The Paxlovid remains difficult to access

The number of patients who can receive Paxlovid if they test positive for COVID-19 was expanded Thursday by Quebec’s Ministry of Health and Social Services. But its access remains very limited: between the moment the disease is detected and the moment treatment is approved for a patient, it is often too late.

Mathieu Perreault
The Press

The problem? 40 to 50 molecules – over-the-counter drugs and supplements – are likely to interact with Paxlovid and prevent it from being prescribed to treat COVID-19, says Makeda Semret, director of the Center’s Antibiotic Stewardship Program. McGill University Health Center (MUHC). However, the evaluation by a pharmacist of the file of each potential patient takes time, while Paxlovid reduces the risk of hospitalization by more than 89% if taken within the first five days after the onset of symptoms, according to a trial conducted by Pfizer with non-vaccinated people.

Some patients were unable to have Paxlovid because more than five days had passed from the onset of symptoms when the pharmacist gave the go-ahead, according to Dr.^D Semret.

“You need an assessment by a pharmacist who is familiar with Paxlovid. In some cases, treatment with another drug must be interrupted, in others, the dose of the drug with which there is an interaction can simply be lowered. But for some patients, an interruption or dose reduction is not possible. »

Paxlovid was cleared in the United States in late December and in Canada in mid-January. Due to limited supplies, Quebec initially reserved it for immunosuppressed patients and patients who were not adequately vaccinated with risk factors. On Thursday, adequately vaccinated patients with certain risk factors were added to the population with access to Paxlovid.

Monoclonal antibodies are often preferred over Paxlovid because their efficacy is almost as good, according to Dr.^D Semret, and that they don’t have the same drug interaction problem. Paxlovid is taken in pill form, at home. It is delivered to the patient by one of the 65 pharmacies designated by the provincial Ministry of Health as a distribution point. Monoclonal antibodies are also given in the days following the appearance of symptoms of COVID-19, by intravenous transfusion.

Patients eligible for monoclonal antibodies and Paxlovid are the same. Of note, many monoclonal antibodies previously effective against COVID-19 are not effective against the Omicron variant.

Facilitate decision making

Having the family doctor take over the drug interaction assessment would be “an ideal situation,” according to infectious disease specialist Andrew Morris of the University of Toronto, who is one of the leaders of the Ontario drug distribution committee. Paxlovid and monoclonal antibodies. “They could do it in advance, to act quickly if there is a positive test for COVID-19. At the same time, we must avoid using Paxlovid for patients who do not need it. Before COVID-19, I was an antibiotic resistance specialist. So I’m worried that resistance to this antiviral is emerging. »

Benoît Morin, president of the Quebec Association of Proprietary Pharmacists (AQPP), thinks that family doctors could call the pharmacist of their patients at risk to see what the drug interactions with Paxlovid are.

In this way, in the event of a positive test, they would know immediately whether to go for Paxlovid or monoclonal antibodies.

This is already the case in the United States, notes the D^r Raymund Razonable, of the famous Mayo Clinic in Minnesota, although the situation varies from state to state. The D^r Razonable has just published a study confirming the validity of a tool to know who can have access to monoclonal antibodies. This FDA tool, called MASS, consists of a score for different risk factors. In the event of a drug shortage, the minimum threshold for receiving antivirals or monoclonal antibodies is raised, explains Dr.^r Razonable.

The MUHC’s Antibiotic Stewardship Program has posted a “decision tree” online that shows which treatments for COVID-19 are appropriate, and which is attracting a lot of interest from other hospitals, according to Dr.^D Semret. About 30 doctors from outside the MUHC call the Antibiotic Stewardship Program number every day to find out if their patients are eligible for Paxlovid or monoclonal antibodies. “In two out of three cases, these are patients who have not yet tested positive,” says Dr.^D Semret.

Quebec received 6,300 Paxlovid treatments in January and is expected to receive 6,200 in February and 19,000 in March.