PharmaEssentia Corporation (Taiwan Stock Exchange: 6446), the Taiwanese biopharmaceutical company specializing in treatments for myeloproliferative neoplasms, announced on October 19, 2026, that it will present six research posters examining the management of essential thrombocythemia and polycythemia vera at the 18th International Congress on Myeloproliferative Neoplasms in Brooklyn, New York. The findings include a United States claims analysis showing that 55% of patients who began BESREMi (ropeginterferon alfa-2b-njft) as first-line cytoreductive treatment for polycythemia vera remained on therapy at two years. Another analysis found that only approximately one-third of an estimated 159,000 US essential thrombocythemia patients received treatment, with hydroxyurea accounting for 94% of first-line therapy among treated patients. The presentations follow BESREMi’s August 2026 FDA approval for essential thrombocythemia, extending an established polycythemia vera franchise into a second chronic blood cancer.
The research programme covers treatment patterns, discontinuation, long-term complications and molecular responses associated with interferon treatment. A retrospective Chinese analysis of 87 patients with myeloproliferative neoplasms reported that complete hematologic response increased from 62% at three months to 78% at 12 months during BESREMi treatment. A separate Japanese analysis suggested that faster dose escalation produced numerically greater reductions in the JAK2 V617F mutation burden at Week 24 than slower titration. However, these findings come from different populations and study designs, and the observational results should not be interpreted as randomized evidence that BESREMi improves long-term survival or prevents disease progression.
All six posters are scheduled for presentation on October 29, 2026. The programme is particularly relevant because BESREMi is now approved in the United States for adults with both essential thrombocythemia and polycythemia vera, conditions that require prolonged management and carry risks of thrombosis and progression. Its broader use will depend on how clinicians balance hematologic control, molecular response, tolerability, treatment burden and the evidence supporting alternative therapies.
Why does essential thrombocythemia remain dependent on older treatment options?
Essential thrombocythemia is a chronic myeloproliferative neoplasm characterized by excessive platelet production in the bone marrow. Patients may experience headaches, fatigue and disturbances in small blood vessels, while more serious complications include thrombosis and bleeding. The disease is frequently associated with mutations involving JAK2, CALR or MPL, although treatment decisions also depend on age, previous vascular events and other clinical risk factors.
PharmaEssentia’s new US claims analysis estimates that only approximately one-third of 159,000 patients with essential thrombocythemia had received treatment. Hydroxyurea accounted for 94% of initial treatment among those receiving pharmacological therapy, while patients who changed medicines frequently moved between hydroxyurea and anagrelide. These figures illustrate the dominance of established cytoreductive options in recorded treatment patterns.
However, the finding that two-thirds had not received treatment must be interpreted carefully. Not every person diagnosed with essential thrombocythemia requires immediate cytoreductive therapy, and some lower-risk patients may be managed through monitoring or other measures. The claims result therefore identifies a substantial untreated population but does not establish that all those patients were receiving inadequate care.
For patients requiring cytoreduction, treatment tolerability and durability remain important. Hydroxyurea can effectively reduce blood counts, but some patients experience intolerance, treatment resistance or other problems requiring changes in therapy. The potential role of BESREMi is to provide an additional option with a different biological mechanism and an established randomized efficacy dataset.
What did the SURPASS ET trial establish before BESREMi’s FDA approval?
The FDA approved BESREMi for adults with essential thrombocythemia in late August 2026, with the agency publicly announcing the decision on September 3. The pivotal evidence included SURPASS ET, a randomized, open-label Phase 3 study comparing ropeginterferon alfa-2b with anagrelide in 174 adults who were resistant or intolerant to hydroxyurea. Of these participants, 91 received BESREMi and 83 received anagrelide.
According to the FDA-approved prescribing information, 37.4% of BESREMi-treated participants achieved the prespecified durable modified European LeukemiaNet response at both Months 9 and 12, compared with 3.6% receiving anagrelide. The difference was approximately 33.9 percentage points. The endpoint combined appropriate blood count control, absence of disease progression in specified clinical signs and freedom from relevant hemorrhagic or thrombotic events.
The FDA-label figures should be distinguished from the approximately 43% versus 6% response rates reported in earlier company publications. Different analysis definitions and reported populations can produce different estimates from the same clinical development programme. For communicating the current authorized product’s pivotal evidence, the FDA-label analysis provides an appropriate reference.
The trial demonstrated a statistically significant advantage on its defined response measure, but that does not establish superiority for every clinically important outcome. Longer observation is needed to determine how differences in molecular burden and hematologic response translate into prevention of major vascular events, disease progression and survival.
Why is the 55% two-year treatment persistence finding important in polycythemia vera?
