Virus World

The drug maker will seek authorization for molnupiravir, the first drug of its kind for Covid. Experts said such pills could be a powerful tool against the virus.  The drug maker Merck said on Friday that it would seek authorization for the first antiviral pill for Covid after its drug, known as molnupiravir, was shown in a clinical trial to cut the risk of hospitalization or death in half when given to high-risk people early in their infections. The treatment could become the first in a wave of antiviral pill products, which experts say could offer a powerful new tool in efforts to tame the pandemic, as they could reach more people than the antibody treatments that are being widely used in the United States for similar patients. “I think it will translate into many thousands of lives being saved worldwide, where there’s less access to monoclonal antibodies, and in this country, too,” said Dr. Robert Shafer, an infectious disease specialist and expert on antiviral therapy at Stanford University. Late-stage study results of two other antiviral pills, one developed by Pfizer and the other by Atea Pharmaceuticals and Roche, are expected within the next few months.  The Merck drug, which is designed to stop the coronavirus from replicating, is to be taken as four capsules twice a day for five days.

Merck said an independent board of experts monitoring its study data had recommended that its trial be stopped early because the drug’s benefit to patients had proved so convincing. The company said that the Food and Drug Administration had agreed with that decision.  For the research, the monitors looked at data through early August, when the study had enrolled 775 volunteers in the United States and overseas. For volunteers who received the drug, their risk of being hospitalized or dying fell 50 percent, without any concerning side effects, compared with those who received placebo pills, Merck said in a news release announcing the findings. Seven percent of volunteers in the group that received the drug were hospitalized, and none of them died, compared with a 14 percent rate of hospitalization and death — including eight deaths — in the group that received the placebo. The Merck pill’s efficacy was lower than that of monoclonal antibody treatments, which mimic antibodies that the immune system generates naturally when fighting the virus. Those drugs have been in high demand recently, but they are expensive, are typically given intravenously, and have proved cumbersome and labor-intensive for hospitals and clinics to administer. Studies have shown that they reduce hospitalizations and deaths 70 to 85 percent in similar high-risk Covid patients. 

Still, Angela Rasmussen, a virologist and research scientist at the Vaccine and Infectious Disease Organization at the University of Saskatchewan, said that antiviral pills could have a greater impact by virtue of reaching more people. “If that holds up at the population scale,” she said, “that is going to translate to an objectively larger number of lives saved potentially with this drug,” adding that, “Maybe it isn’t doing the same numbers as the monoclonal antibodies, but it’s still going to be huge.” The federal government has placed advance orders for 1.7 million courses of Merck’s drug, at a price of about $700 per patient. That is about one-third of the current cost of a monoclonal antibody treatment. Merck — which is developing the pill with its partner, Ridgeback Biotherapeutics of Miami — has not said which patients it plans to ask the F.D.A. to approve the drug for. It may be initially approved for the limited group of patients who are eligible to receive monoclonal antibody treatments: possibly older people and those with medical conditions that put them at high risk for bad outcomes from Covid. But experts said they expected that the drug might eventually be used more widely, in many people who test positive for the virus. If authorized, Merck’s drug would be the second antiviral treatment for Covid. The first, remdesivir, must be infused and has lost favor among clinicians as studies have suggested that it offers only modest benefit for Covid patients.

