Corona Daily 195: Vaccines vs Drugs

In the last few months, we have been bombarded with news about Covid-19 vaccines; little has been said about Covid-19 drugs. As if protecting healthy people from Covid-19 is far more important than treating people ill with Covid-19. In the weekend edition, Carl Zimmer, a NYT columnist, discusses the reasons for this imbalance.

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The US Government invested $18.5 billion into vaccines, producing five effective vaccines at record speed. Investment in drugs was less than half at $8.2 billion, and lopsided. Too much money spent on few candidates such as monoclonal antibodies. Antivirals are drugs that can stop the disease early. But their trials could not happen for want of funds or enough patients.

Trump did much damage by being brand ambassador for hydroxychloroquine and chloroquine. All evidence pointed out these malaria drugs don’t work against Covid. Yet, there are still 179 clinical trials with 170,000 patients carried on.  US federal government spent a few million dollars infusing convalescent plasma into some 100,000 covid patients. In January, the trials showed it didn’t work for hospitalized patients.

Hydroxychloroquine story showed science and politics should not be mixed.

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Dexamethasone, a steroid drug, has been successful in reducing mortality of the severely ill patients.

Medicines need to be tested in large trials just as vaccines, with half the groups given placebos. Getting thousands of patients to take part in these trials is a logistical challenge. Patients generally visit hospitals for treatment, and not to be guinea pigs for unproven drugs. At the beginning of the pandemic the focus was on two drugs: Remdesivir, which stops viruses from replicating inside cells. This drug could shorten the recovery time, but had no effect on mortality. Monoclonal antibodies stop the virus from entering cells. Powerful, but only if given before patients are sick enough to be hospitalized.

Some researchers and doctors went for trial and error, on their own. Doctors at French psychiatric hospitals noticed that few patients became ill with covid as compared to their caretakers. It was speculated Chloropromazine, an antipsychotic drug, may be the reason. In the lab, it prevented the virus from multiplying. Enthusiastically, the doctors decided to start a trial, but the pandemic subsided at that time. Trials couldn’t happen in France or the USA because they ran out of patients.

Scientists believe the best time for a drug trial is at the beginning of the infection. But it is very hard to recruit trial volunteers at that stage. Participants who have just tested positive must be contacted, their consent obtained, and drugs given to them.

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Drug development sometimes takes ten to fifteen years. Dr Sumit Chanda, a Californian virologist, and his team screened a library of 13000 drugs, mixing each of them with cells and coronaviruses to see if infections could be stopped. A cheap leprosy pill Clofazimine fought of the virus in hamsters and other animals. Now Dr Chanda is hoping some pharma company or Joe Biden can sponsor a large clinical trial.

Pharma companies have started funding some trials of repurposed drugs. Plitidepsin, a 24-year-old cancer drug, was 27 times more potent than remdesivir at halting the coronavirus, in lab conditions. A large trial is planned in Spain.

Merck is running a trial for Molnupiravir, originally meant for influenza. It has been effective in curing ferrets of covid-19. In March, the results will show if it can cure human beings. This is a particularly interesting drug because for infected mice, it could treat all coronaviruses, including SARS and MERS.

“The efforts are unlikely to provide therapeutics in 2021,” said Dr Francis Collins, the head of the National Institutes of Health. “If there is Covid-24 or Covid-30 coming, we want to be prepared.”

Ravi