The Merck logo can be seen on a gate to the Merck & Co campus in Rahway, New Jersey, USA on July 12, 2018.

Brendan McDermid | Reuters

Merck announced Thursday that it would end development of its experimental drug for hospitalized patients with severe Covid-19 after the Food and Drug Administration asked the company to provide additional data to support an emergency clearance.

New Jersey-based Merck acquired the drug MK-7110 through the acquisition of privately held biopharmaceutical company OncoImmune late last year for $ 425 million.

An interim analysis of clinical trial data found the drug improved the chances of recovery for the sickest patients with Covid-19 and decreased the risk of death or respiratory failure.

In February, however, Merck announced that US regulators had requested more data on the drug beyond the phase 3 study that had already been conducted. At that point, the company no longer expected to supply the US with the drug in the first half of 2021.

Due to “regulatory uncertainties” and the time and resources required to provide the additional data, Merck has decided to discontinue development of the drug and instead focus on advancing its other Covid-19 drug and accelerating it focus on the production of the Johnson & Johnson vaccine.

“Because of the additional research that would be required – new clinical trials as well as research related to large-scale manufacturing – MK-7110 is not expected to be available until the first half of 2022,” a press release said Company.

The announcement is yet another disappointment for Merck in its efforts to combat the pandemic.

In January, she announced that she would stop developing her two Covid-19 vaccines. In early studies, both vaccines produced immune responses that were worse than those seen in people who had recovered from Covid-19, as well as those reported for other vaccines, the company said.

As Merck withdraws from MK-7110, the company will continue developing its oral antiviral drug molnupiravir in a phase three clinical trial in out-of-hospital patients with Covid-19.

“We continue to make progress in the clinical development of our antiviral candidate molnupiravir,” said Roy Baynes, Merck’s chief medical officer, in a press release. “Dose-finding data from these studies are consistent with the mechanism of action and provide strong evidence for the antiviral potential of the 800 mg dose.”

–Reuter contributed to this report.