Polycythemia vera is another chronic myeloproliferative neoplasm, characterized principally by excessive production of red blood cells. Patients often require long-term measures to control blood counts and reduce thrombotic risk. Treatment may include phlebotomy, low-dose aspirin when appropriate and cytoreductive medicines according to risk and clinical circumstances.
The newly announced US claims analysis found that 55% of patients beginning BESREMi as first-line treatment remained on the medicine after 24 months. This indicates that slightly more than half of the relevant observed population maintained therapy over two years. Treatment persistence can provide useful information about long-term use outside controlled trials.
However, persistence is not equivalent to a successful treatment response. Patients may continue a medicine despite incomplete disease control, while others may discontinue for reasons unrelated to tolerability or effectiveness. Insurance coverage, cost, changes in clinical strategy and patient preference can all influence the length of treatment.
The findings therefore provide information about real-world treatment behavior rather than directly establishing superior efficacy. Understanding the reasons for continuation and discontinuation would help determine whether patients remained on BESREMi because of sustained benefit, acceptable tolerability or other factors.
What do the age-related treatment persistence differences suggest?
PharmaEssentia’s analysis also identified substantial differences in treatment persistence across age groups. Among all patients receiving BESREMi, those younger than 60 years had a reported 24-month persistence rate of 60.5%, compared with 32.0% among older patients. Younger patients also tended to receive the medicine earlier in their treatment sequence.
The difference is notable because older patients with myeloproliferative neoplasms may have additional medical conditions, medication exposure and treatment-related risks. These factors can influence the selection and continuation of cytoreductive therapy. However, the announcement does not establish which individual factors were responsible for the observed persistence gap.
Differences in the timing of treatment initiation may also contribute. Patients receiving BESREMi earlier in their disease course may differ clinically from those switching after previous therapies. Such differences can affect the likelihood of continuing treatment independently of the medicine’s biological efficacy.
The analysis does not demonstrate that BESREMi is inherently better tolerated or more effective in younger adults. A controlled comparison accounting for baseline characteristics would be required to make that claim. The finding instead raises questions about whether older patients face particular barriers to sustained interferon treatment.
How do first-line BESREMi patients differ from those receiving other cytoreductive treatments?
A separate community oncology analysis examined the characteristics of polycythemia vera patients beginning BESREMi or another cytoreductive therapy. Patients starting BESREMi had a median age of 63 years, compared with 73 years among those receiving other treatments, mostly hydroxyurea. Approximately 32% of first-line BESREMi users were classified as low risk, compared with 8% of the comparator treatment population.
The median time from polycythemia vera diagnosis to initiation of cytoreduction was 7.7 months for BESREMi users, compared with 0.6 months for other treatment initiators. PharmaEssentia suggested that the difference was consistent with initial management using phlebotomy and aspirin in some patients. However, the reported interval cannot establish the specific clinical decisions made for each participant.
These findings show that treatment selection in community practice is not random. Physicians may prescribe different medicines to patients with differing ages, risk profiles and disease histories. Consequently, outcomes observed in real-world treatment groups may reflect patient selection as well as differences between the medicines.
The analysis is useful for understanding the commercial and clinical positioning of BESREMi after its expanded authorization. However, it does not provide a valid head-to-head effectiveness comparison with hydroxyurea without appropriate adjustment for baseline differences and other confounding factors.
What do the Japanese results show about faster BESREMi dose escalation?
One of the six presentations examines the relationship between dose escalation and molecular response using exploratory analyses from two Japanese Phase 3 studies in polycythemia vera. The faster titration regimen begins at 250 micrograms, increases to 350 micrograms and then reaches 500 micrograms. It was compared with a slower approach to dose escalation.
The analysis found a numerically greater reduction in JAK2 V617F allele burden at Week 24 with the rapid regimen, reported as 12.66%, compared with 7.50% following slower titration. The groups showed similar complete hematologic response outcomes during the period assessed. These findings suggest that earlier exposure to the higher dose may influence the speed of molecular changes.
However, the results were exploratory, and the announcement does not provide a statistical test establishing that the difference in mutation burden was significant. Nor does it demonstrate that a faster reduction produces better survival or fewer thromboses. Molecular response is biologically relevant but cannot automatically be treated as proof of improved long-term clinical outcomes.
Dose escalation also requires attention to tolerability. The current United States essential thrombocythemia label uses the 250, 350 and 500 microgram escalation schedule followed by maintenance treatment every two weeks, subject to necessary modifications. Appropriate dosing must remain consistent with the relevant indication and prescribing information.
What did the Chinese real-world study reveal about blood count and molecular responses?
Another presentation describes a multicenter retrospective analysis involving 87 Chinese patients with myeloproliferative neoplasms, mainly essential thrombocythemia and polycythemia vera. Participants received BESREMi using the 250, 350 and 500 microgram escalation approach. The study evaluated hematologic control, molecular response and adverse events during treatment.
