Dive Insight:

The coronavirus pandemic has made winners out of previously unproven biotechs like Moderna and BioNTech, which each developed strongly successful vaccines in record time. But it’s also featured surprising setbacks for some of the world’s leading infectious disease companies, like Sanofi, GlaxoSmithKline and Merck.

Sanofi and GSK, for instance, had to make a new version of an experimental coronavirus vaccine they teamed up to develop after their first formulation was judged too weak to advance. Both still aim to bring coronavirus shots to market. But they’ve since agreed to help other companies, like BioNTech and Novavax, manufacture vaccines that have proven safe and effective in clinical testing.

Merck has had to dial back its ambitions as well. Though the pharmaceutical giant was a latecomer to coronavirus vaccine and drug development, Merck used a flurry of deals last year to amass four different programs meant to either prevent COVID-19 or treat different stages of the disease. It acquired two vaccines when it bought privately held biotech Themis and formed an alliance with the nonprofit group IAVI. Then it added two therapeutics — MK-7110 and molnupiravir — by acquiring OncoImmune and partnering with Ridgeback.

That portfolio, however, has largely come up empty. Merck discontinued both vaccines in January. And now the OncoImmune drug has been shelved as well.

Merck acquired OncoImmune after MK-7110 after preliminary results in a small Phase 3 study showed that it appeared to help patients hospitalized with COVID-19 recover more quickly. That finding appeared to position Merck to bring the drug to market quickly via an emergency clearance request.

But the Food and Drug Administration requested multiple new trials and work to scale up manufacturing. Those “uncertainties,” along with the availability of other COVID-19 treatments for hospitalized patients — like Veklury, the steroid dexamethasone and Eli Lilly’s baricitinib — led Merck to discontinue the program, the company said in a statement.

The drugmaker’s hopes for treating COVID-19 have now come down to molnupiravir, an antiviral pill Ridgeback licensed from Emory University. The two companies had been testing molnupiravir in both inpatient and outpatient settings, and the drug has shown the potential to help patients clear the virus more quickly.

But hospitalized patients, who are well into their disease course, appeared unlikely to benefit from treatment based on interim results from a mid-stage trial. Merck will instead focus on patients who haven’t had symptoms as long, a group in which the drug’s effects appear to be stronger.

The company will begin a Phase 3 trial in patients with mild-to-moderate COVID-19, have had symptoms for five days or less and are at high risk of disease progression. It also intends to study the drug as a preventive treatment for people exposed to infection.

Synthetic antibody drugs from Regeneron and Eli Lilly have been shown to reduce hospitalizations and deaths in both of those patient groups. But an effective oral antiviral could still be a big help in fighting the pandemic given its convenience and the ease with which it can be manufactured and distributed. Antibody drugs are complex to make and are typically infused in healthcare settings, though Regeneron recently proved an at-home injection can be effective as well.

Merck expects results from its Phase 3 study of molnupiravir in September or October. The prophylaxis trial should begin in the second half of 2021.

Pfizer, Atea Pharmaceuticals and partner Roche, as well as an alliance between Molecular Partners and Novartis, are also developing oral COVID-19 drugs.