Verstovsek, Srdan

Abstract Allogeneic hematopoietic cell transplantation (HCT) is the only curative therapy for myelofibrosis (MF). In this large multicenter retrospective study, overall survival (OS) in MF patients treated with allogeneic HCT (551 patients) and without HCT (non-HCT) (1377 patients) was analyzed with Cox proportional hazards model. Survival analysis stratified by the Dynamic International Prognostic Scoring System (DIPSS) revealed that the first year of treatment arm assignment, due to upfront risk of transplant-related mortality (TRM), HCT was associated with inferior OS compared with non-HCT (non-HCT vs HCT: DIPSS intermediate 1 [Int-1]: hazard ratio [HR] = 0.26, P < .0001; DIPSS-Int-2 and higher: HR, 0.39, P < .0001). Similarly, in the DIPSS low-risk MF group, due to upfront TRM risk, OS was superior with non-HCT therapies compared with HCT in the first-year post treatment arm assignment (HR, 0.16, P = .006). However, after 1 year, OS was not significantly different (HR, 1.38, P = .451). Beyond 1 year of treatment arm assignment, an OS advantage with HCT therapy in Int-1 and higher DIPSS score patients was observed (non-HCT vs HCT: DIPSS-Int-1: HR, 2.64, P < .0001; DIPSS-Int-2 and higher: HR, 2.55, P < .0001). In conclusion, long-term OS advantage with HCT was observed for patients with Int-1 or higher risk MF, but at the cost of early TRM. The magnitude of OS benefit with HCT increased as DIPSS risk score increased and became apparent with longer follow-up.

AimsRearrangement of the platelet‐derived growth factor receptor B (PDGFRB) gene defines a unique group of myeloid/lymphoid neoplasms with frequent eosinophilia and high sensitivity to tyrosine kinase inhibitors. This genetic abnormality is also rarely reported in Philadelphia‐like B‐cell acute lymphoblastic leukaemia/lymphoma (B‐ALL). PDGFRB rearrangement was initially thought to only occur in cases with 5q31–33 rearrangement as determined with conventional cytogenetics; however, there are reported cases with cryptic rearrangements. We aim to develop a broader strategy for screening of PDGFRB rearrangements of patients with myeloid/lymphoid neoplasms.Methods and resultsWe performed fluorescence in‐situ hybridisation (FISH) for PDGFRB rearrangement in 197 patients, including 70 with B‐ALL, 10 with myeloid neoplasms with 5q31–33 rearrangements, and 117 with eosinophilia (≥0.5 × 109/l in peripheral blood or ≥5% in bone marrow), and identified PDGFRB rearrangement in four of 197 (2.0%) cases. In an attempt to identify clinicopathological and genetic features that may have a stronger association with PDGFRB rearrangement, we analysed 13 patients with confirmed PDGFRB rearrangements, including 10 with myeloid neoplasms and three with B‐ALL. Among the 10 patients with myeloid neoplasms, eosinophilia was present in eight, monocytosis in two, 5q31–33 rearrangement in seven, and abnormal bone marrow morphology in all. All patients with myeloid neoplasms showed an excellent response to imatinib, including a patient in blast crisis. The three B‐ALL patients presented de novo, showed no eosinophilia, had a complex karyotype including 5q31–33 rearrangement, and had clinically aggressive courses with ultimate patient demise.ConclusionsThese findings suggest that a higher yield for the identification of PDGFRB rearrangement may result from an index of suspicion in patients with eosinophilia, monocytosis, bone marrow features of a myeloid neoplasm, and 5q31–33 rearrangement, and patients with Philadelphia‐like B‐ALL.

SummarySimtuzumab, a monoclonal antibody inhibitor of extracellular matrix enzyme lysyl oxidase‐like‐2, showed preclinical promise and was well tolerated in clinical studies. A phase 2, open‐label study of simtuzumab was conducted in patients with primary myelofibrosis (MF), post‐polycythaemia vera MF and post‐essential thrombocythaemia MF. Fifty‐four patients were randomized to receive simtuzumab alone (200 or 700 mg [n = 12 each group]) or simtuzumab (200 or 700 mg) with ruxolitinib (n = 15 each group) for 24 weeks. Simtuzumab alone or in combination with ruxolitinib showed no clinical benefit at 24 weeks. The mean serum simtuzumab trough concentrations appeared to increase dose‐proportionally between the 200‐mg and 700‐mg treatment groups. Therapy‐related serious adverse events were pyrexia, pain in extremity (both in 1 patient) and infusion reaction (in another patient). Bone marrow fibrosis (BMF) score was reduced at 24 weeks in 2 patients (16·7%) in the simtuzumab 700‐mg group, 1 (6·7%) in the simtuzumab 200‐mg + ruxolitinib group, and 2 (13·3%) in the simtuzumab 700‐mg + ruxolitinib group; similar numbers of patients had increased BMF. Simtuzumab alone or with ruxolitinib was well tolerated but did not produce clinical benefit nor consistently reduce BMF in patients with MF by 24 weeks.

