Aetna's co-payment reductions will take effect June 1.

(Bloomberg) — Aetna Inc. (NYSE:AET) has agreed to reduce out-of-pocket co-payments for most HIV and AIDS medicines to between $5 and $100 after deductibles, according to the AIDS Institute.

Aetna now places almost all HIV drugs in its highest tier and charges U.S. patients as much as 50 percent, or about $1,000 a month for some popular medicines, the nonprofit institute said Thursday. Cynthia Michener, an Aetna spokeswoman, confirmed the change in policy.

The announcement comes after the AIDS Institute and the National Health Law Program filed a complaint with the U.S. Department of Health and Human Services (HHS) in May 2014 alleging that Aetna, Humana Inc. (NYSE:HUM) and Cigna Corp. (NYSE:CI) tried to steer HIV and AIDS patients away from plans offered in the federal insurance exchange in Florida by restricting coverage of HIV medicines. In mid-level “silver plans” offered in Florida, all three insurers required high out-of-pocket spending, the groups said.

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“Aetna’s announcement will help ensure that people living with HIV/AIDS throughout the country will have greater access to essential medicines at a more affordable cost,” said Michael Ruppal, executive director for the AIDS Institute. “However, there are still many other insurers who are charging patients excessive costs for their HIV medications.”

The company’s co-payment reductions will be effective June 1, and continue nationwide in the individual market through 2016, the AIDS Institute said.

The Patient Protection and Affordable Care Act (PPACA) prohibits insurers from refusing coverage to people who are sick. Advocates of people with illnesses requiring costly treatment, such as AIDS or cancer, have been concerned that insurers would construct benefit packages discouraging sick people from selecting their products.

—With assistance from Alex Wayne in Washington.

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