Pivoting from vaccine to treatment – pandemic-changers from Pfizer, Merck, add to growing protocols

Pfizer COVID pill, Paxlovid, reduces risk of hospitalization/death by 89% in studies which were stopped so the data could be immediately submitted to the FDA to seek emergency approval in the US and EU.

Merck and Ridgeback’s Molnupiravir, a COVID-19 Antiviral pill, has received the first authorization in the world as a treatment.

With so many people vaccinated in the world, and particularly in developed countries such as the US, we will continue to see fully vaccinated people come down with breakthrough infections. Much of this is due to the variants which will continue to evolve as the virus struggles for its own existence.

While early-on treatments such as hydroxychloroquine and dexamethasone were met with skepticism, and tied up in political issues, for awhile now we have been treatment with monoclonal antibody infusions, remdesivir, regeneron, cocktails of Vitamin D, Zinc, and Vitamin C, Dexamethasone, Tocilizumab, Molnupiravir,,convalescent plasma, and yes, hydroxychloroquine.

While these are general treatments designed to boost the immune system and the body’s ability to fight off disease, antivirals would act much as the medication you can take within a short period of time of coming down with the flu – most commonly, Tamiflu.

Antiviral drugs are also different from antibiotics. Flu antivirals are prescription medicines (pills, liquid, intravenous solution, or an inhaled powder) and are not available over the counter. Antiviral drugs can make illness milder and shorten the time you are sick. They do not need to be continually redeveloped as different strains of a virus come along.

Pfizer’s Paxlovid

Pfizer’s Novel COVID-19 Oral Antiviral Treatment Candidate Reduced Risk of Hospitalization or Death by 89% in Interim Analysis of Phase 2/3 EPIC-HR Study

In a statement yesterday, Pfizer detailed their medication findings. Dosage would be once every 12 hours (2X/day) for 5 days).

• PAXLOVID™ (PF-07321332; ritonavir) was found to reduce the risk of hospitalization or death by 89% compared to placebo in non-hospitalized high-risk adults with COVID-19
• In the overall study population through Day 28, no deaths were reported in patients who received PAXLOVID™ as compared to 10 deaths in patients who received placebo
• Pfizer plans to submit the data as part of its ongoing rolling submission to the U.S. FDA for Emergency Use Authorization (EUA) as soon as possible

Pfizer today announced its investigational novel COVID-19 oral antiviral candidate,PAXLOVID™, significantly reduced hospitalization and death, based on an interim analysis of the Phase 2/3 EPIC-HR (Evaluation of Protease Inhibition for COVID-19 in High-Risk Patients) randomized, double-blind study of non-hospitalized adult patients with COVID-19, who are at high risk of progressing to severe illness. The scheduled interim analysis showed an 89% reduction in risk of COVID-19-related hospitalization or death from any cause compared to placebo in patients treated within three days of symptom onset (primary endpoint); 0.8% of patients who received PAXLOVID™ were hospitalized through Day 28 following randomization (3/389 hospitalized with no deaths), compared to 7.0% of patients who received placebo and were hospitalized or died (27/385 hospitalized with 7 subsequent deaths).

The statistical significance of these results was high (p<0.0001). Similar reductions in COVID-19-related hospitalization or death were observed in patients treated within five days of symptom onset; 1.0% of patients who received PAXLOVID™ were hospitalized through Day 28 following randomization (6/607 hospitalized, with no deaths), compared to 6.7% of patients who received a placebo (41/612 hospitalized with 10 subsequent deaths), with high statistical significance (p<0.0001). In the overall study population through Day 28, no deaths were reported in patients who received PAXLOVID™ as compared to 10 (1.6%) deaths in patients who received placebo.

At the recommendation of an independent Data Monitoring Committee and in consultation with the U.S. Food and Drug Administration (FDA), Pfizer will cease further enrollment into the study due to the overwhelming efficacy demonstrated in these results and plans to submit the data as part of its ongoing rolling submission to the U.S. FDA for Emergency Use Authorization (EUA) as soon as possible.

“Today’s news is a real game-changer in the global efforts to halt the devastation of this pandemic. These data suggest that our oral antiviral candidate, if approved or authorized by regulatory authorities, has the potential to save patients’ lives, reduce the severity of COVID-19 infections, and eliminate up to nine out of ten hospitalizations,” said Albert Bourla, Chairman and Chief Executive Officer, Pfizer. “Given the continued global impact of COVID-19, we have remained laser-focused on the science and fulfilling our responsibility to help healthcare systems and institutions around the world while ensuring equitable and broad access to people everywhere.”

If approved or authorized, PAXLOVID™, which originated in Pfizer’s laboratories, would be the first oral antiviral of its kind, a specifically designed SARS-CoV-2-3CL protease inhibitor. Upon successful completion of the remainder of the EPIC clinical development program and subject to approval or authorization, it could be prescribed more broadly as an at-home treatment to help reduce illness severity, hospitalizations, and deaths, as well as reduce the probability of infection following exposure, among adults. It has demonstrated potent antiviral in vitro activity against circulating variants of concern, as well as other known coronaviruses, suggesting its potential as a therapeutic for multiple types of coronavirus infections.

