Medtronic and United Therapeutics have terminated development of the Implantable System for Remodulin (ISR) after 12 years of collaboration.

The decision is based on the evolution of treatment options and paradigms for pulmonary arterial hypertension (PAH) patients, as well as anticipated efforts required to satisfy Food and Drug Administration ISR approval conditions.

United Therapeutics will continue to support clinical study participants who use the ISR. United Therapeutics and Medtronic have committed to continue supporting patients currently on the ISR. They will evaluate the feasibility of making replacement pumps available for current ISR patients if and/or when necessary.

“United Therapeutics shares the disappointment felt by so many PAH patients and physicians regarding the discontinuation of the ISR program,” Michael Benkowitz, president and chief operating officer, stated. “We remain committed, however, to bringing new therapies and technologies to patients in the near-term that will improve the management of PAH.”

The FDA approved the ISR in 2018 for adults with functional class I, II and III PAH who  receive intravenous treprostinil therapy. Broad distribution of the ISR was delayed in 2019.