COVID-19 pill developers aim to top Merck, Pfizer efforts

Sept 28 (Reuters) – As Merck & Co (MRK.N) and Pfizer Inc (PFE.N) prepare to report clinical trial results for experimental COVID-19 antiviral pills, rivals are lining up with what they hope will prove to be more potent and convenient oral treatments of their own.

Enanta Pharmaceuticals (ENTA.O), Pardes Biosciences, Japan’s Shionogi & Co Ltd (4507.T) and Novartis AG (NOVN.S) said they have designed antivirals that specifically target the coronavirus while aiming to avoid potential shortcomings such as the need for multiple pills per day or known safety issues.

Infectious disease experts stressed that preventing COVID-19 through wide use of vaccines remains the best way to control the pandemic. But they said the disease is here to stay and more convenient treatments are needed.

“We need to have oral alternatives for suppression of this virus. We have people who aren’t vaccinated getting sick, people whose vaccine protection is waning, and people who can’t get vaccinated,” said Dr. Robert Schooley, an infectious diseases professor at UC San Diego School of Medicine.

Pfizer and Merck, as well as partners Atea Pharmaceuticals (AVIR.O) and Roche AG (ROG.S) have all said they could seek emergency approval for their COVID-19 antiviral pills this year.

Rivals are at least a year behind. Pardes began an early-stage trial last month, Shionogi plans to start large-scale clinical trials by year-end, Enanta aims to start human trials early next year and Novartis is still testing its pill in animals.

Enanta Chief Executive Jay Luly said re-purposing drugs originally developed for other viral infections is not an unreasonable approach. But it is not known how potent they will be against COVID-19 or how well they can target lung tissue, where the virus takes hold.

The risk is “if it’s not a great effort …you’ll end up losing time,” Luly said.

Antivirals are complex to develop because they must target the virus after it is already replicating inside human cells without damaging healthy cells. They also need to be given early to be most effective.

Currently, intravenous and injected antibodies are the only approved treatments for non-hospitalized COVID-19 patients.

An effective, convenient COVID-19 treatment could reach annual sales of over $10 billion, according to a recent Jefferies & Co estimate. Merck has a contract with the U.S. government that implies a price of $700 for a course of treatment with its antiviral molnupiravir.

SEARCH FOR AN EASY TREATMENT

Several classes of antiviral drugs are being explored. Polymerase inhibitors such as Atea’s drug – first developed for hepatitis C – aim to disrupt the ability of the coronavirus to make copies of itself. There are also protease inhibitors, like Pfizer’s pill, which are designed to block an enzyme the virus needs in order to multiply earlier in its lifecycle.

We are trying to halt the processes “that allow the virus to set up a replication factory,”…