“All of us at Pfizer are incredibly proud of our scientists, who designed and developed this molecule, working with the utmost urgency to help lessen the impact of this devastating disease on patients and their communities,” said Mikael Dolsten, MD, PhD., Chief Scientific Officer and President, Worldwide Research, Development and Medical of Pfizer. “We’re thankful to all of the patients, investigators, and sites around the world who participated in this clinical trial, all with the common goal of bringing forth a breakthrough oral therapy to help combat COVID-19.”

The Phase 2/3 EPIC-HR study began enrollment in July 2021. The Phase 2/3 EPIC-SR (Evaluation of Protease Inhibition for COVID-19 in Standard-Risk Patients) and EPIC-PEP (Evaluation of Protease Inhibition for COVID-19 in Post-Exposure Prophylaxis) studies, which began in August and September 2021 respectively, were not included in this interim analysis and are ongoing.

About the Phase 2/3 EPIC-HR Study Interim Analysis

The primary analysis of the interim data set evaluated data from 1219 adults who were enrolled by September 29, 2021. At the time of the decision to stop recruiting patients, enrollment was at 70% of the 3,000 planned patients from clinical trial sites across North and South America, Europe, Africa, and Asia, with 45% of patients located in the United States. Enrolled individuals had a laboratory-confirmed diagnosis of SARS-CoV-2 infection within a five-day period with mild to moderate symptoms and were required to have at least one characteristic or underlying medical condition associated with an increased risk of developing severe illness from COVID-19. Each patient was randomized (1:1) to receive PAXLOVID™ or placebo orally every 12 hours for five days.

Merck’s Molnupiravir

Merck, known as MSD outside the United States and Canada, and Ridgeback Biotherapeutics today announced that the United Kingdom Medicines and Healthcare products Regulatory Agency (MHRA) has granted authorization in the United Kingdom (U.K.) for molnupiravir (MK-4482, EIDD-2801), the first oral antiviral medicine authorized for the treatment of mild-to-moderate COVID-19 in adults with a positive SARS-CoV-2 diagnostic test and who have at least one risk factor for developing severe illness. In the U.K., LAGEVRIO^® (lah-GEV-ree-oh) is the planned trademark for molnupiravir; the trademark for molnupiravir in other countries has not been approved. Merck announced its application with the U.S. Food and Drug Administration (FDA) for Emergency Use Authorization (EUA) of molnupiravir is under review and recently announced the European Medicines Agency has initiated a rolling review of the company’s Marketing Authorization Application. Merck is actively working to submit applications to other regulatory agencies around the world.

“The first global authorization of molnupiravir is a major achievement in Merck’s singular legacy of bringing forward breakthrough medicines and vaccines to address the world’s greatest health challenges. In pursuit of Merck’s unwavering mission to save and improve lives, we will continue to move with both rigor and urgency to bring molnupiravir to patients around the world as quickly as possible,” said Robert M. Davis, chief executive officer and president, Merck.

“As an oral therapeutic, molnupiravir offers an important addition to the vaccines and medicines deployed so far to counter the COVID-19 pandemic,” said Dr. Dean Y. Li, executive vice president and president, Merck Research Laboratories. “We are very grateful to the investigators, patients and their families for their critical contributions to the MOVe-OUT study that made this authorization possible.”

The authorization is based on positive results from a planned interim analysis from the Phase 3 MOVe-OUT clinical trial, which evaluated molnupiravir 800 mg twice-daily in non-hospitalized, unvaccinated adult patients with laboratory-confirmed mild-to-moderate COVID-19, symptom onset within five days of study randomization and at least one risk factor associated with poor disease outcomes (e.g., heart disease, diabetes).

“When we embarked on the journey to take molnupiravir from a hope to a reality, we believed we had a responsibility to move as quickly and safely as possible. We believed each day saved could save lives and limit severe disease and the global hardships of this pandemic,” said Wendy Holman, chief executive officer, Ridgeback Biotherapeutics. “It is gratifying to reach this milestone and show that the extraordinary effort of our collaborators, patients, physicians and team and the personal sacrifices made have now achieved that important goal. It is also gratifying to see the first global authorization occur in the U.K., the very place where we administered molnupiravir to the first brave human volunteer.”

About Merck’s Global Efforts to Accelerate Access to Molnupiravir Following Regulatory Authorizations or Approvals

Merck is committed to providing timely access to molnupiravir globally through our comprehensive supply and access approach, which includes investing at risk to produce millions of courses of therapy; tiered pricing based on the ability of governments to finance health care; entering into supply agreements with governments; and granting voluntary licenses to generic manufacturers and to the Medicines Patent Pool to make generic molnupiravir available in low- and middle-income countries following local regulatory authorizations or approvals.

Supply: In anticipation of the results from MOVe-OUT and the potential for regulatory authorization or approval, Merck has been producing molnupiravir at risk and expects to produce 10 million courses of treatment by the end of 2021, with at least 20 million courses to be produced in 2022.

Merck continues to discuss additional measures and collaborations to accelerate broad, global access to molnupiravir.