On January 4, PharmaEssentia announced that its new drug, P1101, for the treatment of essential thrombocythemia (ET) has achieved statistically significant positive results in its global multicenter Phase III clinical trial, SURPASS ET. The primary efficacy endpoint yielded a p-value of 0.0001, confirming statistical significance.
CEO Ko-Chung Lin stated that the positive clinical data from SURPASS ET demonstrates the significant efficacy of P1101 in treating the new indication of ET. The company plans to submit regulatory applications for ET in multiple countries, including Taiwan, the United States, Japan, South Korea, and China, later this year. Preparations for pre-launch marketing are already underway, positioning P1101 as a key growth driver for PharmaEssentia's future operations.
Currently, the main treatment for ET is hydroxyurea (HU), an off-label therapy. However, research shows that 20% of ET patients are either intolerant to or develop resistance to HU. The second-line therapy is anagrelide (ANA), which was approved by the U.S. FDA in 1997 and remains the only FDA-approved medication for ET, specifically for patients who cannot tolerate HU or have developed resistance. P1101 has already benefited many polycythemia vera (PV) patients worldwide, and the positive results from the ET clinical trial are expected to extend its benefits to more myeloproliferative neoplasm (MPN) patients in the future.
SURPASS ET is an open-label, multicenter, randomized, active-controlled Phase III clinical trial designed to compare the efficacy, safety, and tolerability of P1101 and ANA as second-line treatments for ET. The trial spanned 12 months, with the primary endpoint being a sustained treatment response at both the 9th and 12th months. Additionally, the trial implemented an accelerated dose escalation regimen for P1101 (250 mcg → 350 mcg → 500 mcg), allowing patients to reach the target dose more quickly with higher initial dosages.
The trial enrolled 174 participants across multiple regions, including the United States, Japan, Taiwan, South Korea, Hong Kong, China, Singapore, and Canada. Of these, 91 participants were randomized to the P1101 group, while 83 were assigned to the ANA group.
According to the intent-to-treat analysis, the response rates at both the 9th and 12th months were as follows: the P1101 group achieved a 42.9% response rate (39/91), compared to 6.0% (5/83) in the ANA group, with a p-value of 0.0001, indicating statistically significant superiority of P1101 over ANA in sustained efficacy.
The treatment response, as defined by the Modified ELN response criteria, includes four components: reduction in peripheral blood cell counts, improvement or stabilization of disease-related signs, significant symptom improvement or disease progression-free status, and absence of bleeding or thrombotic events. All criteria were successfully met.
Additionally, secondary efficacy endpoints, such as allele burden reduction, also yielded highly favorable results.
P1101 is an innovative, long-acting interferon independently developed and manufactured by PharmaEssentia. It has been approved in approximately 40 countries worldwide, including major markets such as the United States, Japan, China, and the European Union, for the treatment of adult patients with polycythemia vera (PV). Both ET and PV belong to the category of myeloproliferative neoplasms (MPN), with a comparable number of patients affected by these diseases.
Resource: 藥華藥治ET新藥 三期臨床試驗數據達標
