Pfizer making its experimental COVID-19 antiviral pills inside a laboratory in Freiburg, Germany on Nov. 16, 2021.Supplied/AFP/Getty Images
The COVID-19 drugs have finally arrived – almost.
For the first time, people infected with coronavirus may soon be able take a pill (or 40) to reduce their risk of hospitalization and death.
Is this a pandemic game-changer?
The jury is still out on that question, and it will be for a while.
At the very least, it’s another positive development (along with the arrival of pediatric vaccines) at a time when we need it, as vaccine protection wanes and COVID-19 cases start to climb anew.
In recent weeks, two pharma giants have asked for regulatory approval for oral antivirals in the U.S., and they will likely also do so in Canada in the near future.
The most promising is from Pfizer, a company that already has a successful COVID-19 vaccine.
In a clinical trial, its antiviral pill, known by the brand name Paxlovid, reduced hospitalization up to 89 per cent in high-risk patients suffering from mild or moderate COVID-19 infections.
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Earlier, another pharmaceutical company, Merck, got the pandemic-ravaged world excited with its oral antiviral Molnupiravir, which reduced the risk of hospitalization by 50 per cent in a similar population of high-risk patients.
Those are impressive numbers, but they come with many provisos.
The first important note is that the data we have is limited and comes from the companies themselves, without any independent review. We should always be leery of science by press release.
We should also be cautious about relative risk reductions, because they overstate effectiveness.
Take Pfizer’s Paxlovid study. What does an 89 per cent reduction actually mean? Well, three of 389 patients in the study who took the drug required hospitalization, compared with 27 of 385 patients who received a placebo.
The story is similar with Merck’s Molnupiravir study: 28 of 385 patients who received treatment with the antiviral ended up in hospital, compared with 53 of 377 who received sugar pills.
In other words, a very small number of patients with mild to moderate COVID-19 actually end up in hospital, but that number can be reduced.
Clearly, these drugs are not silver bullets, even if they have more benefit than much-hyped ivermectin.
Still, the idea that patients with not-too-serious symptoms of COVID-19 could pick up a drug at the pharmacy and treat themselves at home is a step forward.
The antivirals we have now, such as remdesivir, require intravenous infusion, meaning that they have to be administered in hospital. So too do monoclonal antibodies (which are not antivirals).
The other real-world concern about the new oral antivirals is that they have to be taken in a timely fashion – ideally within 3-5 days of onset of symptoms.
This poses a number of problems.
If you’re going to be treated within three days, you first need a COVID test, and then you need to get medical care.
Studies show that fewer than half of people who are infected with COVID-19 seek treatment promptly.
Getting results from a PCR test can take a few days, and Canada makes little use of rapid tests, which are also slightly less precise.
Further, our overburdened health system doesn’t really have the capacity to see patients with mild to moderate symptoms, let alone promptly.
The treatments themselves are no picnic – 30 pills (Paxlovid) or 40 pills (Molnupiravir) over five days.
Then there is the cost, roughly US$700 for a course of treatment. That’s not cheap – but it is a lot less than even a single day of hospitalization, so it could be a good investment if the drugs perform as advertised in small clinical trials. (While the U.S. has committed to ensuring the treatments “will be easily accessible and free,” according to President Joe Biden, it’s not yet clear if these drugs would be provided at no charge in Canada, given that most prescription medications are not.)
The good-news aspect of this story is that both Pfizer and Merck have agreed to license their products to the Medicines Patent Pool so generic versions can be produced and sold cheaply in low-income countries – in stark contrast to what we’ve seen with vaccines.
The downside is that, like vaccines, wealthy countries are gobbling up production capacity. The U.S. alone has already committed to purchasing 10 million courses of treatment of Paxlovid from Pfizer (US$5-billion), and 3.3 million courses of treatment of Molnupiravir from Merck (US$2.2-billion). Canada will no doubt also get in on the buying spree soon.
These purchases speak to the desperate desire for simple treatments – but we can’t forget that prevention always trumps treatment.
Post-infection drugs that lessen hospital admissions are not a substitute for COVID-19 vaccinations that help prevent infections, but they are a welcome addition to the pandemic toolbox.
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