All You Need To Know About Pfizer's Anti-Covid Pill

The American pharmaceutical company Pfizer, which developed the mRNA vaccine against novel coronavirus along with its German partner BioNTech, has begun giving people doses of a pill against Covid-19 as part of the clinical trial. In a large Phase 2/3 trial exploring the novel oral therapy to relieve Covid-19 symptoms, the participants have been dosed, and the initial results are expected to be available before the end of the year.

Perhaps the most important missing link in the fight against SARS-CoV-2 is a simple, pill-based treatment that can be administered at home during the early stages of illness. In the last 18 months, a staggering number of medicines have been created, including prophylactic vaccines and monoclonal antibodies to prevent severe disease.

While Covid-19 vaccines can help reduce an individual's risk of hospitalisation or even death and various medicines can be given while the patient is in the hospital to prevent deterioration of the health, an effective oral medication that can be taken at home in the early stages of the infection is also necessary.

As there are some anti-Covid oral drugs are currently under development, Pfizer's product—called PF-07321332—is one of the first oral antivirals designed particularly to target SARS-CoV-2 to reach advanced human trial phases. It belongs to the protease inhibitor class of antiviral drugs. Proteases—which are enzymes that are essential for viral replication mechanisms—have been developed to treat HIV/AIDS, as well as hepatitis C.

In the latest statement about the clinical study, Pfizer stated that "the randomised, double-blind trial" will include around 1,140 participants, who will receive PF07321332/ Ritonavir or placebo orally every 12 hours for five days. The American company also said: "Protease inhibitors, like PF-07321332, are designed to block the activity of the main protease enzyme that the coronavirus needs to replicate."

It explained that "Co-administration with a low dose of ritonavir is expected to help slow the metabolism, or breakdown, of PF-07321332 in order for it to remain in the body for longer periods of time at higher concentrations, thereby working continuously to help combat the virus. Ritonavir has previously been used in combination with other antivirals to similarly inhibit metabolism."

Pfizer began the first trial in July to see if a course of the medicine given to people at high risk of severe Covid-19 would lower hospitalisation and death rates. The second study was conducted in August, during which researchers investigated the effects of the medication on individuals at low risk of severe Covid-19. The motive behind the studies is to find out whether this drug can shorten the duration, as well as the severity of coronavirus infection symptoms in healthy people.

As claimed by Pfizer, the phase 2/3 study "is part of a global clinical development program, consisting of multiple ongoing and planned clinical trials to evaluate this early-intervention, outpatient therapeutic candidate for potential use in a broad population of patients".

The company noted that if the clinical trials find success, "PF-07321332/ritonavir has the potential to address a significant unmet medical need", while providing people with an oral therapy that "could be prescribed at the first sign of infection", reducing the need to be hospitalised after contracting the novel virus.

Meanwhile, German company Merck and the American biotechnology firm Ridgeback Biotherapeutics have started a Phase 3 MOVe-AHEAD clinical trial for molnupiravir, an oral medication that prevents Covid-19. It was said that nearly 1,332 adult participants would be enrolled in the study if they live in the same house as symptomatic Covid-19 patients.

In the case of anti-Covid drugs, the Indian regulators, the Drug Controller General of India (DCGI) has approved an Emergency Use Authorization (EUA) for the generic version of Tocilizumab in the country for the treatment of Covid-19 in hospitalised patients. This drug is designed to help those who are on systemic corticosteroids and need supplemental oxygen, mechanical ventilation (non-invasive or invasive), or extracorporeal membrane oxygenation (ECMO).

Dr B Partha Saradhi Reddy, chairman of the Hyderabad-based Hetero Group—whose biologics arm Hetero Biopharma will be manufacturing the drug—said: "This demonstrates our technical capabilities and commitment to bringing important therapeutics relevant to Covid care. We will be working closely with the government to ensure equitable distribution."

Additionally, after collaborating with the Defence Research and Development Organisation (DRDO) in India, the pharmaceutical company Bajaj Healthcare has announced the launch of the Active Pharmaceutical Ingredient (API) and formulation of 2-Deoxy-D-Glucose (2-DG), which is an antiviral medicine used to treat Covid-19 patients, under the trade name DGJAJ.

Anil Jain, joint managing director of Bajaj Healthcare said: "Health experts are anticipating a third wave of Covid-19 [in India], which may be even more severe as the virus has undergone several mutations over time. We hope the availability of an effective treatment such as 2-Deoxy-D-Glucose (2-DG) will offer patients with much needed and timely therapy option."