Janssen stops Phase 3 trial testing high-dose Opsumit in CTEPH

Global UNISUS trial of different Opsumit doses now recruiting PAH patients

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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A Phase 3 clinical trial testing high-dose Opsumit (macitentan) in people with chronic thromboembolic pulmonary hypertension (CTEPH) has ended early after an analysis showed the treatment is unlikely to help patients.

The announcement was made in a press release from Janssen, the company that markets Opsumit.

Opsumit is an oral therapy that works to lower blood pressure by prompting blood vessels to relax and widen. The therapy is currently approved as a treatment for pulmonary arterial hypertension (PAH) at a dosage of 10 mg once per day.

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MACiTEPH was testing if higher Opsumit dose could improve exercise capacity

The Phase 3 MACiTEPH trial (NCT04271475) was designed to test a higher dose of Opsumit (75 mg per day) against a placebo in people with CTEPH, which is a type of pulmonary hypertension caused by blood clots that form in the blood vessels of the lungs.

The main goal of the study, sponsored by Janssen’s subsidiary Actelion, was to test whether Opsumit could improve exercise capacity in adults with inoperable or persistent/recurrent CTEPH, as assessed by changes in the six-minute walk test from the study’s start (baseline) to week 28. Of note, the six-minute walk test is a standard test used to assess exercise capacity that measures the total distance a person is able to walk on a flat, hard surface within six minutes.

In large clinical trials such as MACiTEPH, independent data monitoring committees will routinely conduct analyses testing for futility. This basically involves looking at the available data to see if there’s a reasonable possibility that the trial could have positive results.

Janssen announced that MACiTEPH is now being stopped due to futility following a pre-planned interim analysis that showed the trial was unlikely to meet its goals. Janssen did not provide further details on the data that led to this decision, but the company did note that no new safety issues related to Opsumit have been reported in the trial.

Although MACiTEPH is being discontinued, Janssen is planning to continue running a separate Phase 3 clinical trial called UNISUS (NCT04273945), which is testing varying doses of Opsumit in people with PAH. Participants will be treated with Opsumit at the approved dose of 10 mg/day, or at a higher dose of 75 mg/day (after receiving a lower 37.5 mg/day dose for four weeks), for up to four years.

The study’s main goal is to test whether the higher dose can outperform the lower one at reducing the likelihood of mortality or morbidity events, such as death, hospitalization, lung transplant, or disease progression. Measures of symptom severity and exercise capacity will also be assessed.

The UNISUS study is currently recruiting adults with PAH at more than 200 locations around the world.

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