06/11/2021
Covid Update
*Paxlovid®️ new anti viral combination pill from Pfizer*
New drug combo has shown to cut the chances of hospitalization or death for adults at risk of developing severe disease by 89%.
The trial of Pfizer Inc's experimental antiviral pill for Covid-19 was stopped early once it showed robust benefits.
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.
New Drug a protease inhibitor is given in combination with an older antiviral called ritonavir. *The combination treatment, which will have the brand name Paxlovid, consists of three pills given twice daily*.
(The combination is different from Lopinavir+ Ritonavir which failed in Solidarity trials in 2020)
Pfizer's drug, part of a class known as protease inhibitors, blocks an enzyme the coronavirus needs in order to multiply. So it stops multiplication of Virus.
Pfizer plans to submit trial results to the US food and drug administration as part of the emergency use application it opened in October.
*Trial was done in 1,219 patients*. 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. But company didn't clarify if it works the same way in patients with multiple co-morbidities like Diabetes and Obesity
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. That compared with a hospitalization rate of 7% for placebo patients. There were also seven deaths in the placebo group.
Rates were similar for patients treated within five days of symptoms - 1% of the treatment group was hospitalized, compared with 6.7% for the placebo group, which included 10 deaths.
*Drug is effective only if given early.*
Antivirals need to be given as early as possible, before an infection takes hold, in order to be most effective. Merck tested its drug within five days of symptom onset.
Once the virus takes hold, the inflammatory effects drive the course of disease and then only anti-inflammatory drugs like corticosteroids work.
In SARS too, Oseltamivir works only if given early in course of infection.
Works even after Five days
Combo has high efficacy, even if it was five days after a patient has been infected was treated, as 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.
*Side effects*
The company did not detail side effects of the treatment, but said adverse events happened in about 20% of both treatment and placebo patients.
*Comparison with Molnupiravir*
1.Merck's molnupiravir has a different mechanism of action designed to introduce errors into the genetic code of the virus.
2 It had shown 50% efficacy in reducing death or hospitalization when given early in high risk individuals.
3Merck has already sold millions of courses of the treatment, which was approved this week by UK regulators, to the United States, the UK and others.
4. MSN Pharma and Aurobindo Pharma has withdrawn from trial of Molnupiravir in moderately ill patients
5. While Pfizer trial was closed early for the robust benefits show. It seems more to do with trial design than affectivity of drug in moderately sick patients
Britain also has secured 250,000 courses of Pfizer's antiviral.
*Yet to be seen if needed in mild disease?*
Pfizer is also studying whether its pill could be used by people without risk factors for serious Covid-19 as well as to prevent coronavirus infection in people exposed to the virus.
Dr. Abdul Qadir
MBBS, MS
Advanced Laparoscopic Surgeon
Samra Hospital
