Study: Plasma helped 30 of 50 patients.

More than three quarters of 25 critically ill Houston Methodist COVID-19 patients improved after receiving blood plasma from people who have recovered from the disease, according to the first U.S. study to be published on the century-old therapy’s use against the deadly pandemic.

A preliminary report by the Methodist research team found no adverse side effects and concluded that what’s known as convalescent serum therapy is a safe treatment option for patients with the disease caused by the novel coronavirus circulating globally. The report has not yet been peer reviewed.

Because it is not known if the patients would have improved without the experimental treatment, the report called for a clinical trial comparing patients who receive the plasma therapy to patients who receive either a placebo or some standard of care.

The study, the largest to date assessing the therapy’s use in COVID-19 patients, comes two weeks after study leader Dr. James Musser told the Chronicle that 30 of the first 50 patients treated with the therapy had recovered and gone home. He said then he would be submitting results to a journal shortly.

Methodist gained attention for the therapy in late March when a team of its doctors, along with a team at Mount Sinai Medical Center in New York City, became the first U.S. hospitals to transfuse patients with recovered patients’ blood plasma. The two patients transfused that night at Methodist were among those that recovered and were discharged.

The therapy is based on the idea, well documented in laboratory research, that transfusing plasma from patients who’ve recovered from a virus transfers its healing power. Such plasma contains antibodies made by the immune system to attack the infection.

The therapy, first used during the 1918 Spanish Influenza and last used in the Ebola outbreak of 201416, has become one of the go-to treatments for COVID-19, which has infected more than 1.4 million Americans and killed in excess of 84,000. It’s now been given to thousands of U.S. COVID-19 patients as researchers search for weapons against the novel infection.

The Methodist study included 25 patients, all on oxygen support. Seven days after getting plasma therapy, nine had improved, seven enough to be discharged. At 14

days, another 10 had improved, four enough to be discharged.

The report did not say how many of the patients were on ventilators, typically used on the sickest of COVID-19 patients. Such patients die at a high rate with just supportive care — 39 percent, according to one recent study.

Methodist said a possible randomized trial to be done should evaluate participants based on a number of variables — the timing of the transfusion, the number and volume of transfusions and antibody levels in donor

plasma.

The trial, the report about which was posted on the preprint server medRxiv, represents about a third of the critically ill COVID-19 patients Methodist has treated thus far. Of those 74, 50 have been discharged from the hospital and are recovering. More than 150 recovered coronavirus-infected people have given plasma at Methodist, including many who continuing to make frequent donations, officials said.

Methodist is just one Houston-area hospital providing the therapy. Baylor St. Luke’s Medical Center and Memorial Hermann Health System in the Texas Medical Center have also transfused numerous COVID-19 patients, and the Gulf Coast Regional Blood Center reported two weeks ago it has facilitated transfusions for 12 area hospitals.

The center is looking for additional donors as part of its partnership with Baylor College of Medicine to bring plasma transfusions to more COVID-19 patients in the Houston area.

Nationally, the Mayo Clinic is leading a clinical trial at more than 2,000 hospitals where all of the patients receive the therapy. Johns Hopkins University is conducting a smaller trial in which patients are randomly assigned to receive either the plasma or a placebo.