GSK taps experimental arthritis antibody to calm the cytokine storm hitting COVID-19 patients

GlaxoSmithKline is hard at work with partner Sanofi in getting a vaccine tested for COVID-19, but this morning it said it was now also entering the race to treat patients already hit with the disease.

Specifically, the U.K.-based Big Pharma says it has “identified” a monoclonal antibody from its pipeline, anti-GM-CSF (granulocyte macrophage colony-stimulating factor) otilimab, as a “potential treatment for patients who have been hospitalised with severe pulmonary complications related to COVID-19.”

It plans to start midstage testing in the coming weeks in around 800 patients in a randomized, placebo-controlled trial.

The drug is already in trials for arthritis, but like other meds, including some repurposed efforts, GSK hopes its therapy can help those with COVID-19 who are hit with a secondary complication known as a cytokine storm.

This can be fatal and comes as a result of an overreaction of the body’s immune system; it’s also seen in other infections such as influenza.

With SARS-CoV-2, the virus causing the pandemic, immune cells are sent out to the lungs when the virus strikes, which causes inflammation in that area. But sometimes this can go into overdrive and causes hyperinflammation leading to injury or even death in some, and it can also hit younger patients.

In a statement to FierceBiotech, GSK said: “We believe that otilimab may be able to help to block the effects of one of the types of cytokine (known as GM-CSF). We plan to start a phase 2 clinical trial by the end of May.”

As with all experimental drugs, which aren’t of course manufactured to fulfil commercial demand, supply can be an issue, and it’s something we’ve already seen with Gilead’s limited numbers for its recently approved repurposed Ebola drug remdesivir in COVID-19.

GSK tells FierceBiotech that otilimab’s supply is “currently being used for the COVID-19 and RA clinical studies” but that, should the results in COVID-19 go its way, GSK “will explore all options to maximize the supply of otilimab.”

A spokesperson added: “We will work with regulators and manufacturing partners to determine how to provide access of otilimab to patients with COVID-19 who urgently need treatments.”

The pharma wouldn’t answer questions on price and how, if approved, it would be distributed, but said: “We recognize the unprecedented patient need for therapies to treat COVID-19.  Our priority is to help find solutions during this global health emergency. If the study with otilimab is positive, we will work with regulators to make the medicine available to patients as quickly as possible.”

The drug entered a phase 3 trial in rheumatoid arthritis last year and was originally developed by MorphoSys. GM-CSF acts on cells, including macrophages (an immune cell type that plays a key role in the inflammatory process), leading to inflammation, joint damage and pain.

Otilimab works by neutralizing the biological function of GM-CSF by blocking the interaction of GM-CSF with its cell surface receptor.

GSK explained that GM-CSF (granulocyte-macrophage colony-stimulating factor) is a cytokine found in high levels in patients with COVID-19. As otilimab works by blocking the effects of GM-CSF, which it says is found in high levels in COVID-19 patients, GSK explained that it will test "whether a single dose of otilimab could dampen the inflammation in patients with COVID-19 pneumonia.”