Pfizer Claims 90% Efficacy of its Antiviral Pill for Covid Treatment
Manas Dasgupta
NEW DELHI, Nov 5: After the United Kingdom approved an antiviral pill manufactured by Merck for the treatment Covid-19, its competition Pfizer Inc. on Friday claimed that its experimental antiviral pill for the infectious disease cut rates of hospitalization and death by nearly 90% in high-risk adults.
The Pfizer joined the race with others to bring the first easy to use medicine for Coronavirus treatment which currently is only depended on prevention through vaccination.
Currently all COVID-19 treatments used in the U.S. require an IV or injection. Competitor Merck’s COVID-19 pill is already under review at the Food and Drug Administration after showing strong initial results. The UK on Thursday became the first country to OK it.
Pfizer said it would ask the FDA and international regulators to authorize its pill as soon as possible, after independent experts recommended halting the company’s study based on the strength of its results. Once Pfizer applies, the FDA could make a decision within weeks or months. If authorized the company is likely to sell the drug under the brand name Paxlovid.
Researchers worldwide have been competing with each other to find a pill against COVID-19 that can be taken at home to ease symptoms, speed recovery and reduce the crushing burden on hospitals and doctors.
Pfizer released preliminary results Friday of its study of 775 adults. Patients who received the company’s drug along with another antiviral shortly after showing COVID-19 symptoms had an 89% reduction in their combined rate of hospitalization or death after a month, compared to patients taking a dummy pill. Fewer than 1% of patients taking the drug needed to be hospitalized and no one died. In the comparison group, 7% were hospitalized and there were seven deaths.
“We were hoping that we had something extraordinary, but it’s rare that you see great drugs come through with almost 90% efficacy and 100% protection for death,” said Dr. Mikael Dolsten, Pfizer’s chief scientific officer.
Study participants were unvaccinated, with mild-to-moderate COVID-19, and were considered high risk for hospitalization due to health problems like obesity, diabetes or heart disease. Treatment began within three to five days of initial symptoms, and lasted for five days. Patients who received the drug earlier showed slightly better results, underscoring the need for speedy testing and treatment.
Pfizer reported few details on side effects but said rates of problems were similar between the groups at about 20%.
An independent group of medical experts monitoring the trial recommended stopping it early, standard procedure when interim results show such a clear benefit. The data have not yet been published for outside review, the normal process for vetting new medical research.
Top U.S. health officials continue to stress that vaccination would remain the best way to protect against infection. But with tens of millions of adults still unvaccinated — and many more globally — effective, easy-to-use treatments would be critical to curbing future waves of infections.
The FDA has set a public meeting later this month to review Merck’s pill, known as Molnupiravir. The company reported in September that its drug cut rates of hospitalization and death by 50%. Experts warn against comparing preliminary results because of differences in studies.
Although Merck’s pill is further along in the U.S. regulatory process, Pfizer’s drug could benefit from a safety profile that is more familiar to regulators with fewer red flags. While pregnant women were excluded from the Merck trial due to a potential risk of birth defects, Pfizer’s drug did not have any similar restrictions. The Merck drug works by interfering with the coronavirus’ genetic code, a novel approach to disrupting the virus.
Pfizer’s drug is part of a decades-old family of antiviral drugs known as protease inhibitors, which revolutionized the treatment of HIV and hepatitis C. The drugs block a key enzyme which viruses need to multiply in the human body. The drug was first identified during the SARS outbreak originating in Asia during 2003. Last year, company researchers decided to revive the medication and study it for COVID-19, given the similarities between the two coronaviruses.
The U.S. has approved one other antiviral drug for COVID-19 Remdesivir and authorized three antibody therapies that help the immune system fight the virus. But they have to be given by IV or injection at hospitals or clinics, and limited supplies were strained by the last surge of the delta variant.
A trial of Pfizer Inc’s experimental antiviral pill was stopped early after the drug was shown to cut by 89% the chances of hospitalization or death for adults at risk of developing severe disease, the company said on Friday.
The results appear to surpass those seen with Merck & Co Inc’s pill, Molnupiravir which was shown last month to halve the likelihood of dying or being hospitalized for COVID-19 patients also at high risk of serious illness.
Full trial data is not yet available from either company. Pfizer said it planned to submit interim trial results for its pill, which is given in combination with an older antiviral called ritonavir, to the U.S. Food and Drug Administration as part of the emergency use application it opened in October. The combination treatment will consists of three pills given twice daily.
The planned analysis of 1,219 patients in Pfizer’s study looked at hospitalizations or deaths among people diagnosed with mild to moderate COVID-19 with at least one risk factor for developing severe disease such as obesity or older age. It found that 0.8% of those given Pfizer’s drug within three days of symptom onset were hospitalized and none had died by 28 days after treatment.
Merck tested its drug within five days of symptom onset. “We saw that we did have high efficacy, even if it was five days after a patient has been treated … people might wait a couple of days before getting a test or something, and this means that we have time to treat people and really provide a benefit from a public health perspective,” Annaliesa Anderson, head of the Pfizer program, said.
The company did not detail side effects of the treatment, but said adverse events happened in about 20% of both treatment and placebo patients. “These data suggest that our oral antiviral candidate, if approved 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,” Pfizer Chief Executive Albert Bourla said in a statement.
Pfizer said it was currently expecting to produce more than 180,000 packs by the end of 2021 and at least 50 million packs by the end of 2022, of which 21 million would be produced in the first half. “We are currently bringing on additional capacity and ramping up further and we look forward to updating these numbers in the coming weeks,” the company said.
