Kiladjian, Jean‐Jacques

Abstract Most myelofibrosis (MF) drug approvals by Health Authorities are based on 1 or 2 outcome measures such as spleen volume reduction and/or improved quality-of-life. This 1–2 dimensional approach fails to capture the clinical complexity of MF. A European LeukemiaNet (ELN) taskforce developed a composite endpoint which allows multiple outcomes to be simultaneously measured. The panel used the Desirability-Of-Outcome-Ranking (DOOR) method to assign 25 outcomes into 4 quartiles based on a multi-dimensional desirability score and build a 5-layer composite outcome named Desirability-of-Myelofibrosis-Outcomes (DEMYO). Outcome operational definitions were tested by Delphi consensus and correlations with survival validated by a literature review. The outcomes assigned to the first two quartiles were negatively correlated with leukemia-free survival and survival. DEMYO comprehensively captures relevant MF clinical features and meaningful endpoints. Despite DEMYO requires validation based on available trial data, it is expected to improve the quality of Health Authority approvals for new drugs for MF.

Abstract “Nonclassical” myeloproliferative neoplasms (MPNs) and myelodysplastic/myeloproliferative neoplasms (MDS/MPNs) represent a heterogeneous group of malignancies characterized by a wide range of clinical manifestations. Unlike classical MPNs, there is no standardized management approach for these conditions, particularly concerning the indications for and management of allogeneic hematopoietic cell transplantation. To address this gap, the European Society for Blood and Marrow Transplantation (EBMT) Practice Harmonization and Guidelines (PH&G) Committee and the Chronic Malignancies Working Party (CMWP) have collaborated to develop shared guidelines aimed at optimizing the selection and management of patients with these rare forms of neoplasms. A comprehensive review of the literature from the publication of the revised fourth edition of the (2016) World Health Organization classification onward was conducted. A multidisciplinary group of experts in the field convened to produce this document, which was developed through multiple rounds of draft circulation. Key recommendations include the early identification of potential transplant candidates, particularly in cases of chronic neutrophilic leukemia, chronic eosinophilic leukemia (CEL)/CEL, not otherwise specified (CEL-NOS), myeloid/lymphoid neoplasm with eosinophilia and tyrosine kinase gene fusions with FGFR1, JAK2, ABL1, and FLT3 rearrangements, MDS/MPN with neutrophilia/atypical chronic myeloid leukemia, and MDS/MPN, NOS. For patients with MPN, NOS/MPN unclassifiable, standard recommendations for myelofibrosis should be applied. Similarly, in MDS/MPN with thrombocytosis, transplantation is recommended on the basis of established MDS guidelines. Given the current lack of robust evidence, this document will serve as a valuable resource to guide future research activities, providing a framework for addressing critical unanswered questions and advancing the field.

Background New therapies for myelofibrosis (MF) are being developed but how these compare with current therapies is limited to analyzing single outcome measures such as spleen volume reduction or quality-of-life (QoL). However, these outcome trajectories might diverge and some endpoints may not be clinically relevant. To remedy this an ELN (European LeukemiaNet) taskforce developed a composite endpoint using the Desirability-Of-Outcome-Ranking (DOOR) method which allows multiple outcomes to be simultaneously considered and therapies achieving diverging endpoints compared. Methods An Expert Panel used DOOR to divide outcome relevancy into 8 dimensions: clinical meaningfulness, modifiability, reliability, feasibility, decisional value, acceptability, frequency, and cost. Next, a weight was assigned to each dimension using the mean Likert score assigned by the panelists. Next, the panel validated which dimensions were met by each of 30 outcomes most frequently listed by clinical trials. A weighted score (WS) for each outcome was calculated based on weights assigned to a dimension and accomplishment rates assigned to outcomes. Outcomes were then distributed into quartiles. Next, operational definitions of outcomes were tested in Delphi consensus method requiring > 75% agreement. Last, a literature review indicated correlations of the outcomes ranked in the 1st 2 quartiles with survival. Results Three composite endpoints were developed and named DEMYOs (DEsirability-of-MYelofibrosis-Outcomes). DEMYO-1, the proportion of people alive and free of severe vascular events, blast transformation, severe anaemia and thrombocytopenia and very-severe symptom burden, encompassed outcomes in the 1st quartile (WS > 29.5) and is the proposed composite endpoint for trials of people with advanced JAK-inhibitor refractory MF. DEMYO-2, defined as the proportion of people alive and free of accelerated or blast phase, severe or worsening anaemia, severe and major vascular events, severe or symptomatic splenomegaly, severe or worsening symptoms and any emergent adverse genetic abnormality, included the outcomes ranked in the 1st 2 quartiles (WS > 26.5) and is proposed for trials of people with a sub-optimal response to JAK-inhibitors. DEMYO-3, defined as the proportion of people alive and free of blast transformation, vascular events, severe, symptomatic or worsening clinical features and of worsening prognostic co-variates, included outcomes in the 1st 3 quartiles (WS > 23.5) and is proposed for trials of people not yet receiving JAK-inhibitors. Interpretation DEMYO composite endpoints capture relevant clinical features of MF and represent endpoints important to patients, physicians and other stakeholders. DEMYO validation is feasible by available trial data and, once validated, the composite endpoints can be endorsed by medicines regulatory agencies. DOOR proved feasible and robust in this 1st-in-haematology application and we encourage further use. No funding

