Favipiravir in SARS-CoV-2 Infection: Is it Worth it?

Favipiravir is a potential antiviral drug undergoing clinical trials to manage various viral infections, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Favipiravir possesses antiviral properties against RNA viruses, including SARS-CoV-2. Unfortunately, these viruses do not have authorized antiviral drugs for the management of diseases resulting from their infection, hence the dire need to accentuate the discovery of antiviral drugs that are efficacious and have a broad spectrum. Favipiravir acts primarily by blocking inward and outward movements of the virus from cells. Favipiravir is a prodrug undergoing intracellular phosphorylation and ribosylation to form an active form, favipiravir-RTP, which binds viral RNA-dependent RNA polymerase (RdRp). Considering the novel mechanism of favipiravir action, especially in managing viral infections, it is vital to pay more attention to the promised favipiravir hold in the management of SARS-CoV-2, its efficacy, and dosage regimen, and interactions with other drugs. In conclusion, favipiravir possesses antiviral properties against RNA viruses, including COVID- 19. Favipiravir is effective against SARS-CoV-2 infection through inhibition of RdRp. Pre-clinical and large-scalp prospective studies are recommended for efficacy and long-term safety of favipiravir in COVID-19.

Early treatment of Favipiravir in COVID-19 patients without pneumonia: a multicentre, open-labelled, randomized control study.

We investigated Favipiravir (FPV) efficacy in mild cases of COVID-19 without pneumonia and its effects towards viral clearance, clinical condition, and risk of COVID-19 pneumonia development. PCR-confirmed SARS-CoV-2-infected patients without pneumonia were enrolled (2:1) within 10 days of symptomatic onset into FPV and control arms. The former received 1800 mg FPV twice-daily (BID) on Day 1 and 800 mg BID 5-14 days thereafter until negative viral detection, while the latter received only supportive care. The primary endpoint was time to clinical improvement, defined by a National Early Warning Score (NEWS) of ≤1. 62 patients (41 female) comprised the FPV arm (median age: 32 years, median BMI: 22 kg/m²) and 31 patients (19 female) comprised the control arm (median age: 28 years, median BMI: 22 kg/m²). The median time to sustained clinical improvement, by NEWS, was 2 and 14 days for FPV and control arms, respectively (adjusted hazard ratio (aHR) of 2.77, 95% CI 1.57-4.88, P < .001). The FPV arm also had significantly higher likelihoods of clinical improvement within 14 days after enrolment by NEWS (79% vs. 32% respectively, P < .001). 8 (12.9%) and 7 (22.6%) patients in FPV and control arms developed mild pneumonia at a median (range) of 6.5 (1-13) and 7 (1-13) days after treatment, respectively (P = .316). All recovered well without complications. We can conclude that early treatment of FPV in symptomatic COVID-19 patients without pneumonia was associated with faster clinical improvement.Trial registration: Thai Clinical Trials Registry identifier: TCTR20200514001.

Longitudinal Analysis of Neutralizing Potency against SARS-CoV-2 in the Recovered Patients after Treatment with or without Favipiravir.

The effect of treatment with favipiravir, an antiviral purine nucleoside analog, for coronavirus disease 2019 (COVID-19) on the production and duration of neutralizing antibodies for SARS-CoV-2 was explored. There were 17 age-, gender-, and body mass index-matched pairs of favipiravir treated versus control selected from a total of 99 patients recovered from moderate COVID-19. These subjects participated in the longitudinal (>6 months) analysis of (i) SARS-CoV-2 spike protein's receptor-binding domain IgG, (ii) virus neutralization assay using authentic virus, and (iii) neutralization potency against original (WT) SARS-CoV-2 and cross-neutralization against B.1.351 (beta) variant carrying triple mutations of K417N, E484K, and N501Y. The results demonstrate that the use of favipiravir: (1) significantly accelerated the elimination of SARS-CoV-2 in the case vs. control groups (p = 0.027), (2) preserved the generation and persistence of neutralizing antibodies in the host, and (3) did not interfere the maturation of neutralizing potency of anti-SARS-CoV-2 and neutralizing breadth against SARS-CoV-2 variants. In conclusion, treatment of COVID-19 with favipiravir accelerates viral clearance and does not interfere the generation or maturation of neutralizing potency against both WT SARS-CoV-2 and its variants.

Efficacy and safety of favipiravir plus interferon-beta versus lopinavir/ritonavir plus interferon-beta in moderately ill patients with COVID-19: A randomized clinical trial.

