Protagonist Reports 2-Year Follow Up Data from Rusfertide REVIVE Study at the ASH Annual Meeting Showing Durable Efficacy and No New Safety Signals

Long term follow-up from REVIVE Phase 2 study shows durable hematocrit control, decreased phlebotomy use, long-term tolerability, and no new safety signals in patients with polycythemia vera

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NEWARK, CA / ACCESSWIRE / December 12, 2023 / Protagonist Therapeutics, Inc. ("Protagonist" or the "Company") announced details from five abstracts at the American Society of Hematology 2023 Annual Meeting, including an oral presentation with two-year follow up data from the Phase 2 REVIVE study with rusfertide, a mimetic of the natural hormone hepcidin with potential therapeutic value in the treatment of polycythemia vera (PV) and other disease indications. Copies of the presentations will be available on the Events and Presentations section of the Protagonist website.

Ellen K. Ritchie, M.D., Associate Professor of Clinical Medicine at Weill Cornell Medical College presented long-term follow up data from patients in REVIVE who continued into the open label extension (OLE). The Phase 2 trial consisted of 3 parts including 70 patients in the dose-finding Part 1, 59 patients in the placebo-controlled, randomized withdrawal Part 2, and 58 patients in the OLE. At the end of Part 2, 69% (18/26) of rusfertide patients achieved hematocrit control and remained phlebotomy free at 12 weeks, compared to only 19% (5/27) on placebo (p=0.0003). Among the 58 patients that continued into the OLE, as of October 17, 2023 (data cut-off for the ASH presentation), 57 had been treated for over one year and 37 had been treated for over two years. The median follow-up was 2.1 years and data were provided out to 2.5 years in 21 patients.

"These long-term REVIVE data underscore the impact that rusfertide has on PV patients," noted Dr. Ellen K. Ritchie. "With robust and durable improvements in hematocrit as well as improvement of symptoms as measured by validated patient reported outcomes assessments, we continue to be confident of the value rusfertide offers and its potential as an important future treatment option for patients with polycythemia vera."

Results showed that rusfertide when added to therapeutic phlebotomy with or without cytoreductive therapy through 2 years resulted in:

• long-term durable control of hematocrit well below the 45% threshold, decreased red blood cell counts and decreased phlebotomy use;
• improved and normalized serum ferritin levels; and
• no new safety signals, with the majority of adverse events being grade 1-2 injection site reactions that decreased in frequency over time, or adverse events consistent with comorbidities anticipated in the PV population

Cancers are common in PV patients and in REVIVE, 19 of 70 patients (27.1%) had a history of cancer prior to enrolling in the study. Among these patients, 10 (14.3%) had a history of skin cancer. As of October 17, 2023, there have been 8 patients diagnosed with cancer while on study and 7 (7/70; 10.0%) with skin cancer.