All Eyes On Gilead
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All Eyes On Gilead
Emergency approval of the antiviral drug remdesivir is the first good news of this pandemic. Gilead Sciences was ready
By Robert Langreth

LAST NEW YEAR’S EVE, TOMAS CIHLAR, VICE PRESIDENT for discovery virology at Gilead Sciences Inc., received a disturbing email from a top infectious diseases expert at the University of Virginia. The researcher had been working with Cihlar on a plan to test the Gilead drug remdesivir as a treatment for Middle East respiratory syndrome, a deadly disease caused by a coronavirus. MERS had been flaring up from time to time in Saudi Arabia and elsewhere since 2012, but this email was about something more ominous. There were cases of pneumonia suddenly emerging in Wuhan, China. Watch this one, the virologist warned. It might be a new coronavirus.

Remdesivir was one of the few experimental medicines that had shown promise in lab studies against a wide variety of coronaviruses. Like the rest of the world, Gilead knew next to nothing about this new one. The World Health Organization hadn’t yet confirmed there was sustained human-to-human spread, and the extent of the outbreak in Wuhan wouldn’t become clear for weeks. Nobody knew at that point whether it would become a pandemic, but Gilead started planning on the assumption it could. Within weeks, Chief Executive Officer Daniel O’Day formed a task force to study how to test remdesivir and, if it worked, mass-produce it.

Even by the exacting standards of pharmaceuticals, remdesivir is tricky to produce—the monthslong process involves 70 raw materials, reagents, and catalysts. The resulting active pharmaceutical ingredient, or API, is a white powder, 1.1 grams of which constitutes a single 10-day course of treatment. Remdesivir is administered intravenously, which introduces additional complexity into the manufacturing: The powder must be dissolved into a solution and then placed into glass vials under sterile conditions.

Thanks to its work on Ebola, Gilead already had a small supply of remdesivir on hand. Sitting in cold storage in Switzerland and California were enough 30-milliliter vials of the drug to treat 5,000 people, which made it possible to begin human trials in the U.S., China, and elsewhere. In a factory in Edmonton, Alb., Gilead also had 100 kilograms of the bulk powder, perhaps enough to treat 90,000 patients.

To fill enough remdesivir vials to treat millions in a pandemic, however, would require a metric ton or more of the bulk drug. Gilead didn’t have close to that—and still doesn’t. So back in January it ordered more than a dozen of the most crucial starting materials and reagents from suppliers in China, Europe, and elsewhere. Gilead also helped its contractors locate sufficient supplies of compounds needed to make those starting materials.

There haven’t been a lot of stories of foresight and preparedness in this pandemic. This is one. After a big trial sponsored by the National Institute of Allergy and Infectious Diseases, remdesivir was authorized on May 1 for emergency use on Covid-19, the disease caused by the new coronavirus. Anthony Fauci, the director of the NIAID, has likened the trial of remdesivir to the first big trial of AZT, the first drug for HIV. As AZT was, remdesivir is being authorized for wide use before it’s fully clear how effective it will be. Preliminary data from the 1,060-person trial show the medicine sped recovery in the most serious cases of Covid-19 by about four days. Full details haven’t been published, and a smaller trial in China didn’t find a benefit. The Food and Drug Administration, in granting the emergency authorization, didn’t allow Gilead to claim the drug is safe and effective for Covid-19; the agency said only that it’s reasonable to believe the medicine may help.

“It is not a cure,” O’Day says. “It is a first step, but it is an important first step.” Many additional drugs and vaccines will probably be needed to stop the pandemic, he says. Gilead itself is working on an easier-to-administer inhaled form of remdesivir that might be useful for less severe cases.

But with few other medicines available and the number of Covid-19 cases continuing to grow steadily—about 4.3 million cases and 294,000 deaths at press time—the drug is likely to be in high demand until a better treatment or a vaccine is available. Gilead plans to donate the first 1.5 million vials, enough for roughly 200,000 patients. (The number depends on the dosage: The emergency use authorization allows both a 10-day course of treatment for patients on ventilators and a 5-day course for those not on ventilators.) Those will be delivered this spring. By the fall a much larger supply should start to become available, and Gilead is also working with other companies to bring new factories online overseas. The question is, can Gilead make enough of it for the whole world?

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May 18, 2020