Favipiravir (FVP), lopinavir/ritonavir (LPV/RTV), and interferon-beta (INF-beta) are considered as potential treatments for COVID-19. We examined the efficacy and safety of FVP and INF-beta compared to LPV/RTV and INF-beta combinations for the treatment of SARS-CoV-2. It was a single-center randomized clinical trial. Eligible patients were randomized to receive FVP plus INF-beta versus LPV/RTV plus INF-beta. The primary endpoint was the viral clearance after seven days of randomization. ICU admission, length of stay (LOS) in hospital, in-hospital mortality, and the incidence of adverse events were also measured. This trial was registered on the Iranian Registry of Clinical Trials (IRCT20200506047323N3). Patients were randomly allocated to the FVP (n = 33) and LPV/RTV (n = 33) groups. The viral clearance on Day seven was not significantly different between the FVP (31.1%) and the LPV/RTV groups (16.1%). The rate of ICU admission and likewise the in-hospital mortality in the FVP group (12.5% and 6.3%, respectively) were similar to the LPV/RTV groups (19.4% and 19.4%, respectively). The median LOS in the hospital was also not different (6.8 days [interquartile range; IQR = 5.0-11.0] in the FVP and (8.0 days [IQR = 5.5-12.5]) in LPV/RTV groups (p = 0.140). Adverse events were observed in 25.0% of FVP and 32.3% of LPV/RTV groups. The combination therapy with FVP did not exert a higher efficacy compared to the combination regimen of LPV/RTV. However, both treatment regimens demonstrated a mild profile of adverse events.

Core-shell nanocomposite of flower-like molybdenum disulfide nanospheres and molecularly imprinted polymers for electrochemical detection of anti COVID-19 drug favipiravir in biological samples.

A novel electrochemical sensor is reported for the detection of the antiviral drug favipiravir based on the core-shell nanocomposite of flower-like molybdenum disulfide (MoS2) nanospheres and molecularly imprinted polymers (MIPs). The MoS2@MIP core-shell nanocomposite was prepared via the electrodeposition of a MIP layer on the MoS2 modified electrode, using o-phenylenediamine as the monomer and favipiravir as the template. The selective binding of target favipiravir at the MoS2@MIP core-shell nanocomposite produced a redox signal in a concentration dependent manner, which was used for the quantitative analysis. The preparation process of the MoS2@MIP core-shell nanocomposite was optimized. Under the optimal conditions, the sensor exhibited a wide linear response range of 0.01 ~ 100 nM (1.57*10-6 ~ 1.57*10-2 µg mL-1) and a low detection limit of 0.002 nM (3.14*10-7 µg mL-1). Application of the sensor was demonstrated by detecting favipiravir in a minimum amount of 10 µL biological samples (urine and plasma). Satisfied results in the recovery tests indicated a high potential of favipiravir monitoring in infectious COVID-19 samples.

Efficacy of favipiravir in adults with mild COVID-19: a randomized, double-blind, multicentre, placebo-controlled clinical trial.

OBJECTIVE: To evaluate whether favipiravir reduces the time to viral clearance as documented by negative RT-PCR results for severe acute respiratory syndrome coronavirus 2 in mild cases of coronavirus disease 2019 (COVID-19) compared to placebo. METHODS: In this randomized, double-blinded, multicentre, and placebo-controlled trial, adults with PCR-confirmed mild COVID-19 were recruited in an outpatient setting at seven medical facilities across Saudi Arabia. Participants were randomized in a 1:1 ratio to receive either favipiravir 1800 mg by mouth twice daily on day 1 followed by 800 mg twice daily (n = 112) or a matching placebo (n = 119) for a total of 5 to 7 days. The primary outcome was the effect of favipiravir on reducing the time to viral clearance (by PCR test) within 15 days of starting the treatment compared to the placebo group. The trial included the following secondary outcomes: symptom resolution, hospitalization, intensive care unit admissions, adverse events, and 28-day mortality. RESULTS: Two hundred thirty-one patients were randomized and began the study (median age, 37 years; interquartile range (IQR): 32-44 years; 155 [67%] male), and 112 (48.5%) were assigned to the treatment group and 119 (51.5%) into the placebo group. The data and safety monitoring board recommended stopping enrolment because of futility at the interim analysis. The median time to viral clearance was 10 days (IQR: 6-12 days) in the favipiravir group and 8 days (IQR: 6-12 days) in the placebo group, with a hazard ratio of 0.87 for the favipiravir group (95% CI 0.571-1.326; p = 0.51). The median time to clinical recovery was 7 days (IQR: 4-11 days) in the favipiravir group and 7 days (IQR: 5-10 days) in the placebo group. There was no difference between the two groups in the secondary outcome of hospital admission. There were no drug-related severe adverse events. CONCLUSION: In this clinical trial, favipiravir therapy in mild COVID-19 patients did not reduce the time to viral clearance within 15 days of starting the treatment.

