What happened

Shares of Mesoblast (MESO -2.50%) rose as much as 218.9% after the company reported promising early-stage results from a small study in COVID-19 patients with acute respiratory distress syndrome (ARDS). The Australian stem cell company's product candidate, remestemcel-L, was administered to 12 patients on mechanical ventilators at New York City's Mt. Sinai Hospital. Doctors reported that 10 patients survived (marking a survival rate of 83%), nine were removed from ventilator support at a median of 10 days (75%), and seven were discharged from the hospital (58%). 

Although the results are from only 12 people, the outcomes are remarkable. A recent observational study of more than 2,600 COVID-19 patients who were placed on mechanical ventilators in New York City found that 88% died. 

As of 11:04 a.m. EDT, the pharma stock had settled to a 132.6% gain.

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So what

Mesoblast is developing remestemcel-L to treat a range of health disorders. The cell therapy is based on allogeneic mesenchymal stem cells (MSCs), which play a crucial role supporting normal biological functions. MSCs secrete molecules that trigger blood vessel regeneration, repair tissues in the heart and brain, and moderate the immune system. 

The immunomodulation aspect of MSCs, and possibly remestemcel-L, is what might explain the encouraging results from the trial of COVID-19 patients in New York City. Patients are placed on mechanical ventilators because of an overwhelming immune response, which causes runaway inflammation that leads to ARDS and can progress to organ failure and death. If remestemcel-L helps to combat the body's inflammatory responses, then it could help to significantly reduce fatal outcomes related to COVID-19.

Now what

Many companies have attempted to develop stem cell therapies for a range of diseases. Pretty much all have failed. Given the current state of the world, that track record might do little to deter health systems desperate for solutions. Mesoblast remains unproven, but if the results from the first 12 patients treated with remestemcel-L hold up in larger populations, then it could offer a promising treatment for the most significant cause of COVID-19 deaths. Right now investors should remain cautious until more detailed information is available.