The last time the world needed an antiviral medicine as quickly as possible, Daria Hazuda, vice president of infectious disease and vaccine discovery research at Merck, answered the call. Around 150,000 Americans were infected with HIV each year when rates peaked in the mid-1980s, and by the year 2000 nearly 500,000 people had died of AIDS in the U.S. Hazuda’s research at the time focused on HIV’s ability to insert its genetic material into the the human genome. Her lab developed a novel way to target that process with a drug called raltegravir, which was approved for use in 2007 and is still used today.  Now, she hopes to develop a drug for COVID-19 — at a substantially faster pace.  While most of the world’s attention is currently laser focused on getting vaccines to more people to stem the spread of the coronavirus, there’s also significant pressure on scientists to find a cure.  Doctors have some medications they can use to treat the effects of COVID-19, but developing a drug that targets the virus itself is a complex and costly procedure. More than a year into the pandemic only one antiviral treatment — remdesivir — is currently recommended for use in the U.S., and experts say it is not nearly effective enough. “Vaccine manufacturers are making next generation vaccines to try and stay one step ahead, but it is unpredictable. So you need other interventions to address the potential evolution of the virus,” Hazuda said. She and her team, along with researchers at Miami-based Ridgeback Biotherapeutics, worked seven days a week in the spring of 2020 to find a possible treatment for COVID-19 and prepare for the clinical trials necessary to prove its safety and effectiveness. Their drug, molnupiravir, is one of two powerful medicines to treat COVID-19 that are nearing the end of clinical testing.  “The day started really early and ended really late at night,” Hazuda said. “But there was a tremendous sense of mission. Everybody wanted to help even though they were exhausted. There was so much we all had to do.” Scientists are hopeful that new drugs designed to stop the virus’ deadly reproduction could reduce hospitalizations and deaths from COVID-19. The drugs offer hope and a contingency plan for unvaccinated individuals, particularly in low-income countries lagging far behind in the race to vaccinate. 

Chasing a moving target

Viruses mutate constantly, making it challenging to find a medicine that will not just work, but continue to work as the virus morphs. Mutations can change the shape of viruses’ proteins and thereby make them resistant to drugs. The hunt for effective antivirals is largely a hunt for a “conserved target,” such as a protein that rarely changes its shape even as the virus mutates.  Since scientists shared the sequenced genome of the novel coronavirus in January 2020 — detailing the specific genetic information and proteins of the virus — researchers have worked at breakneck speed to find a targeted medicine. Hazuda’s experience with HIV and Hepatitis C helped her team quickly rule out targets in the SARS-CoV-2 structure that were likely to change as the virus mutated and focus instead on “very highly conserved targets to minimize the potential of developing resistance,” she said.  Antiviral medications often target a virus during the process of replication, when it uses our cells’ resources to make copies of itself — leading to cell damage and the release of more virus. By early March of last year, Hazuda had narrowed her search to compounds aimed at proteins that could copy the virus’s genetic material. Her team came across a pre-clinical publication from an Emory University scientist on molnupiravir, a compound initially developed for influenza and other viruses. Research suggested the compound could make it harder for the virus to replicate itself by interrupting the RNA polymerase enzyme, which acts like a copy machine for the viral genome. In various academic labs, molnupiravir has demonstrated activity against flu and many different types of coronavirus, including MERS and the common cold.  “We were very interested in finding an agent that would have the potential to be not only active against CoV-2, but potential future outbreaks or pandemics caused by other coronaviruses,” Hazuda said. Because Ridgeback Biotherapeutics had the rights to molnupiravir, Merck began collaborating with the smaller pharmaceutical company to test the safety of the compound and prepare it for clinical studies.  The idea is that molnupiravir could be taken as an oral pill by symptomatic patients who test positive for COVID-19, before their illness is severe enough to require going to a hospital. The hope is that it can stop the virus in its tracks, before it can replicate uncontrollably and cause a person to become more sick. One phase 2 clinical study showed that molnupiravir is unlikely to significantly change the illness of those people who are hospitalized with COVID-19, but Hazuda is hopeful that phase 3 trials — expected to conclude by the end of the year — will demonstrate its effectiveness as a treatment that can be used outside of the hospital for people with mild to moderate cases.

