A citizen advocacy group is urging Gilead Sciences (GILD) to move forward with the development of antiviral-drug known as GS-441524 – an alternative to remdesivir – or show evidence why the drug would not be effective in treating COVID-19 patients.

The group, Public Citizen, which has the backing of more than 500,000 supporters, claims that Gilead has been “sitting on a potentially promising coronavirus treatment (GS-441524) for months that may offer significant advantages” to treating COVID-19. The group also said that Gilead is looking to “possibly maximize profits,” and is delaying the drug’s development as a result.

“It is sadly predictable that Big Pharma responds to a global pandemic by trying to bring to market only those drugs that maximize its profits,” said Michael Abrams, a health researcher with Public Citizen’s Health Research Group and lead author of the letter.

“What is alarming here is that federal scientists and Trump administration regulators appear to be willing partners with Gilead in decisions that run distinctly counter to the government’s primary imperative of advancing public health during this worldwide crisis.”

The letter from Public Citizen, and two prominent scientists with expertise in cancer research, was also sent to the heads of the National Institutes of Health, the National Institute of Allergy and Infectious Diseases, the U.S. Food and Drug Administration, and Biomedical Advanced Research and Development Authority, along with Gilead on Tuesday.

The letter indicated that remdesivir has been fast-tracked for approval by the U.S. Department of Health and Human Services (HHS) to treat the coronavirus, but GS-441524, which has a similar chemical makeup as remdesivir, has been neglected, Public Citizen said.

The group maintains that there is scientific evidence to suggest the GS-441524 is a better option than remdesivir based on the fact that it has demonstrated effectiveness and safety in cats that were infected with the coronavirus.

The group also suggests that GS-441524 may be better than remdesivir because it has shown antiviral activity against the coronavirus that is “similar” or “superior” to that of remdesivir with low toxicity levels. Public Citizen also claims that the drug stops the reproduction of the coronavirus and could possibly be used as an oral or inhaled form of treatment for the COVID-19 compared to remdesivir’s intravenous use.

Public Citizen also claims that GS-441524 is easier to manufacture than remdesivir and has antivirual therapeutic effects to the lungs.

“It is unclear why Gilead and federal scientists have not been pursuing GS-441524 as aggressively as remdesivir, but the answer may be found in the corporation’s patent holdings,” the letter said.

Public Citizen claims that Gilead holds patents on both GS-441524 and remdesivir with the former drug patent obtained 2010, which the group said could make remdesivir more profitable.

Public Citizen is calling for Gilead and HHS to work collaboratively on the development of GS-441524 as a treatment for COVID-19 or promptly pursue the development of the drug or publicly explain why it is not medically feasible to do so. The group is also asking Gilead to allow federal and academic scientists immediately to pursue the development of the drug if it is unwilling to do so.

Shares of Gilead were trading at $71.25 as of 9:54 a.m. ET, down 48 cents or 0.66%.

Remdesivir is an experimental medication produced by the US laboratory Gilead Sciences
Remdesivir is an experimental medication produced by the US laboratory Gilead Sciences POOL / Ulrich Perrey