Pipeline: Investigational Antiviral Therapies for COVID-19

Updated on 6/16

While no specific treatment for coronavirus disease 2019 (COVID-19) is currently available, several therapies are being investigated globally.*   


Ampligen (AIM ImmunoTech): a broad-spectrum antiviral being developed for COVID-19 in Japan. A significant survival effect was observed in a trial evaluating mice infected with the earlier Severe Acute Respiratory Syndrome (SARS) coronavirus. 

Chloroquine, Hydroxychloroquine: The Food and Drug Administration (FDA) has issued a safety alert stating that the use of these agents, either alone or in combination with azithromycin, should be limited to clinical trial settings or for treating COVID-19 patients under the FDA’s Emergency Use Authorization. NIH trial has been initiated to investigate the combination. Data from a large study showed no benefit and increased risk of ventricular arrhythmias, although the research was recently retracted due to data integrity issues. Emergency use authorization was revoked for both agents based on new information suggesting the drugs were unlikely to be beneficial. Hydroxychloroquine is being investigated for postexposure prophylaxis against COVID-19.

Danoprevir (Ascletis Pharma): a direct-acting antiviral agent being investigated in combination with ritonavir. Danoprevir is currently approved in China for the treatment of chronic hepatitis C infection.

EIDD-2801 (Ridgeback Biotherapeutics): a ribonucleoside analog that inhibits the replication of multiple RNA viruses including SARS-CoV-2. The FDA has approved an Investigational New Drug application (IND) that will allow human clinical testing. 

ENU200 (Ennaid): an orally delivered antiviral compound previously approved to treat other infections. In-silico modeling revealed that ENU200 delivers specific antiviral activity against 2 SARS-CoV-2 proteins, S glycoprotein and Mpro. The Company believes it can quickly bring ENU200 to market by treating COVID-19 in a phase 3 in-home, self-dosing clinical trial of patients with asymptomatic, mild to moderate infections.

Elsulfavirine (Viriom): a non-nucleoside reverse transcriptase inhibitor (NNRTI) being investigated in a phase 2 trial across Russia and Eastern Europe in adults with moderate manifestations of COVID-19. 

Favipiravir (Fujifilm): an antiviral agent approved in Japan for influenza treatment. announced the initiation of a phase 2 trial in the US. The study will enroll approximately 50 patients with COVID-19, in collaboration with Brigham and Women’s Hospital, Massachusetts General Hospital, and the University of Massachusetts Medical School.  

Galidesivir (BioCryst Pharmaceuticals): an adenosine nucleoside analog that acts to block viral RNA polymerase. The Company has opened enrollment into a randomized, double-blind, placebo-controlled trial to assess the safety, clinical impact, and antiviral effects of galidesivir in patients with COVID-19.

Lopinavir/ritonavir (AbbVie): recent trial results published in the New England Journal of Medicine showed that the HIV combination therapy was not associated with clinical improvement in COVID-19 patients with severe illness. Triple antiviral therapy with interferon beta-1b and ribavirin looks promising for mild to moderate infections.

Merimepodib (ViralClear Pharmaceuticals): an orally-administered broad spectrum antiviral. A phase 2 trial will be conducted at Mayo Clinic to evaluate the drug candidate, which targets RNA-dependent polymerases. In vitro data demonstrated decreased viral production of SARS-CoV-2 by over 98%.

Nitazoxanide (Romark): an investigational broad spectrum antiviral that has been shown to inhibit replication of SARS, MERS, and other coronaviruses. The Company will initiate two phase 3 clinical trials evaluating nitazoxanide for the prevention of COVID-19 and other viral respiratory illnesses in high-risk populations, including elderly residents of long-term care facilities and healthcare workers.

OT-101 (Mateon Therapeutics): a TGF-β antisense drug candidate that has demonstrated potent antiviral activity against COVID-19. According to the Company, the mechanism of action for OT-101 against COVID-19 includes inhibition of cellular binding, inhibition of viral replication and suppression of viral induced pneumonia.

Oxypurinol (XORTX Therapeutics): a new formulation of oxypurinol being evaluated as a novel treatment for acute kidney and lung injury accompanying COVID-19 infection.

Remdesivir (Gilead): an investigational nucleotide analog with broad spectrum antiviral activity. The product is being investigated in a double-blinded, placebo-controlled study sponsored by the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health. Recent data showed that the treatment was effective in patients with severe disease, shortening the time to recovery, compared with placebo. Remdesivir is also being investigated in combination with baricitinib in an NIH-sponsored trial. The FDA has granted Emergency Use Authorization for remdesivir to treat hospitalized patients.

Ribavirin for oral inhalation (Virazole; Bausch Health): a clinical trial has been initiated in Canada evaluating an investigational use of the nucleoside analog ribavirin for inhalation solution, with standard of care therapy, to treat hospitalized adult patients with respiratory distress due to COVID-19.

*Not an inclusive list. Updates will be made as more information becomes available.