ABSTRACTSpleen volume reduction (SVR) is a key endpoint in inhibitors of Janus kinase (JAK) inhibitor studies. Retrospective analyses have demonstrated an association between SVR and improved overall survival (OS) among patients treated with ruxolitinib with a platelet count > 100 × 109/L. Whether this association occurs in patients with thrombocytopenia is unclear. Pacritinib, a JAK2/IRAK1/ACVR1 inhibitor, demonstrated improved SVR versus best available therapy (BAT [best available therapy]; including ruxolitinib) in patients with myelofibrosis and platelet counts ≤ 100 × 109/L in the PERSIST‐2 study. Patients on study at the start of the 12‐week SVR window on pacritinib 200 mg twice daily or BAT were included. OS was evaluated among SVR responders versus non‐responders using different SVR thresholds (≥ 35%, ≥ 20%, ≥ 10%, and > 0%). Among patients on pacritinib (n = 89), SVR ≥ 10% demonstrated the greatest separation in OS curves between responders and non‐responders (HR, 0.00; 95% CI, 0.00–0.14; p < 0.01), though SVR ≥ 0% and SVR ≥ 20% were also associated with improved OS. No SVR threshold conferred OS benefit on BAT (n = 84), including ruxolitinib (n = 39). In patients with myelofibrosis and platelets ≤ 100 × 109/L, achieving SVR on pacritinib, but not BAT (including ruxolitinib), was associated with significant OS benefit, suggesting that pacritinib may offer a unique survival advantage in patients with myelofibrosis and thrombocytopenia who achieve any SVR. Trial Registration: ClinicalTrials.gov number: NCT02055781

Abstract With emerging new drugs in myelofibrosis (MF), a robust and harmonized framework for defining the severity of anemia and response to treatment will enhance clinical investigation and facilitate interstudy comparisons. Accordingly, the lead authors on the 2013 edition of the International Working Group–European LeukemiaNet (IWG-ELN) response criteria in MF were summoned to revise their document with the intent to (1) account for gender-specific differences in determining hemoglobin levels for eligibility criteria; (2) revise the definition of transfusion-dependent anemia (TDA) based on current restrictive transfusion practices; and (3) provide a structurally simple and easy to apply response criteria that are sensitive enough to detect efficacy signals (minor response) and also account for major responses. The initial draft of the 2024 IWG-ELN proposed criteria was subsequently circulated around a wider group of international experts and their feedback incorporated. The proposed articles include new definitions for TDA (≥3 units in the 12 weeks before study enrollment) and hemoglobin thresholds for eligibility criteria (&lt;10 g/dL for women and &lt;11 g/dL for men). The revised document also provides separate (TDA vs non-TDA) and graded (major vs minor response) response criteria while preserving the requirement for a 12-week period of screening and observation on treatment.

Abstract The ACE-536-MF-001 trial enrolled patients with myelofibrosis (n = 95) into 4 cohorts: patients in cohorts 1 and 3A were non–transfusion dependent (NTD) and had anemia; patients in cohorts 2 and 3B were transfusion dependent (TD); and patients in cohort 3A/3B had stable ruxolitinib treatment before and during the study. All patients received luspatercept (1.0-1.75 mg/kg, 21-day cycles). Treatment was extended if clinical benefit was observed at day 169. The primary end point was anemia response rate (NTD, ≥1.5 g/dL hemoglobin increase from baseline; TD, transfusion-independence) over any 12-week period during the primary treatment period (weeks 1-24). Overall, 14% of patients in cohorts 1 and 3A, 10% in cohort 2, and 26% in cohort 3B met the primary end point. In cohorts 1 and 3A (NTD), 27% and 50% of patients, respectively, had mean hemoglobin increase of ≥1.5 g/dL from baseline. Among TD patients, ∼50% had ≥50% reduction in transfusion burden. Reduction in total symptom score was observed in all cohorts, with the greatest response rate seen in cohort 3A. Overall, 94% of patients had ≥1 adverse event (AE); 47% had ≥1 treatment-related AE (TRAE; 11% grade ≥3), most frequently hypertension (18%), managed with medical intervention. One patient had a serious TRAE leading to luspatercept discontinuation. Nine patients died on treatment (unrelated to study drug). In most patients, ruxolitinib dose and spleen size remained stable. In patients with myelofibrosis, luspatercept improved anemia and transfusion burden across cohorts; the safety profile was consistent with previous studies. This trial was registered at www.ClinicalTrials.gov as #NCT03194542.

