Ruxolitinib Plus Pegylated Interferon Alfa-2a Show Promise in Newly Diagnosed Polycythemia Vera

November 1, 2024

Author(s): Alexandra Gerlach, Associate Editor

Ruxolitinib (Jakafi; Incyte Corp) in combination with pegylated interferon alfa-2a demonstrated efficacy and tolerability in patients with newly diagnosed polycythemia vera (PV). According to the 2-year end-of-study results from the phase 2 COMBI 2 clinical trial (EudraCT2018-004150-13), the treatment improved cell counts, bone marrow cellularity, and fibrosis in patients with PV.1

In the phase 2 COMBI 2 trial, researchers evaluated the safety and efficacy of ruxolitinib and low-dose peg-IFN-α2a in patients with newly diagnosed PV.

Image Credit: © MdBabul – stock.adobe.com

PV is a chronic, progressive myeloproliferative neoplasm characterized by the overproduction of red blood cells. The excess cells thicken the blood, slowing its flow and contributing to serious complications, such as blood clots. Almost all patients with PV have the JAK2V617F mutations, and the JAK2V617F variant allele frequency (VAF) is key for determining outcomes, including thrombosis and progression to myelofibrosis.2-4

Ruxolitinib is a Janus kinase inhibitor approved by the FDA in 2011 and is indicated for the treatment of patients with high-risk MF with reduced abnormal expression of PF4, which can lead to decreased fibrosis. It is additionally indicated as a second-line treatment of PV for patients who have an inadequate response to or cannot tolerate hydroxyurea. In the COMBI 2 trial, researchers assessed the efficacy of ruxolitinib in combination with pegylated interferon alfa-2a (peg-IFN-α2a) (Pegasys ProClick; Genentech), an injection commonly used to treat hepatitis B and C infections. According to data from prior studies, peg-IFN-α2a has been shown to induce durable hematologic and molecular remissions in patients with PV. However, approximately 20% to 40% of patients are intolerant or show limited response to peg-IFN-α2a.5-8

In the phase 2 COMBI 2 trial, researchers evaluated the safety and efficacy of ruxolitinib and low-dose peg-IFN-α2a in patients with newly diagnosed PV in an effort to counterbalance intolerance to peg-IFN-α2a. The primary end point was safety, with secondary end points including efficacy, based on hematologic parameters, quality-of-life measurements, and JAK2V617F variant allele frequency (VAF).8

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High Rates of Polycythemia Vera Remission Seen With Ruxolitinib Plus Peg-IFN

Final results from the phase 2 COMBI II trial demonstrated high rates of remission of newly-diagnosed polycythemia vera (PV) after treatment with ruxolitinib plus pegylated-interferon-α2a (peg-IFN), according to a report published in Blood Advances.

The COMBI I trial previously demonstrated efficacy and safety of the combination of ruxolitinib with peg-IFN among patients who were refractory or intolerant to peg-IFN monotherapy and/or hydroxyurea.

“This study supports the previously described theory that combination therapy with ruxolitinib and peg-IFN may be one of the most promising treatment options in patients with myeloproliferative neoplasms,” the researchers wrote in their report.

In the investigator-initiated, single-center, phase 2 study, researchers treated 25 adult patients with newly-diagnosed PV with ruxolitinib and peg-IFN. All patients underwent pretreatment phlebotomies and patients who were high-risk, aged 60 or older, or who had a prior thrombosis also received hydroxyurea.

The primary endpoint was safety and secondary endpoints included complete remission (CR), peripheral blood count remission (PBCR), and bone marrow histologic remission (BMHR).

The median age of the patients was 70 years and 56% were male. The median number of phlebotomies from diagnosis to study entry was 3. There were 76% of patients who were considered high-risk, 20% had a prior thrombosis, and 12% had splenomegaly. The median hemoglobin was 13.8 g/dL and the median hematocrit was 0.44 IQR. The median variant allele fraction (VAF) of JAK2 V617F at baseline was 54 IQR.

Remission was achieved by 52% of patients by 12 months, with 12% of patients having achieved a CR. At 24 months, the overall remission rate was 56% and the CR rate remained at 12%.

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Pegylated Interferons Have Promise but Also Unmet Potential in MPNs

Jared Kaltwasser

Pegylated interferons are a meaningful therapeutic option for the treatment of myeloproliferative neoplasms (MPNs), but a new review article says more research is needed to better understand the ideal usage of the therapy.

The report was published in Therapeutic Advances in Hematology.

Study investigators said several interferon products are currently available to treat patients with MPNs, but they said the short half-life of interferons and the risk of (AEs) effects have limited their usage. Pegylation can help overcome those issues, they said.

“Many of these shortcomings were addressed by covalently binding polyethylene glycol to the interferon structure, which increases the stability, prolongs activity, and reduces immunogenicity of the molecule,” the authors wrote.

More research is needed to better understand when and in whom pegylate interferon therapy is most effective | Image Credit: Iamnee – stock.adobe.com

They said current National Comprehensive Cancer Network guidelines call for pegylated interferons to be used for polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). Currently, there are 2 pegylated interferons available for patients with MPNs, they said: peginterferon alfa-2a (Pegasys; pharma&) and ropeginterferon alfa-2b-njft (BESREMi; PharmaEssentia). Both medications are recommended as cytoreductive therapies for PV, the investigators said.

Clinical Review of Pegylated Interferons Suggests Formulation and Mechanism of Action May Improve Outcomes for MPN Patients

BURLINGTON, Mass., February 21, 2024–(BUSINESS WIRE)–PharmaEssentia USA Corporation, a subsidiary of PharmaEssentia Corporation (TWSE: 6446), a global biopharmaceutical innovator based in Taiwan leveraging deep expertise and proven scientific principles to deliver new biologics in hematology, oncology and immunology, announced the publication of a manuscript reviewing the clinical safety, efficacy and practical management of treatment with two pegylated interferons – peginterferon alfa-2a and ropeginterferon alfa-2b-njft (marketed as BESREMi®). The manuscript, “Interferons in the Treatment of Myeloproliferative Neoplasms” was co-authored by 12 renowned myeloproliferative neoplasm (MPN) specialists and published in Therapeutic Advances in Hematology. Writing and editorial support were funded by PharmaEssentia, however authors retained full editorial control and provided final approval on all content.
“Interferons are immune modulators that have been used to treat MPNs for more than 35 years. Pegylated interferons are an important therapeutic option and have shown much promise across diseases, including polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF),” said Pankit Vachhani, M.D., study author and Associate Professor of Medicine in Hematology/Oncology at University of Alabama at Birmingham. “The manuscript serves as a tool for clinical practice by highlighting the advantages of pegylated interferons, as well as areas where more research is needed to further refine interferon therapies.”