Low dose dexamethasone in combination with Remdesivir does not cause immune dysregulation

The administration of Remdesivir/Dexamethasone combination on T and B cell responses in patients with COVID-19 is sparse. To compare cell mediated immune response in patients treated with only Remdesivir and Remdesivir/dexamethasone combination RT-PCR positive SARS-CoV-2 patients (n=49) were enrolled. Patients not requiring O2-supplementation were on remdesivir and those requiring were on remdesivir/dexamethasone. Baseline parameters (complete blood picture, inammatory markers), T and B cells (ow cytometry: day 5 and 30) and neutralizing antibodies (chemiluminescence: day 30) were estimated. Students “t’’ test was used to evaluate the differences. given to patients requiring oxygen supplementation is safe at 4-6mg/day and showed a marked decrease in inammation and no immune dysregulation.


Introduction
COVID-19, a severe acute respiratory distress syndrome (ARDS) caused by SARS-CoV-2 resulted in unprecedented mortality worldwide [1]. Remdesivir is currently the only drug approved by FDA for the treatment of COVID-19 [2] as it is demonstrated to reduce the viral loads invitro. Hospitalized patients with moderate COVID-19 receiving 5-day Remdesivir treatment revealed better outcomes than those on standard of care [3]. Further, ACTT-1 randomized clinical trial reported reduced time to clinical recovery in severe COVID-19 patients [4] while there was no impact on 28-day mortality rate [5]. Dexamethasone a corticosteroid known for its anti-in ammatory and immunosuppressant effects [6] was shown to lower 28-day mortality in hospitalized patients needing mechanical ventilation [7] (recovery Trial). Since the pathogenesis of COVID-19 is established to be driven by viral replication early during the course and dysregulated immune response later in the course, a combination of antiviral and anti-in ammatory drug regimen might be bene cial for COVID-19 patients. However, safety and e cacy studies of combination of Remdesivir with Dexamethasone and the effect on immune responses have not been meticulously conducted in clinical trials [8]. Therefore, this study was taken up to assess the T and B cell responses in COVID-19 patients treated with a combination of Remdesivir and Dexamethasone.

Materials And Methods
Hospitalized COVID-19 patients (n=49) were enrolled in this single center, prospective, pilot study. Patients with comorbidities were excluded in order to avoid confounders. The study was approved by Institutional Ethics Committee of the Institute. All the participants had provided written informed consent. Whole blood was collected for assessing base line parameters (complete blood picture, in ammatory markers, T and B cell enumeration). Patients with hypoxia, shortness of breath and a CT severity score of > 10/25 (40% lung involvement) were administered either a combination of Remdesivir and Dexamethasone or only Remdesivir for those not requiring oxygen supplementation. Remdesivir was administered for 5 days; (day one 200 mg and day 2-5 100mg/day) and dexamethasone (4-6mg/ once daily) was given for 5days in the combination group while in hospital. Post discharge 4mg dexamethasone once daily was continued for 7-15 days. Whole blood was collected for T and B cell enumeration at day 5 and 30 and neutralizing antibodies were tested on day 30. Patients were followed-up after discharge and for occurrence of any other infections due to immunosuppression for 3 months. Laboratory investigations and in ammatory markers were evaluated employing standard protocols. Peripheral Blood Mononuclear cells (PBMCs) isolated from whole blood were stained with a cocktail of surface antibodies that included CD3 (FITC), CD4 (Percp Cy 5.5), CD8 (APC-H7), for T-Lymphocytes and CD20(PE), for B-Lymphocyte (BD Biosciences, USA) and enumerated on ow cytometer ARIA II (BD Biosciences, USA). SARS-CoV-2 S1/S2 IgG neutralizing antibodies were enumerated as described earlier [

Results
The total WBC, total lymphocyte and total neutrophil counts increased in both the groups post treatment ( Figure 1A).  Figure 1B). Furthermore, the immune cells namely CD3, CD4, CD8 and CD20 also showed an increased trend in both the groups with a comparatively higher increase in CD4 (1.98 Vs 0.81 fold) and CD8 cells (1.25 Vs 0.89 fold) in patients treated remdesivir and dexamethasone ( Figure 1C). A higher neutralizing antibody response was noted in the remdesivir and dexamethasone group (120.74±26.13 Vs 69.98±11.75; p=0.07; Figure 1D).
One patient in the Remdesivir group was deceased on day 7 and none in the Remdesivir and dexamethasone group. All the patients given combination improved and maintained the oxygen saturation levels greater than 95%, 5 days' post treatment. On follow up, at the end of 30 days, one patient in the Remdesivir and dexamethasone developed oral candidiasis and was managed with antifungal treatment. There was no evidence of mucormycosis in these patients after 3 months of follow up.

Discussion
In this pilot study, patients receiving combination of Remdesivir and dexamethasone did not show adverse effects due to administration of glucocorticoid suggesting that dexamethasone at this dose is safe in patients with COVID-19. Correction of hypoxia, maintenance of oxygen saturation >95%, decreased in ammatory markers and lower recovery time in patient requiring oxygen supplementation in the combination group demonstrates the e cacy of dexamethasone in the treatment of COVID-19.
Although RECOVERY trial demonstrated lower 28-day mortality in hospitalized patients requiring oxygen support/mechanical ventilation, our study demonstrates that administration of glucocorticoid did not cause immune cell dysregulation. In conclusion our results demonstrate the safety and e cacy of Remdesivir and Dexamethasone treatment in Covid-19 disease. Hence the combination can be administered at this dose to Covid-19 patients with moderate disease requiring oxygen supplementation.  Figure 1 Blood Counts, In ammatory markers, Immune cells and Neutralizing antibody levels in Remdesivir and Remdesivir and dexamethasone treated COVID-19 patients Panel A Shows Total WBC, absolute neutrophil and lymphocytes counts. A signi cantly higher total WBC counts post treatment with remdesivir (6060±639 Vs 9145±1034; p=0.01) and remdesivir and dexamethasone combination (6357±981 Vs 10700 Vs 1363; p=0.01) as compared to pre-treatment was noted. Likewise, Absolute neutrophil counts were also signi cantly higher pre and post treatment in both the treated groups