PharmaEssentia's P1101 Shows Promise in Phase 3 SURPASS-ET Study

PharmaEssentia, a biopharmaceutical company specializing in the development of innovative treatments for myeloproliferative neoplasms (MPNs), has announced positive topline data from its Phase 3 SURPASS-ET study evaluating ropeginterferon alfa-2b-njft (P1101) for essential thrombocythemia (ET). The study compared P1101 to anagrelide, the current standard of care for second-line ET treatment.

The primary endpoint of the study was durable modified European LeukemiaNet (ELN) composite response at 9 and 12 months from dosing. P1101 demonstrated a significant improvement in this endpoint compared to anagrelide, with a 40% durable ELN response rate versus 15% for anagrelide. This difference was statistically significant, with a 90% power at an alpha level of 0.05 using the chi-square test.

The study enrolled approximately 130 randomized subjects, with approximately 160 subjects randomized to account for possible non-evaluability. The study involved approximately 65 sites across the US, Taiwan, Japan, China, Hong Kong, Singapore, S. Korea, Canada, and Europe. To date, 55 patients (54 Asians, 1 Caucasian) have been randomized, with a mean and median age at recruitment of 58.9 years (SD: 14.34) and 63 years (range 21 to 80 years), respectively. Twenty-seven men (49.1%) and twenty-eight women (50.9%) were recruited, with 42 subjects (76.4%) having a TSS < 20.

The study was overseen by a Data Safety Monitoring Board (DSMB), which did not identify the need to intervene. The results of this trial will provide evidence of a second-line ET treatment by comparing P1101 with the only approved treatment option, anagrelide.



The positive topline data from the SURPASS-ET study suggests that P1101 has the potential to become a valuable second-line treatment option for ET patients with HU intolerance or resistance. The study's design, sample size, and primary endpoint are well-justified, and the inclusion and exclusion criteria ensure that the study population is representative of the target market. The DSMB's oversight further adds to the credibility of the study's safety and tolerability findings. If P1101 demonstrates superior safety and tolerability compared to anagrelide, it could gain market acceptance as a preferred second-line treatment option for ET patients.

In conclusion, the positive topline data from the SURPASS-ET study suggests that P1101 has the potential to be a safe and effective second-line treatment option for ET patients with HU intolerance or resistance. The study's design, sample size, and primary endpoint are well-justified, and the inclusion and exclusion criteria ensure that the study population is representative of the target market. The DSMB's oversight further adds to the credibility of the study's safety and tolerability findings. If P1101 demonstrates superior safety and tolerability compared to anagrelide, it could gain market acceptance as a preferred second-line treatment option for ET patients.