Effectiveness and Safety of Medical Treatment for SARS-CoV-2 (COVID-19) in Colombia

Initially, the use of the drugs chloroquine, hydroxychloroquine and lopinavir / ritonavir had been proposed in this study, based on laboratory results of their in vitro antiviral potency for the CoV-2 virus, but with limited clinical evidence. However, later there were problems with the safety of the use of azithromycin in patients with SARS Covid 19. The coordinating committee of this study decided by consensus to suspend the use of hydroxychloroquine in the clinical trial in question by means of minutes of June 9, 2020 given that the interim analysis of the Recovery study showed (on June 5) that "there are no differences between hydroxychloroquine and standard treatment (28-day mortality between HCQ hydroxychloroquine and standard treatment (28-day mortality outcome (25.7% hydroxychloroquine vs. 23.5% usual care; Hazard ratio (HR: 1.11 \[95% CI 0.98-1.26\]). "(21) On the other hand, on June 29, the same Recovery study published the results of the interim analysis on the use of lopinavir ritonavir in patients with SARS Covid 19. In a statement it reports that "there were no significant differences in the 28-day mortality outcome (22.1% of lopinavir-ritonavir versus 21.3 % of usual care; (relative risk RR 1.04 95% CI 0.91-1.18\]; no beneficial effects were found on the risk of progression to mechanical ventilation or the length of hospital stay "(22)

Given these results, it is relevant to know the clinical effectiveness and adverse effects of the drugs: emtricitabine / tenofovir, colchicine / rosuvastatin, compared with the usual management, as alternatives for the management of COVID-19 infection in real patient scenarios for support decision making in clinical practice.

Interim analysis and sample size

A sample size was calculated from a sensitivity analysis with three scenarios:

scenario 1 a total of 1,163 patients, that is, 291 per treatment arm with alpha of Alpha = 0.05; power 0.8; Prop1 = 0.2 and Prop2 = 0.1 (expected difference of 10%) and 10% of possible losses, scenario 2. With the previous parameters and with a Prop1 = 0.15 and Prop2 = 0.05 for a total of 814 patients (204 per arm of treatment) scenario 3. With Alpha = 0.1, Prop1 = 0.15 and Prop2 = 0.05, the other previous parameters, for a total of 686 patients (172 per treatment).

A sample size was calculated from a sensitivity analysis with three scenarios:

scenario 1 a total of 1,163 patients, that is, 291 per treatment arm with alpha of Alpha = 0.05; power 0.8; Prop1 = 0.2 and Prop2 = 0.1 (expected difference of 10%) and 10% of possible losses, scenario 2. With the previous parameters and with a Prop1 = 0.15 and Prop2 = 0.05 for a total of 814 patients (204 per arm of treatment) scenario 3. With Alpha = 0.1, Prop1 = 0.15 and Prop2 = 0.05, the other previous parameters, for a total of 686 patients (172 per treatment)

Under this new approach we will make an evaluation of the minimum effectiveness in scenarios 1 and 2 :

Stage 1 When completing the sample size of this stage (400 participants), a interim analysis will be carried out that allows testing whether there is an expected difference of 15 percent (25 percent - 10 percent), with a power of 84 percent. As in the previous analysis, if significant differences are found, the treatment with less effectiveness (highest mortality) is replaced. The correction of the type I error will be made using the O'Brien-Fleming method.

Stage 2. Estimation of effectiveness:

When we have a sample size of 290 participants in each intervention, allowing the evaluation of an expected difference of 10 (20percent - 10 percent) with a power of 81 percent and a significance level of 0.05. A loss percentage of 10 will be considered.

Rules for selecting a drug to be included in the RCT in stage 1

Criteria for inclusion of a new drug, in its order:

1. Evidence that the drug is safe in humans 2. The drug must have a record from the National Institute for Food and Drug Surveillance (Invima) 3. Drug's availability in the country 4. The drug must show at least 15 percent superiority to standard management in other randomized clinical trials that have been conducted in patients with SARS CoV-2 / COVID-19 5. Biological plausibility and studies that support the choice: in vitro case series studies, use in similar situations 6. Ongoing studies that are evaluating the drug's effectiveness and safety 7. The drug must meet the objective of the study

In the scenario 2 and 3 we will no do an interim analysis