excerpt from a Stat news article on COVID - 19 therapeutics...competition from Merck and Pfizer.

 https://www.statnews.com/2021/04/09/scientists-work-toward-an-elusive-dream-a-simple-pill-to-treat-covid-19/

The leading contenders

The first drug poised to check all the boxes of an ideal antiviral is molnupiravir, invented at the Emory Institute for Drug Development and developed by Merck and Ridgeback Biotherapeutics. The drug is what’s known as a nucleoside analog, designed to throw a wrench in the process of viral replication by tricking SARS-CoV-2 into corrupting its own genetic material.

Merck is enrolling about 3,000 patients, both hospitalized and recently diagnosed, in a Phase 2/3 trial that will determine whether molnupiravir can help clear SARS-CoV-2 from the body faster than placebo and keep patients out of the hospital. Data from the smaller Phase 2 portion are expected in the coming weeks, and experts are particularly focused on whether Merck’s drug can prevent patients with mild symptoms from developing severe Covid-19.

Behind Merck’s drug is a treatment from Atea Pharmaceuticals that builds on prior antiviral success. Atea’s drug, AT-527, targets an enzyme key to viral replication, a similar approach to Gilead Sciences’ curative treatments for hepatitis C. Later this year, Atea expects to have Phase 2 data on AT-527’s benefits for patients in and out of the hospital. The company is also planning a larger, Phase 3 study on outpatients.

Experts are hopeful that both drugs can make a difference. They’ve selected targets that are likely to minimize the risk of side effects, and they’ve designed studies that should determine whether they work in that key post-diagnosis window. However, some expressed concern that because neither treatment was specifically engineered for SARS-CoV-2, there remains a substantial risk that each will come up short. When it comes to repurposed antivirals, “theoretically they should work great,” Rasmussen said, “but in reality a lot of times they don’t.”

An antiviral from Pfizer, now in the earliest stages of human testing, could address that problem. Catchily named PF-07321332, Pfizer’s drug targets SARS-CoV-2’s backbone enzyme, the linchpin of the virus’s replication process. That enzyme, called 3CL, is one of two that are specific to all coronaviruses. That means if Pfizer can find the right dose, and run the right trials, it might have a treatment not just for SARS-CoV-2 but future pandemic viruses.

“What we might end up doing here is curing the common cold,” Collins said. “Then I wouldn’t have to listen to those jokes anymore.”