Adolfo Garcia-Sastre, the director of the Global Health and Emerging Pathogens Institute at Icahn School of Medicine at Mount Sinai, also spent the spring of 2020 looking for a medication that could thwart the coronavirus’ lifecycle, but at a different stage. He sought a drug that influences the human proteins that the virus uses to build its components.  Because viruses hijack human cells and use their proteins (called factors) and other materials for their own purpose, identifying the factors they rely on can be a first step toward halting their actions.  Garcia-Sastre’s collaborators at the Quantitative Biosciences Institute at the University of California, San Francisco, identified more than 300 human factors most likely to make an impact on viral replication. Then, his lab tested around 90 drugs that are known to affect these factors. They landed on plitidepsin, an injectable medicine developed by Spain’s PharmaMar and used in patients with multiple myeloma, a type of blood cancer. It was shown to interfere with the function of a human factor called eEF1A, which the virus uses in the assembly of  its proteins. So far, plitidepsin seems to overcome some of the difficulties in finding a drug that targets virus replication. One is that often their effectiveness in the lab or in animal testing doesn’t carry over to humans. Another is toxicity: The concentrations required can cause undesired effects in human cells. Plitidepsin passed the critical phase 1 clinical trial conducted in Spain, showing that toxicity is not a barrier to use. The ongoing phase 3 clinical trial will show whether plitidepsin decreased days of hospitalization for COVID-19 patients.  The study, expected to be completed in August, will compare plitidepsin’s effectiveness to remdesivir, the current standard of care, which also works by inhibiting replication and can shorten hospitalization for COVID-19 patients by four days, on average. Where remdesivir has fallen short on decreasing the deadliness of the virus, Garcia-Sastre hopes plitidepsin will demonstrate live-saving potential.

The cost of discovery

While doctors have blood thinners and steroids to treat the symptoms of a raging COVID-19 illness, developing a new medicine that specifically targets the virus itself can take many years, explained Bhaven Sampat, an economist and associate professor at the Department of Health Policy and Management at the Mailman School of Public Health at Columbia University.  By repurposing an existing medicine and using already-developed compounds, both Garcia-Sastre and Hazuda shaved precious time off the drug development process. Piggybacking off already identified candidates also helps sidestep some of the cost spent on basic research. “That’s particularly useful because you don’t have to reinvent the wheel in a way,” Sampat said. Remdesivir, so far the only antiviral approved for COVID-19, benefited from the same leg up. Developed nearly a decade ago and shown effective against other coronaviruses including Ebola, SARS and MERS, it was fast tracked for use against COVID-19 and greenlit by the FDA in October 2020.  Another existing drug, ivermectin, may also have potential against SARS-CoV-2. A May meta-analysis suggests it could speed recovery and reduce mortality from COVID-19. The idea is controversial; some experts are unconvinced while proponents are eager to put it to use as a cheap, effective treatment. The anti-parasitic, developed by Merck in the 1980s, is no longer under patent. The company has contended there is not sufficient evidence for its use against COVID. Merck declined to respond to PBS NewHour’s request for comment. Developing a new drug oftentimes costs more than $1 billion dollars, a financial and technological burden typically shared by federally and grant-supported research labs (often at universities), which do basic research to identify drug candidates, and pharmaceutical companies, which bring medicines through expensive clinical trials to market.....

KENILWORTH, N.J.--(BUSINESS WIRE)--Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced it has entered into a procurement agreement with the United States government for molnupiravir (MK-4482). Molnupiravir is currently being evaluated in a Phase 3 clinical trial, the MOVe-OUT study, for the treatment of non-hospitalized patients with laboratory-confirmed COVID-19 and at least one risk factor associated with poor disease outcomes. Merck is developing molnupiravir in collaboration with Ridgeback Biotherapeutics. “Merck is pleased to collaborate with the U.S. government on this new agreement that will provide Americans with COVID-19 access to molnupiravir – an investigational oral therapy being studied for outpatient use early in the course of disease – if it is authorized or approved,” said Rob Davis, president, Merck. “In addition to this agreement with the U.S. government, we are actively engaged in numerous efforts to make molnupiravir available globally to fulfill Merck’s commitment to widespread access.” Through the agreement, if molnupiravir receives Emergency Use Authorization (EUA) or approval by the U.S. Food and Drug Administration (FDA), Merck will receive approximately $1.2 billion to supply approximately 1.7 million courses of molnupiravir to the United States government. Merck has been investing at risk to support development and scale-up production of molnupiravir and expects to have more than 10 million courses of therapy available by the end of 2021.

