Regeneron Pharmaceuticals Inc on Tuesday said its experimental two-antibody cocktail reduced viral levels and improved symptoms in non-hospitalised Covid-19 patients, enhancing its chances of becoming a treatment for the disease that has killed over a million people worldwide.
"We hope these data will support an EUA" (emergency use authorization) from the US Food and Drug Administration, Regeneron Chief Scientific Officer George Yancopoulos said on a conference call.
The FDA can authorise emergency use of a drug before completing its review for a formal approval.
The treatment, REGN-COV2, is also being studied for use in hospitalised patients, and for prevention of infection in people who have been exposed to Covid-19. Regeneron declined to comment on when those trial results are expected.
"It is unclear, though possible, that the Regeneron cocktail could work in a hospital setting where the patient is already severely ill and has a high viral load," Jefferies analyst Michael Yee said in a research note.
Yancopoulos said that in order for REGN-COV2 to be used in the studied patient population - people with mild-to-moderate Covid-19 - routine diagnostic tests would be needed. Therapeutic use "is going to depend on having the right diagnostic tools available," he said.
Shares of Regeneron were up 2% at $585.40 after hours.
Trial results for the first 275 patients showed the biggest effect in patients who did not create high levels of their own antibodies against the virus. That suggests the REGN-COV2 could help patients whose own immune system is not strong enough to combat the virus, Regeneron said.
The drug is part of a class of biotech therapies known as monoclonal antibodies. Several companies are using the technology to manufacture copies of human antibodies to the new coronavirus.
Regeneron believes its dual-antibody formula will limit the ability of the virus to escape detection and attack.
Eli Lilly & Co earlier this month released data showing that one of its monoclonal antibodies lowered patient virus levels and could reduce the need for patients to be hospitalised.
Regeneron tested two different doses of REGN-COV2 in two patient populations: those who had mounted an effective immune response on their own (seropositive), and those whose immune response was not yet adequate (seronegative).
In seronegative patients, the median time to symptom relief was 13 days for the placebo group, 8 days for the high-dose group and 6 days for the low-dose group.
Regeneron said REGN-COV2 rapidly reduced virus levels in seronegative patients. In addition, patients with higher virus levels at the start of the trial had correspondingly greater reductions in viral load with REGN-COV2, which is given by intravenous infusion.
"The data are favorable for seronegative patients," Yee said.
The US government in June awarded Regeneron a $450 million supply contract for up to 300,000 doses of the antibody cocktail.
Swiss drugmaker Roche Holding AG last month agreed to boost overall manufacturing capacity for REGN-COV2 by at least three-and-a-half times. Under the deal, Regeneron would handle US sales of the treatment and Roche would be responsible for the rest of the world.