Favipiravir in the Battle with Respiratory Viruses.

Among antiviral drugs, the vast majority targets only one or two related viruses. The conventional model, one virus - one drug, significantly limits therapeutic options. Therefore, in the strategy of controlling viral infections, there is a necessity to develop compounds with pleiotropic effects. Favipiravir (FPV) emerged as a strong candidate to become such a drug. The aim of the study is to present up-to-date information on the role of favipiravir in the treatment of viral respiratory infections. The anti-influenza activity of favipiravir has been confirmed in cell culture experiments, animal models, and clinical trials. Thoroughly different - from the previously registered drugs - mechanism of action suggests that FVP can be used as a countermeasure for the novel or re-emerging influenza virus infections. In recent months, favipiravir has been broadly investigated due to its potential efficacy in the treatment of COVID-19. Based on preclinical and clinical studies and a recently published meta-analysis it seems that favipiravir may be a promising antiviral drug in the treatment of patients with COVID-19. FPV is also effective against other RNA respiratory viruses and may be a candidate for the treatment of serious infections caused by human rhinovirus, respiratory syncytial virus, metapneumovirus, parainfluenza viruses and hantavirus pulmonary syndrome.

Antiviral therapy for COVID-19: Derivation of optimal strategy based on past antiviral and favipiravir experiences.

Favipiravir, a broad-spectrum RNA-dependent RNA polymerase inhibitor, inhibits the replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at significantly lower concentrations than the plasma trough levels achieved by the dosage adopted for influenza treatment and exhibits efficacy against coronavirus disease 2019 (COVID-19) pneumonia. Although high doses of favipiravir are required due to the molecule being a purine analog, its conversion into the active form in infected cells with active viral RNA synthesis enhances the antiviral specificity and selectivity as a chain terminator with lethal mutagenesis. Another characteristic feature is the lack of generation of favipiravir-resistant virus. COVID-19 pneumonia is caused by strong cell-mediated immunity against virus-infected cells, and the inflammatory response induced by adaptive immunity continues to peak for 3 to 5 days despite antiviral treatment. This has also been observed in herpes zoster (HZ) and cytomegalovirus (CMV) pneumonia. Inflammation due to an immune response may mask the effectiveness of favipiravir against COVID-19 pneumonia. Favipiravir significantly shortened the recovery time in patients with mild COVID-19 pneumonia by 3 days with the start of treatment by the 5th day of symptom onset. Since both CMV and COVID-19 pneumonia are caused by adaptive immunity and prevention of cytomegalovirus pneumonia is the standard treatment due to difficulties in treating refractory CMV pneumonia, COVID-19 pneumonia should be prevented with early treatment as well. In the present study, we have comprehensively reviewed the optimal antiviral therapy for COVID-19 based on clinical trials of favipiravir for the treatment of COVID-19 pneumonia and the concurrently established therapies for other viral infections, particularly HZ and CMV pneumonia. Optimally, antivirals should be administered immediately after COVID-19 diagnosis, similar to that after influenza diagnosis, to prevent COVID-19 pneumonia and complications resulting from microangiopathy.

Therapeutic dilemmas in addressing SARS-CoV-2 infection: Favipiravir versus Remdesivir.

Coronavirus disease 2019 (COVID-19) represents an unmet clinical need, due to a high mortality rate, rapid mutation rate in the virus, increased chances of reinfection, lack of effectiveness of repurposed drugs and economic damage. COVID-19 pandemic has created an urgent need for effective molecules. Clinically proven efficacy and safety profiles have made favipiravir (FVP) and remdesivir (RDV) promising therapeutic options for use against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Even though both are prodrug molecules with an antiviral role based on a similar mechanism of action, differences in pharmacological, pharmacokinetic and pharmacotoxicological mechanisms have been identified. The present study aims to provide a comprehensive comparative assessment of FVP and RDV against SARS-CoV-2 infections, by centralizing medical data provided by significant literature and authorized clinical trials, focusing on the importance of a better understanding of the interactions between drug molecules and infectious agents in order to improve the global management of COVID-19 patients and to reduce the risk of antiviral resistance.