SummaryThe randomized, double‐blind, double‐dummy, phase 3b RELIEF trial evaluated polycythaemia vera (PV)‐related symptoms in patients who were well controlled with a stable dose of hydroxycarbamide (also termed hydroxyurea) but reported PV‐related symptoms. Patients were randomized 1:1 to ruxolitinib 10 mg BID (n = 54) or hydroxycarbamide (prerandomization dose/schedule; n = 56); crossover to ruxolitinib was permitted after Week 16. The primary endpoint, ≥50% improvement from baseline in myeloproliferative neoplasm ‐symptom assessment form total symptom score cytokine symptom cluster (TSS‐C; sum of tiredness, itching, muscle aches, night sweats, and sweats while awake) at Week 16, was achieved by 43·4% vs. 29·6% of ruxolitinib‐ and hydroxycarbamide‐treated patients, respectively (odds ratio, 1·82; 95% confidence interval, 0·82–4·04; P = 0·139). The primary endpoint was achieved by 34% of a subgroup who maintained their hydroxycarbamide dose from baseline to Weeks 13–16. In a post hoc analysis, the primary endpoint was achieved by more patients with stable screening‐to‐baseline TSS‐C scores (ratio ≤ 2) receiving ruxolitinib than hydroxycarbamide (47·4% vs. 25·0%; P = 0·0346). Ruxolitinib treatment after unblinding was associated with continued symptom score improvements. Adverse events were primarily grades 1/2 with no unexpected safety signals. Ruxolitinib was associated with a nonsignificant trend towards improved PV‐related symptoms versus hydroxycarbamide, although an unexpectedly large proportion of patients who maintained their hydroxycarbamide dose reported symptom improvement.

AbstractObjectivesPolycythemia vera (PV)‐related symptoms may not be adequately controlled with conventional therapy. This current analysis of the RESPONSE trial evaluated the effects of ruxolitinib compared with standard therapy on quality of life (QoL) and symptoms in patients with PV who were hydroxyurea resistant/intolerant.MethodsIn the previously reported primary analysis, ruxolitinib achieved the primary composite endpoint of hematocrit control and ≥35% reduction in spleen volume at Week 32. The current analysis evaluated patient‐reported outcomes using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire‐Core 30 (EORTC QLQ‐C30), the Myeloproliferative Neoplasm Symptom Assessment Form (MPN‐SAF), the Pruritus Symptom Impact Scale (PSIS), and the Patient Global Impression of Change (PGIC).ResultsCompared with standard therapy, ruxolitinib was associated with greater improvements in global health status/QoL, functional subscales, and individual symptom scores of the EORTC QLQ‐C30. At Week 32, more patients in the ruxolitinib arm (44%) achieved a ≥10‐point improvement in global health status/QoL vs. standard therapy (9%). Improvements in MPN‐SAF symptom scores were consistent with improvements in EORTC QLQ‐C30, PSIS, and PGIC scores.ConclusionsRuxolitinib provides clinically relevant improvements in QoL and ameliorates symptom burden in patients with PV who are hydroxyurea resistant/intolerant.

Key Points Treatment response criteria for MF must capture drug benefit in terms of symptom burden. The current document includes stricter definitions of red cell transfusion need and independence.

Key Points Evidence exists that ELN criteria for response in ET and PV issued in 2009 do not provide relevant measures of benefit for patients. Revised recommendations for assessing response are provided.

SummaryMyelofibrosis (MF) patients can present with a wide spectrum of disease characteristics. We analysed the consistency of ruxolitinib efficacy across patient subgroups in the COntrolled MyeloFibrosis Study With ORal JAK Inhibitor Treatment (COMFORT‐I,) a double‐blind trial, where patients with intermediate‐2 or high‐risk MF were randomized to twice‐daily oral ruxolitinib (n = 155) or placebo (n = 154). Subgroups analysed included MF subtype (primary, post‐polycythaemia vera, post‐essential thrombocythaemia), age (≤65, > 65 years), International Prognostic Scoring System risk group, baseline Eastern Cooperative Oncology Group performance status (0, 1, ≥2), JAK2 V617F mutation (positive, negative), baseline haemoglobin level (≥100, <100 g/l), baseline platelet count (100–200 × 109/l, >200 × 109/l), baseline palpable spleen size (≤10, >10 cm), and baseline quartile of spleen volume and Total Symptom Score (TSS; Q1 = lowest, Q4 = highest). Mean percentage change from baseline to week 24 in spleen volume and TSS were calculated for ruxolitinib and placebo in each subgroup. Overall survival was estimated by Kaplan–Meier method according to original randomization group. In ruxolitinib‐treated patients, reductions in spleen volume and TSS and evidence of improved survival relative to placebo across subgroups were consistent with those seen in the COMFORT‐I population, confirming that ruxolitinib is an effective therapy for the spectrum of MF patients studied in COMFORT‐I.