The AIDS Healthcare Foundation (AHF) is accusing Merck of overcharging for the antiretroviral Isentress (raltegravir) and is banning the company’s representatives from its clinics, Agence France-Presse reports.

“We’ve banned representatives from Merck Pharmaceuticals from calling on our physicians in our clinics, which is a common marketing strategy,” said AHF communications director Ged Kinslea. “We are instituting this ban largely because of the egregious pricing policies for their key AIDS drug, Isentress.”

Kinslea continued: “The drug is a good drug. It has fewer side effects…. But it is the single most expensive first-line antiretroviral treatment for AIDS available in the United States and the developing world.”

According to the article, an annual course of Isentress costs about $12,870 in the United States. In Africa, Kinslea said, Isentress costs “about $1,100 dollars per patient, per year—and that’s about 20 times more than other AIDS drugs in Africa.”

In a statement issued by the company two weeks ago, Merck said the price-gouging accusations were false and that the drug had been priced “responsibly…after consultation with respected leaders in the HIV community.”

AHF is based in Los Angeles and provides HIV/AIDS advocacy and medicine across the globe.