The incidence, clinical characteristics, and outcome of COVID-19 in a prospectively followed cohort of patients with Behçet's syndrome.

Initial case series of small number of patients at the beginning of the pandemic reported a rather guarded prognosis for Behçet's syndrome (BS) patients infected with SARS-CoV-2. In this prospective study, we describe the incidence, clinical characteristics, disease course, management, and outcome in a large cohort of BS patients with laboratory-confirmed infection of SARS-CoV-2. We defined a cohort of 1047 registered BS patients who were aged between 16 and 60 years and seen routinely before the pandemic at the multidisciplinary outpatient clinic. We followed prospectively this cohort from beginning of April 2020 until the end of April 2021. During 13 months of follow-up, of the 1047 (599 M/448 F) patients, 592 (56.5%) were tested for SARS-CoV-2 PCR at least once and 215 (20.5%; 95% CI 0.18-0.23) were tested positive. We observed 2 peaks which took place in December 2020 and April 2021. Of the 215 PCR positive patients, complete information was available in 214. Of these 214, 14 (6.5%) were asymptomatic for COVID-19. In the remaining, the most common symptoms were anosmia, fatigue, fever, arthralgia, and headache. A total of 40 (18.7%) had lung involvement, 25 (11.7%) were hospitalized, 1 was admitted to the intensive care unit while none died. Favipiravir was the most prescribed drug (74.3%), followed by colchicine (40.2%), and hydroxychloroquine (20.1%) in the treatment of COVID-19. After COVID-19, 5 patients (2.3%) were given supplemental O2 and 31 (14.5%) antiaggregant or anticoagulants. During COVID-19, of the 214 PCR positive patients, 116 (54.2%) decreased the dose of their immunosuppressives or stopped taking completely; 36 (16.8%) experienced a BS flare which was mostly oral ulcers (10.3%). None of the patients reported a thrombotic event. A total of 93 (43.5%) patients reported BS flares after a median 45 days of COVID-19 infection and this was found to be significantly associated with immunosuppressive drug discontinuation. Multiple regression analysis adjusted for age and gender indicated that smoking and using interferon-alpha decreased the likelihood of getting COVID-19. The incidence and severity of COVID-19 did not differ between those who were using colchicine or not. The cumulative incidence of COVID-19 in this prospectively followed cohort of BS patients was almost two folds of that estimated for the general population living in Istanbul, Turkey, however, the clinical outcome of COVID-19 was not severe and there was no mortality. The protective effect of smoking and interferon deserves further investigation. On the other hand, colchicine did not have any positive or negative effect against COVID-19. Significant number of patients flared after COVID-19, however, this was significantly associated with immunosuppressive discontinuation during the infection. Contrary to our previous observations, COVID-19 did not seem to exacerbate thrombotic events during or after the infection.

Human genetic risk of treatment with antiviral nucleoside analog drugs that induce lethal mutagenesis: The special case of molnupiravir.

This review considers antiviral nucleoside analog drugs, including ribavirin, favipiravir, and molnupiravir, which induce genome error catastrophe in SARS-CoV or SARS-CoV-2 via lethal mutagenesis as a mode of action. In vitro data indicate that molnupiravir may be 100 times more potent as an antiviral agent than ribavirin or favipiravir. Molnupiravir has recently demonstrated efficacy in a phase 3 clinical trial. Because of its anticipated global use, its relative potency, and the reported in vitro "host" cell mutagenicity of its active principle, ß-d-N4-hydroxycytidine, we have reviewed the development of molnupiravir and its genotoxicity safety evaluation, as well as the genotoxicity profiles of three congeners, that is, ribavirin, favipiravir, and 5-(2-chloroethyl)-2'-deoxyuridine. We consider the potential genetic risks of molnupiravir on the basis of all available information and focus on the need for additional human genotoxicity data and follow-up in patients treated with molnupiravir and similar drugs. Such human data are especially relevant for antiviral NAs that have the potential of permanently modifying the genomes of treated patients and/or causing human teratogenicity or embryotoxicity. We conclude that the results of preclinical genotoxicity studies and phase 1 human clinical safety, tolerability, and pharmacokinetics are critical components of drug safety assessments and sentinels of unanticipated adverse health effects. We provide our rationale for performing more thorough genotoxicity testing prior to and within phase 1 clinical trials, including human PIG-A and error corrected next generation sequencing (duplex sequencing) studies in DNA and mitochondrial DNA of patients treated with antiviral NAs that induce genome error catastrophe via lethal mutagenesis.

