Startup Pardes Biosciences joins hunt for Covid-19 pill

U.S. regulators have approved the drug remdesivir, made by Gilead Sciences Inc., for hospitalized patients, and monoclonal antibodies taken intravenously have gained emergency-use authorizations to treat patients at high risk for developing severe Covid-19 and to prevent hospitalizations.

Carlsbad, Calif.-based Pardes, which plans to go public by October through a merger with a blank-check company, is vying with drugmakers such as Pfizer Inc. and Shionogi & Co. to create a medicine patients could take easily outside the hospital. Companies are launching studies of these medicines, called protease inhibitors, as Covid-19 cases have been rising, especially among the unvaccinated.

These companies are betting that drugs will be needed to complement vaccines because of breakthrough infections among the vaccinated and because many people are hesitant to get vaccinated.

“It’s really clear that we need more than vaccines to fight this pandemic," said Jim Tananbaum, chief executive of Foresite Capital, an investor in Pardes.

Protease inhibitors, introduced in the 1990s, are now used to treat viral diseases including HIV, said Aaron Glatt, chair of the Department of Medicine at Mount Sinai South Nassau on Long Island. Protease inhibitors block an enzyme the virus needs to replicate.

Protease inhibitors for Covid-19 are an exciting prospect, but still must be proved safe and effective, said Dr. Glatt, also a spokesman for the Infectious Diseases Society of America. He added that there is always potential for unforeseen side effects to emerge as research progresses.

“It’s an exciting area of research, but that’s what it is at this time, very preliminary research," Dr. Glatt said.

Pfizer has added a protease inhibitor into studies of Covid-19 patients who are at increased risk of progressing to severe illness. The protease inhibitor is used in combination with a booster drug, ritonavir, to help it remain in the body longer at higher concentrations. If the study is successful, Pfizer could seek emergency-use authorization by year-end, a spokeswoman said.

Japan-based Shionogi said in July that it had started initial trials of an oral protease inhibitor in healthy subjects in its home country. Shionogi’s drug doesn’t need a booster, according to a spokeswoman. This study should be completed in September and discussions are under way with Japanese authorities about further development, the spokeswoman said.

Preclinical research suggests that Pardes’s drug could be given without a booster, though that must be proven in clinical trials, said Chief Executive Uri Lopatin. Which protease inhibitor is best for patients will have to be learned in clinical trials, he said.

If all goes well with its initial study of healthy volunteers, Pardes plans to test the drug to treat and prevent Covid-19 in further clinical studies beginning in early 2022, Dr. Lopatin said.

Pardes capitalized on published research on compounds studied to treat the coronaviruses SARS and MERS, as well as scientific information in the public domain about the new coronavirus, to speed its identification of a new protease inhibitor for Covid-19, he said.

The startup closed a $52 million first, or Series A, round of financing in January from Foresite, Khosla Ventures and other backers. In June, Pardes decided to merge with a blank-check company created by Foresite to go public and gain access to substantial funding needed to manufacture the drug for clinical trials and eventually make it available to patients, Dr. Lopatin said.