Clinical outcomes of patients with myelofibrosis after immediate transition to momelotinib from ruxolitinib

Myelofibrosis and anemia: A German claims data analysis to describe epidemiology and current treatment

OBJECTIVES

There is limited data on the incidence, prevalence, and treatments for myelofibrosis (MF) in Germany. This retrospective study examined claims data from 3.3 million insured individuals, spanning from 2010 to 2021.

METHODS

Four sensitivity scenarios were explored to identify cases of MF. Point prevalence and cumulative incidence of MF were determined as of December 31, 2021, and within 2021, respectively. A cross-sectional analysis used the main scenario definition of MF to identify cases and evaluate the period prevalence of patients receiving treatment for symptoms and/or splenomegaly, including first-line (1L) Janus kinase inhibitor (JAKi), second-line, or further (2L+) MF-related treatment therapies during 2021. The prevalence of anemia treatment was also reported.

RESULTS

The estimated standardized point prevalence of MF on December 31, 2021, was 9.9-12.4 cases per 100 000 persons, and cumulative incidence in 2021 was 1.2-1.8 cases per 100 000 persons. Standardized period prevalence in 2021 for MF patients receiving 1L JAKi and/or 2L+ MF-related treatment was 4.0 cases per 100 000. Among these patients, 47.1%-53.7% required treatment for anemia, resulting in a period prevalence of 1.9-2.2 cases per 100 000 individuals.

CONCLUSION

The data reveal gaps in MF treatments and the need to improve patient quality of life.

Momelotinib versus Continued Ruxolitinib or Best Available Therapy in JAK Inhibitor-Experienced Patients with Myelofibrosis and Anemia: Subgroup Analysis of SIMPLIFY-2

INTRODUCTION

Some Janus kinase (JAK) inhibitors such as ruxolitinib and fedratinib do not address and may worsen anemia in patients with myelofibrosis. In these cases, the JAK inhibitor may be continued at a reduced dose in an effort to maintain splenic and symptom control, with supportive therapy and/or red blood cell (RBC) transfusions added to manage anemia. This post hoc descriptive analysis of the phase 3 SIMPLIFY-2 trial evaluated the relative benefits of this approach versus switching to the JAK1/JAK2/activin A receptor type 1 inhibitor momelotinib in patients for whom anemia management is a key consideration.

METHODS

SIMPLIFY-2 was a randomized (2:1), open-label, phase 3 trial of momelotinib versus best available therapy (BAT; 88.5% continued ruxolitinib) in JAK inhibitor-experienced patients with myelofibrosis (n = 156). Patient subgroups (n = 105 each) were defined by either baseline (1) hemoglobin (Hb) of < 100 g/L or (2) non-transfusion independence (not meeting the criteria of no transfusions and no Hb of < 80 g/L for the previous 12 weeks); outcomes have been summarized descriptively.

RESULTS

In both subgroups of interest, week 24 transfusion independence rates were higher with momelotinib versus BAT/ruxolitinib: baseline Hb of < 100 g/L, 22 (33.3%) versus 5 (12.8%); baseline non-transfusion independent, 25 (34.7%) versus 1 (3.0%). Mean Hb levels over time were also generally higher in both subgroups with momelotinib, despite median transfusion rates through week 24 with momelotinib being comparable to or lower than with BAT/ruxolitinib. Spleen and symptom response rates with momelotinib in these subgroups were comparable to the intent-to-treat population, while rates with BAT/ruxolitinib were lower.

CONCLUSION

In patients with moderate-to-severe anemia and/or in need of RBC transfusions, outcomes were improved by switching to momelotinib rather than continuing ruxolitinib and using anemia supportive therapies.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02101268.

Momelotinib versus ruxolitinib in JAK inhibitor-naïve patients with myelofibrosis: an efficacy/safety analysis in the Japanese subgroup of the phase 3 randomized SIMPLIFY-1 trial

Momelotinib, an oral Janus kinase (JAK) 1/2 and activin A receptor type 1 inhibitor, improved symptoms, splenomegaly, and anemia in patients with myelofibrosis (MF). This sub-analysis of SIMPLIFY-1 evaluated the efficacy and safety of momelotinib versus ruxolitinib in Japanese patients with JAK inhibitor (JAKi)-naïve MF. Patients were randomized 1:1 to receive momelotinib 200 mg once daily or ruxolitinib 20 mg twice daily (or modified based on label) for 24 weeks, after which patients could receive open-label momelotinib. The primary endpoint was splenic response rate (SRR; ≥ 35% reduction in spleen volume) at 24 weeks; main secondary endpoints were total symptom score (TSS) response (≥ 50% reduction) and transfusion independence (TI) rates. Fifteen Japanese patients (momelotinib, n = 6; ruxolitinib, n = 9) were enrolled; all completed treatment. At Week 24, SRR was 50.0% with momelotinib and 44.4% with ruxolitinib. TSS response rates were 33.3% and 0%, and TI rates were 83.3% and 44.4%. Any-grade treatment-related adverse event (TRAE) rates were 83.3% with momelotinib and 88.9% with ruxolitinib. Grade 3/4 TRAE rates were 0% and 55.6%, with specific events being anemia (55.6%) and vertigo (11.1%) with ruxolitinib. Momelotinib was well tolerated, improved spleen and symptom responses, and reduced transfusion requirements in Japanese patients with JAKi-naïve MF.

Momelotinib for the treatment of myelofibrosis

ABSTRACT

In September 2023, the US Food and Drug Administration approved momelotinib for the treatment of myelofibrosis (MF) with anemia, marking the fourth US regulatory approval of a Janus kinase inhibitor for MF. A positive opinion from the European Medicines Agency followed in November 2023. Momelotinib's ability to address splenomegaly, symptoms, and anemia, including in patients with thrombocytopenia (with platelet counts of ≥25 × 109/L), the ease of switching from ruxolitinib, and good tolerability uniquely position it to substantially impact the MF treatment landscape.

Momelotinib vs. ruxolitinib in myelofibrosis patient subgroups by baseline hemoglobin levels in the SIMPLIFY-1 trial

A key hallmark of myelofibrosis is anemia, which ranges from mild to severe based on hemoglobin levels. To more clearly define outcomes with the Janus kinase (JAK) 1/JAK2/activin A receptor type 1 inhibitor momelotinib by anemia severity, we performed a descriptive post hoc exploratory analysis of the double-blind, randomized, phase 3 SIMPLIFY-1 study (NCT01969838; N = 432, JAK inhibitor naive, momelotinib vs. ruxolitinib); subgroups were defined by baseline hemoglobin: <10 (moderate/severe), ≥10 to <12 (mild), or ≥12 g/dL (nonanemic). Spleen and symptom results were generally consistent with those previously reported for the intent-to-treat population. In anemic subgroups, momelotinib was associated with higher rates of transfusion independence and reduced/stable transfusion intensity vs. ruxolitinib. No new or unexpected safety signals were identified. Overall, momelotinib provides spleen, symptom, and anemia benefits to JAK inhibitor-naive patients with myelofibrosis regardless of baseline hemoglobin level, and greater anemia-related benefits vs. ruxolitinib in patients with hemoglobin <12 g/dL.