New Covid-19 treatments bolster medicine’s fight against the pandemic | USA
Pharmaceutical companies have raced to produce drugs and vaccines to fight the coronavirus pandemic, but until recently only vaccines have been successful in protecting large numbers of people. In the summer of 2020, hopes were pinned on drugs like hydroxychloroquine, until studies finally found it to be largely ineffective against the disease, then remdesivir, which could only reduce hospital stays for some patients from 15 to 11 days.
Vaccines have since achieved great success where they have been widely used as developed countries embarked on their largest vaccination campaigns in history to protect civilians. Hundreds of thousands of lives have been saved, but the limitations are clear: poor countries have received few doses and even in rich countries large segments of the population reject vaccines. In immunocompromised patients, vaccines cannot elicit the desired immune response.
As the world prepares for the end of the second year of the pandemic, the spotlight is once again on medication as an alternative to fighting Covid-19. Two antivirals, made by pharmaceutical giants Pfizer and Merck (which operate outside the US and Canada as Merck Sharp and Dohme or MSD), are now on the market. Both are touted as easy to administer and effective in fighting the disease.
“The fact that the drugs Pfizer and MSD are administered orally is a substantial innovation because it makes them much easier to use. They slow the progression of the disease in the beginning, when the patient is not yet in a serious condition, and this usually happens outside a hospital setting,” explains Juan Pablo Horcajada, head of the infectious diseases department at the Hospital Del Mar in Barcelona, and general coordinator Covid-19 in the hospital.
Pfizer has announced that its antiviral drug, marketed under the brand name Paxlovid, will reduce hospitalizations and deaths by 89%, according to its own data. The course of treatment consists of 30 pills to be taken over five days. Ten of these pills contain ritonavir, an ancient antiviral drug once used for HIV. The European Medicines Agency (EMA) announced on November 19 that it has begun analyzing Pfizer’s data with the aim of “starting this assessment to support national authorities that can decide on its early use for Covid-19, for example in emergency settings, prior to authorization for the put it on the market.” The treatment is now awaiting final approval.
The EMA also advised on the use of molnupiravir (marketed as Lagevrio), another antiviral drug co-developed by MSD with Ridgeback Biotherapeutics. That treatment consists of 40 pills to be taken in five days, and the number of cases has been halved hospitalization required and deaths, according to data from both companies.
They slow the progression of the disease initially, when the patient is not yet in a serious condition, and this is usually done outside of a hospital setting
Juan Pablo Horcajada, Hospital del Mar, Barcelona
“These two drugs are coming to fill an important niche, because we had nothing until now. There are patients diagnosed in primary care who do not meet the criteria for hospitalization, but who are at risk of the disease subsequently progressing to very serious forms and even death. It was very frustrating for us,” explains Santiago Moreno, head of infectious diseases at Ramón y Cajal Hospital in Madrid. Experts believe that oral administration will help these treatments reach more people faster, as the first five days of symptoms are key. In this way, the two new treatments have a great advantage over other recently developed drugs.
Another category of treatment known as monoclonal antibodies has also shown some success. One is Evusheld from AstraZeneca, which the drug company claims has an efficacy rate of 88%, and which the EMA has been evaluating since October 14. The other is Ronapreve, developed by Regeneron and Roche, which has already received EMA authorization and is helping to treat patients who are already hospitalized in a serious condition and who lack their own defence against the coronavirus. “These antibodies are proteins that are artificially designed to attack a very specific part of the virus and nothing else, making them extremely safe and also effective,” Horcajada says.
Jesús Sierra, a spokesperson for the Spanish Association of Hospital Pharmacy, points out that monoclonal antibodies “are also very important and effective when applied in the first five days, but they have two caveats.” The first is that they must be given intravenously in the hospital, and second that “they are drugs that replace the antibodies a vaccinated person has. Therefore, they were tested in the unvaccinated population older than 50 years. And this population is very small in Spain.”
In total, the EMA has approved, is evaluating or has informed Member States of more than a dozen treatments for the coronavirus. In addition to antivirals and monoclonal antibodies, there are immunosuppressants such as dexamethasone or tocilizumab. “What these drugs do is curb the body’s immune response when it’s excessive. From some point, between the fifth and seventh day of infection, the problem that endangers the patient’s life is the excessive response of their immune system, and these drugs are trying to stop that,” explains Horcajada.
The United States has already signed deals with Pfizer and Merck to purchase millions of these new treatments for its citizens, in behavior reminiscent of the Donald Trump administration’s hoarding of remdesivir. The US has now purchased 10 million courses of Paxlovid from Pfizer, at a price tag of $5.3 billion (€4.7 billion), and an additional 3.1 million courses from Merck’s Lagevrio for about $2.2 billion (€ 2 billion).
The final stages of development of both drugs have been accompanied by unprecedented announcements from the pharmaceutical giants. Merck said in October it will manufacture its new drug as a generic in the world’s 105 lowest-income countries, and Pfizer made the same announcement last week for its antiviral drug. None of the major vaccines currently on the market are allowed to be manufactured as generic drugs.