Merck also plans to submit applications for emergency use or approval to regulatory bodies outside of the U.S. and is currently in discussions with other countries interested in advance purchase agreements for molnupiravir. Merck is committed to providing timely access to molnupiravir globally and intends to implement a tiered pricing approach based on World Bank data that recognizes countries’ relative ability to finance their public health response to the pandemic. As part of its access strategy, Merck has also entered into non-exclusive voluntary licensing agreements for molnupiravir with established generic manufacturers to accelerate availability of molnupiravir in 104 low- and middle-income countries (LMICs) following approvals or emergency authorization by local regulatory agencies. In addition to developing molnupiravir, Merck is contributing to the pandemic response by collaborating with Johnson & Johnson to support the manufacture of its COVID-19 vaccine. This procurement of molnupiravir will be supported in whole or in part with federal funds from the Department of Health and Human Services; Office of the Assistant Secretary for Preparedness and Response; Biomedical Advanced Research and Development Authority, in collaboration with the DOD Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense (JPEO-CBRND) under contract number W911QY21C0031.

About Molnupiravir

Molnupiravir (EIDD-2801/MK-4482) is an investigational, orally bioavailable form of a potent ribonucleoside analog that inhibits the replication of multiple RNA viruses including SARS-CoV-2, the causative agent of COVID-19. Molnupiravir has been shown to be active in several models of SARS-CoV-2, including for prophylaxis, treatment and prevention of transmission, as well as SARS-CoV-1 and MERS. EIDD-2801 was invented at Drug Innovations at Emory (DRIVE), LLC, a not-for-profit biotechnology company wholly owned by Emory University, and with partial funding support from the U.S. government. Since licensed by Ridgeback, all funds used for the development of EIDD-2801 by Ridgeback have been provided by Wayne and Wendy Holman and Merck. The Phase 3 portion (Part 2) of the MOVe-OUT study, evaluating the potential of molnupiravir to reduce the risk of hospitalization or death, is ongoing. Merck currently anticipates that, pending favorable results from MOVe-OUT, the earliest possible submission for an Emergency Use Authorization for molnupiravir will be in the second half of 2021. Merck and Ridgeback Biotherapeutics plan to share further findings from the ongoing molnupiravir development program with regulatory agencies as they become available. For more information on the molnupiravir clinical trial please visit https://merckcovidresearch.com/. In addition, Merck plans to initiate a clinical program to evaluate molnupiravir for post- exposure prophylaxis in the second half of 2021....

Merck has largely stayed out of the COVID-19 battle, but exploded into it with three major deals and collaborations today. First, Merck is buying Austria-based Themis, a vaccines and immune-modulation therapies company focused on infectious diseases and cancer. Merck hasn’t disclosed financial details, except that it is a cash deal to buy all outstanding Themis shares.

Themis has a pipeline of vaccine candidates and immune-modulatory therapies that it has built using its measles virus vector platform. The vector was originally developed by researchers at the Institut Pasteur and licensed exclusively to Themis for specific viral indications. In March, the company joined a consortium with the Institut Pasteur and The Center for Vaccine Research at the University of Pittsburgh, which is supported by monies from the Coalition for Epidemic Preparedness Innovations (CEPI), to develop a vaccine candidate against COVID-19. “Building on the pioneering work of the Institute Pasteur, the Themis team has established specialized expertise that complements Merck’s own capabilities in the discovery, development, manufacturing and global distribution of vaccines,” said Roger M. Perlmutter, president, Merck Research Laboratories. “We are eager to combine our strengths both to develop an effective COVID-19 vaccine in the near term and to build a pandemic preparedness capability directed toward emerging agents that pose a future epidemic threat.”

Secondly, Merck is collaborating with IAVI, a nonprofit scientific research organization focused on global health challenges. They are partnering to develop a vaccine against COVID-19. The vaccine candidate uses the recombinant vesicular stomatitis virus (rVSV) technology that was used for Merck’s Ebola Zaire virus vaccine, ERVEBO. Merck has also entered an agreement with the Biomedical Advanced Research and Development Authority (BARDA), part of the office of the Assistant Secretary for Preparedness and Response within the U.S. Department of Health and Human Services (HSS)....