One of the promising new drugs being tested against the deadly Ebola virus failed this week to save a surgeon from Sierra Leone, flown in for treatment at a Nebraska hospital.

Dr. Martin Salia, a permanent U.S. resident, died Monday, according to the hospital. He arrived in Omaha Saturday, having left Freetown Friday by air ambulance. He was immediately transported to the Nebraska Medical Center in critical condition.

“It is with an extremely heavy heart that we share this news,” Dr. Phil Smith, medical director of the Biocontainment Unit at the Nebraska Medical Center, said in a statement Monday. “Despite our best efforts, we weren’t able to save him.”

Salia, 44, was not able to walk off the plane, as other patients brought to the U.S. have been able to do. Instead, he was taken off the plane in an isopod, a special device designed to keep contagion from spreading. He was placed on a stretcher and loaded into an ambulance. His wife reportedly agreed to reimburse the U.S. government for the expense of his medical evacuation—approximately $100,000—according to MailOnline, a U.K. media outlet.

He was suffering from kidney and respiratory failure and was placed on dialysis, a ventilator and multiple medications to support his organ system. He was also given a dose of convalescent plasma and ZMapp therapy.

Salia was the chief medical officer and surgeon at Kissy United Methodist Hospital, which is not an Ebola treatment center, in Freetown, Sierra Leone, when he fell ill.

Salia initially tested negative for the disease in Freetown, leading him to believe he suffered from malaria. His colleagues embraced him, celebrating the good news. He ultimately tested positive for the virus Nov. 10. The hospital has since been closed, and three of his colleagues are in isolation over Ebola fears.

Ebola has killed more than 5,000 people in West Africa, mostly in Liberia, Sierra Leone and Guinea.