Visual classification of three computed tomography lung patterns to predict prognosis of COVID-19: a retrospective study.

BACKGROUND: Quantitative evaluation of radiographic images has been developed and suggested for the diagnosis of coronavirus disease 2019 (COVID-19). However, there are limited opportunities to use these image-based diagnostic indices in clinical practice. Our aim in this study was to evaluate the utility of a novel visually-based classification of pulmonary findings from computed tomography (CT) images of COVID-19 patients with the following three patterns defined: peripheral, multifocal, and diffuse findings of pneumonia. We also evaluated the prognostic value of this classification to predict the severity of COVID-19. METHODS: This was a single-center retrospective cohort study of patients hospitalized with COVID-19 between January 1st and September 30th, 2020, who presented with suspicious findings on CT lung images at admission (n = 69). We compared the association between the three predefined patterns (peripheral, multifocal, and diffuse), admission to the intensive care unit, tracheal intubation, and death. We tested quantitative CT analysis as an outcome predictor for COVID-19. Quantitative CT analysis was performed using a semi-automated method (Thoracic Volume Computer-Assisted Reading software, GE Health care, United States). Lungs were divided by Hounsfield unit intervals. Compromised lung (%CL) volume was the sum of poorly and non-aerated volumes (- 500, 100 HU). We collected patient clinical data, including demographic and clinical variables at the time of admission. RESULTS: Patients with a diffuse pattern were intubated more frequently and for a longer duration than patients with a peripheral or multifocal pattern. The following clinical variables were significantly different between the diffuse pattern and peripheral and multifocal groups: body temperature (p = 0.04), lymphocyte count (p = 0.01), neutrophil count (p = 0.02), c-reactive protein (p < 0.01), lactate dehydrogenase (p < 0.01), Krebs von den Lungen-6 antigen (p < 0.01), D-dimer (p < 0.01), and steroid (p = 0.01) and favipiravir (p = 0.03) administration. CONCLUSIONS: Our simple visual assessment of CT images can predict the severity of illness, a resulting decrease in respiratory function, and the need for supplemental respiratory ventilation among patients with COVID-19.

Effects of hydroxychloroquine and favipiravir on clinical course in outpatients with COVID-19

Background/aim: Due to the importance of early outpatient treatment to prevent hospitalization and disease progression, we examined the effects of hydroxychloroquine and favipiravir, which were initiated in early period, on the clinical course of COVID-19 outpatients. Materials and methods: Data of confirmed COVID-19 outpatients over a 4-month period were analyzed retrospectively. Public Health Management System (HSYS) was used for the case-based follow-up. Patients on antiviral therapy for at least five days, including hydroxychloroquine and / or favipiravir and patients who were followed-up for 30 days were included in this analysis. Results: We enrolled 1489 patients in this study. Overall, 775 (52%) patients were male and a mean age of patients was 38.9 ± 11.1 years. Of these patients, 537 of them were received favipiravir, 545 of them were received hydroxychloroquine and 407 of them were received both favipiravir and hydroxychloroquine. Symptoms improvement on the 14th day of follow-up was 1.8 times higher in the group of patients receiving hydroxychloroquine compared to patients who received favipiravir (p = 0.003). On the 3rd day of follow- up, PCR negativity rate was higher in patients who received hydroxychloroquine (p = 0.004). Hospitalization rates were similar in patients receiving favipiravir and hydroxychloroquine (p = 0.144). However, in the presence of pneumonia at the time of diagnosis, the hospitalization rate was 6.6 times higher in patients who received favipiravir than those who received hydroxychloroquine. Conclusion: The subgroups of patients treated with hydroxychloroquine and/or favipiravir did not have similar disease severities in our study. Therefore, further studies with homogeneous patient groups to be arranged prospectively are needed.

[Preliminary clinical analysis of direct renin inhibitor aliskiren in the treatment of severe coronavirus disease 2019 patients with hypertension].

