I forgot to post this article 30 days after it appeared in the Wall Street Journal. Thanks to Brian Schwartz for reminding me.

Congress’s mandate that medications be proved effective is unnecessary and delays potential cures.

By Charles L. Hooper and David R. Henderson

March 25, 2020 6:28 pm ET

The federal government requires pharmaceutical companies to prove that their drugs are both safe and effective before putting them on the market. Before 1962, companies needed to prove only safety. While there is some appeal to this two-hurdle approach, evidence suggests that there is only a slight benefit and a tremendous cost. With the Covid-19 pandemic sweeping the world, there has never been a better time to revoke the Food and Drug Administration’s efficacy requirement.

The thinking behind the FDA’s two-hurdle approach is that ineffective drugs cost money and impose an opportunity cost: While the ineffective drug is being used, potentially effective ones are not. But researchers who have studied the 1962 law, known as the Kefauver-Harris Amendments, have concluded that before it was enacted, ineffective drugs were a small percentage of the market and therefore not much of a problem.

Further, the Kefauver-Harris Amendments dramatically increased the time and cost of getting new drugs approved. Evidence provided by University of Chicago economist Sam Peltzman suggests that the number of new drugs approved dropped by 60% in the decade following the law change. We have fewer ineffective drugs, but also far fewer effective ones than we could have had.

That’s not all that’s wrong with the Kefauver-Harris Amendments.

Before 1962, patients and doctors needed to try drugs to see if they worked for a particular patient at a particular time. It’s called trial and error and, despite the change in law, is still the standard medical approach.

To understand how little the FDA’s two-hurdle approach contributes, consider Merck’s Keytruda (pembrolizumab), which has recently become one of the hottest drugs on the market. Keytruda got some good press after Jimmy Carter, who was suffering from melanoma, was diagnosed as cancer-free after taking it. Mr. Carter was lucky because in one clinical trial Keytruda destroyed or reduced the tumors in only 34% of patients. Keytruda—which was the fourth biggest-selling drug globally in 2018 and brought in worldwide revenues of $11.1 billion last year—is far from a sure thing.

Does the FDA, which approved Keytruda as safe and effective for melanoma, know which patients will benefit from it? No. The potential benefits described on the drug’s label are what happened to strangers in another time and place. Patients still have to try Keytruda to know if it will help them. An FDA approval for efficacy is largely duplicative.

Enter Covid-19, the disease caused by the new coronavirus, SARS-CoV-2. There are no proven therapies to treat an infection of that virus. One of the most promising candidates is Gilead Sciences ’ remdesivir, which has shown some potential in treating other coronaviruses, such as SARS and MERS. Due to its use in treating Ebola infections, remdesivir is known to be generally safe.

With the FDA’s two-hurdle requirement in place, however, remdesivir must be proven effective in clinical trials before it can be sold for widespread use in Covid-19. These clinical trials take time, and they still won’t answer many of the questions doctors have about the drug’s use against Covid-19 now. What’s the right dose to get remdesivir into the lungs? How early should it be given? If it is given to sick patients already on ventilators in hospitals, will it help? All these things will depend on the individual patient.

And then, even if remdesivir is approved by the FDA, patients and doctors will still resort to trial and error, because the success rate won’t be 100%.

Instead, the FDA should allow patients and doctors to try remdesivir today. We know it’s safe, and there are no other proven therapies. With more widespread usage, the medical community will have a tool to fight back against Covid-19. Controlled clinical trials can continue largely as they normally would. Though access to an experimental therapy won’t be an incentive to join a clinical trial, many others remain—such as excellent free care and a sense of pride in helping society and other patients. This two-pronged approach would not only potentially save thousands of lives but also provide much more information.

If you were diagnosed with Covid-19 today, would you choose to take nothing? Or would you want a safe drug that has shown some potential against the virus? We suspect the great majority of Covid-19 patients would choose the latter option. And they would get it today, not months from now, when it would be of no use to them.

This same process plays out every day with other conditions that can be more dangerous than Covid-19. While patients and doctors continue to resort to trial and error out of necessity, the government insists that they initiate their experiments only after the FDA has completed its. This is a critically flawed approach to medicine.

Even as the pandemic robs Americans of their jobs, health and lives, it could reward us with a silver lining if we use the opportunity to take a hard look at our drug-approval process. Revoke the FDA’s drug-efficacy requirement.

Mr. Hooper is president of Objective Insights Inc., a company that consults for life-science companies. Mr. Henderson, a research fellow with the Hoover Institution, was senior health economist with President Reagan’s Council of Economic Advisers.