Background: Pacritinib is a JAK1-sparing inhibitor of JAK2/IRAK1/ACVR1 that demonstrated symptom benefit measured by TSS (v2.0, excluding tiredness) vs best available therapy (BAT) in PERSIST-2, which enrolled cytopenic myelofibrosis patients with platelets ≤100×10 9/L. Recent datashowed that in patients with cytopenic MF, a ≥10% reduction in spleen volume at 12 weeks is associated with improved survival in patients treated with pacritinib ( Ajufo H, et al., J Clin Oncol;2023:14(16):Suppl). Surprisingly, this association was not confirmed in patients treated with BAT (82% of whom were on ruxolitinib). The association between other important measures of clinical benefit such as symptom burden reduction and anemia improvement on survival in patients treated with pacritinib has not previously been described. Methods: Patients randomized to pacritinib 200 mg BID and to BAT on PERSIST-2 were included if they were alive and on study at the start of the week 12 efficacy assessment period. Survival was assessed by Total Symptom Score (TSS; v2.0 excluding tiredness) reduction at various thresholds (≥50%, ≥20%, ≥10%, &gt;0%) and transfusion independence (TI) response. TI was assessed among patients who required red blood cell (RBC) transfusion at baseline (within 90 days) and was defined, for the purposes of a landmark survival analysis, as the absence of RBC transfusions over any 12-week period from first dose through week 14 (allowing for a ±2-week window around week 12). Overall survival (OS) was estimated via the K-M method following the landmark approach; survival in responders vs non-responders was compared using the log-rank test. Results: Of the 59 patients treated with pacritinib who had a reduction of TSS≥10%, the median age was 67 years, 25% had a baseline high-risk DIPSS, median platelet count was 61 x10 9/L, median hemoglobin was 9.7 g/dL, and baseline TSS was 19.1. Reduction of TSS≥10% was associated with improved OS, with 1 death among 59 responders vs 4 deaths among 30 non-responders (hazard ratio [HR]=0.12, 95% confidence interval [CI]: 0.01, 0.79] P=0.021, Fig 1a). Similar to spleen volume reduction, the association between TSS response and OS weakened at more stringent TSS response thresholds (Fig 1c, e), with the BAT arm not showing an association between TSS response and OS at any threshold. (Fig 1b, d, f). In order to assess the relationship of specific TSS domains and survival , a landmark OS analysis was performed based on ≥20% reduction in physical function scores (sum of ‘tiredness’ and 'inactivity'), spleen-related symptom scores (sum of 'abdominal discomfort', ‘early satiety’, and 'left rib pain'), and cytokine-related symptom scores (sum of 'itching', ‘night sweats’, and ‘bone pain‘). For cytokine-related symptoms, the number of deaths in PAC responders was significantly different compared to non-responders, with 0 deaths among 35 responders vs 2 among 15 non-responders ( P=0.0325). Conversely the deaths among responders (2/22) vs non-responders (2/20) were not significantly different in the BAT arm. For the physical function and spleen-related symptom subscales, no significant differences between PAC responders and non-responders was observed (HR=0.60; 95% CI [0.05, 6.74] P=0.679) and (HR=0.26; 95% CI 0.02, 2.93, P=0.2435) respectively. Among 36 patients on PAC who received RBC transfusions at baseline, 7 achieved TI over at least a 12-week period up to the time of the landmark analysis. There were no deaths among TI responders compared to 2 (6.9%) among TI non-responders. There were too few TI responders on BAT (only 2 out of 38) to assess the impact on survival. Conclusion: In cytopenic myelofibrosis patients enrolled in PERSIST-2, having a reduction of TSS≥10% on full-dose PAC was associated with OS benefit - a finding that has not been noted with other JAK inhibitors to date. By contrast, this association was not found with BAT, (82% of these patients received ruxolitinib). Thus, reductions in TSS in patients treated with PAC were associated with an OS benefit. It is possible that pacritinib, with its distinctive mechanism of action, may offer a unique survival advantage for MF patients with moderate or severe thrombocytopenia, and further studies are required to understand the potential mechanisms of these distinct clinical observations. Study funded by CTI BioPharma Corp., a Sobi company.

Myelofibrosis (MF) is a chronic myeloproliferative neoplasm that typically manifests with debilitating symptoms that progressively worsen, negatively impacting patients’ quality of life. Fatigue is a multifactorial and burdensome MF-related symptom due to its severity, persistence, and prevalence, with anemia a contributing factor and major unmet need. Clinical trials of the Janus kinase (JAK)1/JAK2/activin A receptor type 1 inhibitor momelotinib have shown consistent anemia benefits, in addition to improvements in MF-related symptoms. The phase 3 MOMENTUM trial in symptomatic and anemic patients met its primary end point, with a greater proportion having a Myelofibrosis Symptom Assessment Form (MFSAF) Total Symptom Score (TSS) reduction ≥50% at week 24 with momelotinib versus danazol. To support the positive primary end point result, we conducted longitudinal, responder, and time-to-event analyses of patient-reported outcomes from MOMENTUM, as measured by the MFSAF, European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30), and Patient-Reported Outcomes Measurement Information System (PROMIS) assessments. These analyses demonstrated rapid and durable response benefits with momelotinib, with achievement of first TSS response by day 29 and continued improvement over time. Improvements favored momelotinib versus danazol for each MFSAF individual item, and greater improvements were observed for disease- and cancer-related fatigue and physical functioning at week 24, with significant results for multiple items/domains across the 3 assessments. These findings are consistent in demonstrating that momelotinib provides substantial symptom benefit.