Daily Regimen of Tenofovir/Emtricitabine as Prevention for COVID-19 in Health Care Personnel in Colombia

Background and Rationale The global impact of SARS-CoV-2/COVID-19 is unprecedented, and it is the greatest pandemic of a respiratory virus since the 1918 Influenza. With high infectiousness, important morbidity, and relatively high fatality in specific groups of the population, an attack rate of approximately 80%, and no vaccine available yet, the pandemic will exceed the capacity of the health care systems in many settings(1). The health care personnel represent the most valuable resource to respond to the challenges imposed by this pandemic. As health care professionals are in the frontline of response and at a high risk of infection, it is extremely important to establish effective prevention strategies that protect them from becoming infected (2). It is critical that these interventions be rigorously evaluated with designs such as RCT that provide the highest level of evidence, to make recommendations that effectively protect health care professionals and contribute to control the epidemic.

Both hand hygiene and the use of Personal Protective Equipment (PPE) are considered key strategies for the prevention of infection in health care professionals (3). However, there are few studies estimating the probability of infection with their use. Moreover, several pharmacological agents have been considered for a prophylactic use in SARS-CoV-2 infection.

As of today, there is preclinical evidence, principally in vitro, indicating antiviral effect of Tenofovir Disoproxil Fumarate / Emtiricitabine (TDF/FTC) on the SARS-CoV-2 RNA depended RNA polymerase. TDF/FTC is an approved drug for HIV treatment in combination with other antiretroviral drugs. It is widely used as HIV pre and post exposure prophylaxis, and it is the election therapy for Hepatitis B infection (4-7).

Knowing that TDF/FTC is a drug with a known security profile, has low frequency of short-term adverse events, and is capable of inhibiting SARS-CoV-2 replication in vitro, it is an interesting alternative to evaluate as prophylaxis for SARS-CoV-2 infection. Furthermore, recently, in a clinical cohort of 77590 persons living with HIV, it was documented that those receiving TDF/FTC had a risk of COVID 19 and related hospitalization between 37 a 57% lower than those who were taking other antiretroviral medications (8) Consequently, we consider relevant and justified to evaluate the use of TDF/FTC for the prevention of SARS-CoV-2 infection in a high-risk population, such as health care professionals providing clinical care to confirmed or suspected cases of COVID-19.

Tenofovir/Emtricitabine as prophylaxis for SARS-CoV-2 Infection SARS-CoV-2 is a single strand positive-sense RNA virus similar to Hepatitis C Virus, West Nile Virus, Marburg, HIV, Ebola, Dengue virus, and Rhinovirus among others. The RNA-dependent RNA polymerase (RdRp) is one of the structural proteins of SARS-CoV-2(9). The active site of RdRp is configured by two successive aspartate residues which protrude from a beta turn structure, making accessible to the surface through the nucleotide canal (10). The homology between SARS-CoV-2 RdRp and SARS-CoV-1 is higher than 97%, thus facilitating in silico studies (11).

In silico studies have identified antiretroviral drugs with potential capability of binding the catalytic center of RdRp such as Nucleoside Reverse Transcriptase Inhibitors. This information has been confirmed in vitro studies for TDF, which acts as analogue of a nucleotide that early finishes the replication of the RNA strand (12) Elfiky et al. made an RdRp SARS-CoV-2 model based on different available structures in protein banks. Using it and through simulation, they documented the theoretical effectiveness of several antiviral agents such as IDX-184, Sofosbuvir, Ribavirina y Remdisivir,and TDF/FTC for the inhibition of RdRp (10,13).

Furthermore, Park, et al. developed an animal model of SARS-CoV-2 in ferrets in which the pathogenicity, transmissibility, and lung damage caused by the virus were demonstrated. In an experiment using this model, the virus was inoculated by the intranasal route, and a day after, numerous molecules with potential antiviral effect were administrated. These molecules were: Lopinavir/Ritonavir, Hydroxychloroquine, TDF/FTC. The duration of the intervention was 14 days and the ferret group given TDF/FTC presented lower temperature compared to the control group, and also an earlier recovery from signs including cough, rhinorrhea, and reduction of activity. Moreover, a lower load of virus was detected in the nasal samples from ferrets in the intervention group. From the drugs studied TDF/FTC showed the best results in reducing clinical signs and clearing nasal viral shedding (9).

Furthermore, recently, in a clinical cohort of 77590 persons living with HIV, it was documented that those receiving TDF/FTC had a risk of COVID 19 and related hospitalization between 37 a 57% lower than those who were taking other antiretroviral medications (8)

Research question What are the effectiveness and safety of Tenofovir/ Emtricitabine in addition to the use of Personal Protective Equipment (PPE) for the prevention of SARS-CoV-2 infection in health care personnel who provide clinical care to confirmed or suspected cases of COVID-19 in the emergency room, COVID wards and ICU? General Objective To evaluate the effectiveness and safety of Tenofovir/ Emtricitabine in addition to the use of Personal Protective Equipment (PPE) for the prevention of SARS-CoV-2 infection in health care personnel who provide clinical care to confirmed or suspected cases of COVID-19 in the emergency room, COVID wards and ICU.