Objective: To explore the feasibility of direct renin inhibitor aliskiren for the treatment of severe or critical coronavirus disease 2019 (COVID-19) patients with hypertension. Methods: The antihypertensive effects and safety of aliskiren was retrospectively analyzed in three severe and one critical COVID-19 patients with hypertension. Results: Four patients, two males and two females, with an average age of 78 years (66-87 years), were referred to hospital mainly because of respiratory symptoms. Three were diagnosed by positive novel coronavirus 2019 (2019-nCoV) nucleic acid or antibody, and the critical patient with cardiac insufficiency was clinically determined. Two patients were treated with calcium channel antagonist (CCB), one with angiotensin converting enzyme inhibitor (ACEI), and one with angiotensin Ⅱ receptor antagonist (ARB). After admission, ACEI and ARB were discontinued, one patient with heart failure was treated by aliskiren combined with diuretic.Three patients were treated with aliskiren combined with CCB among whom two withdrew CCB due to low blood pressure after 1 to 2 weeks. Based on comprehensive treatment including antiviral and oxygenation treatment, blood pressure was satisfactorily controlled by aliskiren after three to four weeks without serious adverse events. All patients were finally discharged. Conclusion: Our preliminary clinical data shows that antihypertensive effect of aliskiren is satisfactory and safe for severe COVID-19 patients complicated with hypertension.

Comparison of demographic and clinical characteristics of hospitalized COVID-19 patients with severe/critical illness in the first wave versus the second wave.

Due to current advances and growing experience in the management of coronavirus Disease 2019 (COVID-19), the outcome of COVID-19 patients with severe/critical illness would be expected to be better in the second wave compared with the first wave. As our hospitalization criteria changed in the second wave, we aimed to investigate whether a favorable outcome occurred in hospitalized COVID-19 patients with only severe/critical illness. Among 642 laboratory-confirmed hospitalized COVID-19 patients in the first wave and 1121 in the second wave, those who met World Health Organization (WHO) definitions for severe or critical illness on admission or during follow-up were surveyed. Data on demographics, comorbidities, C-reactive protein (CRP) levels on admission, and outcomes were obtained from an electronic hospital database. Univariate analysis was performed to compare the characteristics of patients in the first and second waves. There were 228 (35.5%) patients with severe/critical illness in the first wave and 681 (60.7%) in the second wave. Both groups were similar in terms of age, gender, and comorbidities, other than chronic kidney disease. Median serum CRP levels were significantly higher in patients in the second wave compared with those in the first wave [109 mg/L (interquartile range [IQR]: 65-157) vs. 87 mg/L (IQR: 39-140); p < 0.001]. However, intensive care unit admission and mortality rates were similar among the waves. Even though a lower mortality rate in the second wave has been reported in previous studies, including all hospitalized COVID-19 patients, we found similar demographics and outcomes among hospitalized COVID-19 patients with severe/critical illness in the first and second wave.

Complete response in a frail patient with high-grade B-cell lymphoma to only one cycle of R-CHOP or to prolonged COVID-19?

BACKGROUND: COVID-19 infection increases mortality in hematological malignancies. In a large meta-analysis, patients aged 60 years and older had a significantly higher risk of death than patients under 60 years of age [1]. Furthermore, a high risk of death and reduced survival in patients receiving B cell depletion therapy with prolonged COVID-19 infection was reported in a recent study [2]. High-grade B-cell lymphomas are classified as morphologically aggressive lymphomas with the presence of a high mitotic index and Ki-67 proliferation rates. They demonstrate aggressive behavior clinically as well as morphologically, and COVID-19 infection is an important factor that increases mortality in these patients. Herein, we present an elderly patient with a diagnosis of high-grade B-cell lymphoma, in whom a complete response was observed after prolonged COVID-19 infection. CASE SUMMARY: An 81-year-old female patient received her first cycle of R-CHOP (rituximab, cyclophosphamide, vincristine, and prednisolone) treatment after being diagnosed with high- grade B-cell lymphoma. After being discharged from the hospital, the patient was referred to the emergency department with complaints of fever and fatigue when she came for the second cycle of chemotherapy. Her COVID-19 PCR test was found positive. She was admitted to the infectious diseases service and favipiravir treatment was started. On the 24th day of hospitalization, it was decided to perform interim FDG-PET/CT (Fluorodeoxyglucose - Positron Emission Tomography/Computed Tomography) scan at a time that her PCR (Polymerase Chain Reaction) test was still positive. A complete metabolic response was detected in her imaging. On the 26th day, the PCR test became negative and the patient was transferred to the oncology service and received the second cycle of R-CHOP treatment. CONCLUSION: Our case emphasizes that antitumor effect could be seen in a patient with SARS-CoV-2 infection and a hematologic malignancy. It also highlights being alert to prolonged COVID-19 infection in patients receiving B-cell depletion therapy.