Using the card, Gruber usually met that maximum by February, leaving his health insurance to fully cover his in-network medical costs and reducing his cost for the drug to $0 for the rest of the year.

“The real insult here is that they’re taking the money that’s intended to help you,” said Gruber, who had planned to buy a home next year with his savings. “I feel desperate, pressed against the wall, and squeezed.”

Oscar Health is one of many commercial health insurers that use what are often called copay accumulator programs to keep funds that are meant to defray patients’ out-of-pocket costs for expensive specialty drugs. Over the past decade, more insurers have adopted such strategies to reduce their prescription drug costs, according to Avalere Health, a consulting company.

Patients who rely on copay assistance from drugmakers are typically heavy users of healthcare for whom delays in treatment or worsening conditions can lead to higher costs, according to patient advocates.

Matt Choffin, Florida market president for Oscar Health, did not comment on the specifics of Gruber’s case. He said the company uses copay accumulators to manage rising medical and prescription costs and “to keep monthly premiums as low as possible.”