Specific Objectives

• To determine the effectiveness of Tenofovir Emtricitabine in addition to the use of Personal Protective Equipment (PPE) for the prevention of SARS-CoV-2 infection in health care personnel caring for patients with confirmed or suspected COVID-19 in the emergency room, general ward and ICU.
• To evaluate the safety (adverse events frequency) of Tenofovir Emtricitabine in addition to the use of Personal Protective Equipment (PPE) for the prevention of SARS-CoV-2 infection in health care personnel caring for patients with confirmed or suspected COVID-19 in the emergency room, general ward and ICU.
• To evaluate the adherence to Tenofovir Emtricitabine of health care personnel caring for patients with confirmed or suspected COVID-19in the emergency room, general ward and ICU.
• To determine the frequency of discontinuation for any reason of Tenofovir Emtricitabine in health care personnel caring for patients with confirmed or suspected COVID-19 in the emergency room, general ward, and ICU.
• To describe and compare the clinical course and severity of participants who develop COVID-19 in the intervention and control groups.

Study design

Randomized triple-blinded multicentric clinical trial, conducted in parallel, with to arms:

Arm 1- Intervention: Tenofovir/ Emtricitabine ( 300 mg / 200 mg daily during 60 days) + Personal Protective Equipment (PPE) Arm 2- Control: Placebo (1 tablet daily during 60 days) + Personal Protective Equipment (PPE) The study will recruit 950 healthcare workers who provide clinical care to confirmed or suspected cases of COVID-19 in the emergency room, COVID wards and ICU. They will be randomized 1 to 1 to the intervention group (Tenofovir Emtricitabine + PPE), or to the control group (Placebo + PPE), with 475 participants in each group.

The randomization scheme will be computed-generated and conducted centrally. Once a potential participant agree to participate, is evaluated for eligibility and fulfill the eligibility criteria, his allocation to the masked study arms is informed to the recruiting center. The allocation and the corresponding intervention given to the participant will be identified with a random number code. Only the central pharmacist of the study will know the correspondence between this random number code and the intervention (TDF/FTC or placebo). The clinical investigators, the participants, the data managers, the analysts, and other support personnel of the study are masked to the intervention assigned to the participant.

Primary Outcome

SARS-CoV-2 infection defined as:

• Detection of SARS-CoV-2 nucleic acid using RT-PCR in any of the specimens collected during the study-follow-up
• Positive IgG antibodies against SARS-CoV-2 in any of the specimens collected during the study-follow-up Secondary outcomes
• Serious and non-serious adverse events
• Discontinuation of using the intervention (TDF/FTC or placebo) for any reason
• Adherence to TDF/FTC defined as: number of tablets taken/total number of dispensed tablets
• Severity of SARS-CoV-2 infections according to the following categories:

Asymptomatic infection Mild symptomatic SARS-CoV-2 infection with no need for hospitalization Moderate symptomatic SARS-CoV-2 infection that requires hospitalization, but no ICU Severe SARS-CoV-2 infection: dyspnea with other SARS-CoV-2 symptoms requiring ICU hospitalization Evaluation of eligibility For the assessment of eligibility, the study will perform a clinical evaluation, RT-PCR for SARS-CoV-2, IgG antibodies against SARS-CoV-2, Complete blood count, creatinine levels, phosphorus levels, AST, ALT, Bilirubin, betaHCG (women), anti HBsAg, and HIV testing.

Follow-Up

Following randomization, the participants will have four follow-up visits:

Visit 1: At 20 days, consisting in a clinical evaluation, assessment of adherence and of any adverse events.

Visit 2: At 40 days, consisting in a clinical evaluation, assessment of adherence and of any adverse events. Laboratory assessment consisting of IgG antibodies against SARS-CoV-2, and creatinine levels.

Visit 3: At 60 days, consisting in a clinical evaluation, assessment of adherence and of any adverse events. Laboratory assessment consisting of RT-PCR for SARS-CoV-2, Complete blood count, creatinine levels, AST, ALT, betaHCG.

Visit 4: At 75 days, consisting in a clinical evaluation and laboratory assessment consisting of IgG antibodies against SARS-CoV-2.

Criteria for withdrawal of the study

The presence of any of the following conditions at any time during the follow-up determine the withdrawal of the participant from the study:

• Grade 2 or higher abnormalities in the measured parameters of renal function.
• A clinical indication to initiate a drug with significant interactions with TDF/FTC
• The occurrence of any serious adverse event related with the intervention, according to the evaluation of the clinical investigators.
• The occurrence of any adverse event that determine that the participant want to interrupt the intervention.
• The decision of the participant to withdraw from the study for any reason Statistical Analysis Analysis by intention to treat, with estimation of a Hazard Ratio with 95% confidence interval, using a univariate Cox Model. In case of imbalance between the arms in relevant predictors of the outcome with will adjust them using a multivariable Cox Model.

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