Complete hematologic response increased from 62% at three months to 78% at 12 months. The researchers also reported that JAK2 V617F allele burden decreased by an average of 1.89% per month of treatment. These findings suggest both blood count improvement and changes in a disease-associated molecular marker among the evaluated patients.
The safety analysis described Grade 1 and Grade 2 adverse events, most commonly abnormal liver function tests. No Grade 3 or higher adverse events were reported in the company’s summary of this 87-patient series. However, a retrospective population of this size cannot reliably exclude uncommon or delayed treatment complications.
The study also lacks a randomized comparator. Differences in previous treatment, baseline disease severity and duration of exposure may influence the observed outcomes. The findings provide supportive experience from routine practice but do not establish that BESREMi is superior to other treatments in the Chinese population.
Does lowering JAK2 V617F allele burden mean BESREMi modifies the disease?
The JAK2 V617F mutation contributes to abnormal signaling in a substantial proportion of patients with polycythemia vera and essential thrombocythemia. The allele burden measures the proportion of relevant genetic material carrying the mutation in a tested sample. A decline during treatment may indicate changes in the population of mutation-bearing cells.
BESREMi is an interferon-based medicine intended to affect disease-associated cells within the bone marrow. Its mechanism differs from therapies that primarily reduce circulating cell counts without necessarily producing comparable molecular changes. PharmaEssentia considers sustained reductions in mutation burden an important part of the medicine’s broader therapeutic potential.
Nevertheless, the clinical significance of molecular response must be demonstrated rather than assumed. It remains necessary to establish whether patients with greater mutation reductions experience fewer thromboses, less progression to myelofibrosis or leukemia, or improved survival. Those outcomes require long-term clinical evidence and appropriate analysis.
The new Japanese and Chinese presentations add information about molecular changes under different dosing and treatment circumstances. They do not establish that the medicine cures either disease or eliminates the need for monitoring. Patients may continue to require ongoing therapy and assessment despite improvement in molecular markers.
What risks must physicians consider when prescribing BESREMi?
BESREMi carries an FDA boxed warning concerning serious neuropsychiatric, autoimmune, ischemic and infectious disorders. Interferon treatment can cause or worsen depression, suicidal thoughts and other significant mood or behavioral changes. It may also contribute to autoimmune complications and affect cardiovascular or other organ systems.
Relevant adverse reactions include liver enzyme elevations, anemia, fever, infection, itching and weight loss. Physicians must assess the patient’s underlying medical conditions and monitor appropriately during treatment. Treatment interruption, dose modification or discontinuation may be necessary when serious adverse effects occur.
These risks are particularly important in chronic myeloproliferative neoplasms because patients may remain on treatment for extended periods. A medicine’s ability to improve blood counts or mutation burden must be considered alongside its long-term tolerability. Observational persistence data can inform this assessment but do not substitute for formal safety evaluation.
The expanded essential thrombocythemia indication provides an additional treatment option, not an obligation to use BESREMi in every patient. Treatment selection should continue to consider disease risk, prior therapy, contraindications and patient preferences.
What will determine BESREMi’s position across the MPN treatment market?
The October congress presentations arrive shortly after an important regulatory expansion. BESREMi had already established a United States indication for adult polycythemia vera in 2021, and the new essential thrombocythemia approval creates opportunities across another chronic blood cancer. The company now has randomized pivotal data supporting its use in a defined treatment-experienced population, supplemented by real-world and exploratory evidence.
The newly presented treatment-gap findings suggest that established therapies still dominate US essential thrombocythemia management. However, market growth cannot be calculated simply by treating every diagnosed but untreated patient as eligible for interferon therapy. Risk stratification, clinical guidelines, reimbursement and patient characteristics will determine actual use.
PharmaEssentia’s real-world analyses may help explain how physicians select patients and why some remain on treatment longer than others. The molecular studies could also inform future research into optimal dosing and the relationship between mutation reduction and long-term outcomes. Each result adds a different form of evidence, but none independently establishes the full comparative value of BESREMi.
The six-poster programme highlights PharmaEssentia’s shift from obtaining regulatory approvals toward understanding how its medicine performs in broader clinical practice. The 55% two-year persistence finding demonstrates meaningful continued use among first-line polycythemia vera patients, while treatment-pattern data identify the continued reliance on older options in essential thrombocythemia.
The next important question is whether expanding use of BESREMi produces sustained clinical benefits that extend beyond blood count normalization and molecular response. Long-term thrombosis, disease progression, safety and treatment discontinuation outcomes will determine how substantially the medicine changes management across these chronic myeloproliferative neoplasms.
