trial setting and obtained emergency use authorisation in Argentina. We studied its utility in a real world setting with a larger population. Methods: We conducted a retrospective cohort study at "Hospital de Campana Escuela-Hogar" in Corrientes, Argentina, to assess safety and effectiveness of EPIC in hospitalized adults with severe COVID-19 pneumonia. Primary endpoints were 28-days all cause mortality and safety. Mortality and improvement in modified WHO clinical scale at 14 and 21 days were secondary endpoints. Potential confounder adjustment was made by logistic regression weighted by the inverse of the probability of receiving the treatment (IPTW) and doubly robust approach. Results: Clinical records of 395 exposed (EPIC) and 446 non-exposed (Controls) patients admitted between November 2020 and April 2021 were analyzed. Median age was 58 years, 56.8% males. Mortality at 28 days was 15.7% ( EPIC) vs 21.5% (Control). After IPTW adjustment the OR was 0.66 (95 % CI: 0.46 - 0.96) p= 0.03. The effect was more evident in the subgroup who received two EPIC doses (complete treatment, n=379), OR 0.58 (95% CI 0.39 to 0.85) p=0.005. Overall and serious adverse events were not significantly different between groups.

RBD-Specific Polyclonal F(ab´) 2 Fragments of Equine Antibodies in Patients with Moderate to Severe COVID-19 Disease: A Randomized, Double-Blind, Placebo-Controlled, Adaptive Phase 2/3 Clinical Trial (preprint)

Background: Passive immunotherapy is a therapeutic alternative for patients with COVID-19. Equine polyclonal antibodies (EpAbs) could represent a source of easily scaled up neutralizing antibodies against SARS-CoV-2.Methods: We conducted a double-blind, randomized, placebo-controlled trial of EpAbs (INM005) in hospitalized adult patients with moderate and severe COVID-19 pneumonia in 19 hospitals of Argentina. Primary endpoint was improvement in at least two categories in WHO ordinal clinical scale at day 28 (ClinicalTrials.gov number NCT04494984).Findings: Enrolled patients were assigned to receive two doses of INM005 (n=118) or placebo (n=123). Median age was 54 years old, 65·1% were male and 61% had moderate disease at baseline. The median time from the onset of COVID-19 symptoms to the administration of the first dose of intervention was 6 days (interquartile range 5 to 8 days). At day 28 no significant difference was noted between study groups on primary endpoint (odds ratio, 1·61%, 95% confidence interval [95%CI] 0·71 to 3·63 p=0·34); however, overall variation in ordinal clinical status during the 28 days follow up period favored INM005. Improvement in at least two categories was significantly higher in INM005 at days 7, 14 and 21 of follow up. A significant difference was noted in time to improvement in at least two ordinal categories or hospital discharge: 14·2 (± 0·7) days in the INM005 group and 16·3 (± 0·7) days in the placebo group. Pre-specified subgroup analyses showed a more pronounced effect of the intervention over severe patients and with no antibody response at baseline. Overall mortality was 6·8% the INM005 group and 11·4% in the placebo group.Interpretation: Albeit not having reached the primary endpoint, we found clinical improvement of hospitalized patients with SARS-CoV-2 pneumonia, particularly those with severe disease. Funding: Funded by Inmunova and grants from the Ministries of Science and Production of Argentina.Trial Registration: ClinicalTrials.gov number NCT04494984Declaration of Interests: MC, SS, VZ, LM, LS, FG received grants from Ministerio de Desarrollo Productivo “Programa soluciona. reactivación de la economía del conocimiento” and Agencia Nacional de Promoción de la Investigación, el Desarrollo Tecnológico y la Innovación del Ministerio de Ciencia, Tecnología e Innovación. MD, JF, GV, AB, FC, MFA, LB, RT, SL, DS, MI, VS, RS, PC, MMC, LA, HLL, AC, DC declare reimbursement for conduction of clinical trial as investigator of the study. PC, OS, YK report other funds from Inmunova. EN, GL, WHB, SPLL report personal fees from Inmunova. AP, B de M, SM, Gabriel L declare no competing interests. SPLL declare personal fees from Movement Disorders Society, Laboratorio Elea and Merck pharmaceuticals.Ethics Approval Statement: The study protocol was approved by the Institutional Review Boards of all participant clinical sites as well as regional or jurisdictional Ethics Committees as applicable. The Argentinean National Administration of Medicines, Food and Medical Technology (ANMAT) also approved the study protocol.