Roger M. Lyons

This study aimed to describe clinical characteristics-including blood counts and pharmacologic cytoreductive treatment patterns-and outcomes after 6 months of hydroxyurea (HU) treatment among patients with polycythemia vera (PV) in US community practices. This retrospective observational study included adult patients with a PV diagnosis (1JAN2008-31JAN2020) and ≥2 postdiagnosis visits in the iKnowMed electronic health record database (US Oncology Network and non-Network clinics). Suboptimal HU response required ≥1 criterion after ≥3 months of treatment: white blood cell count (WBC) >10 × 10⁹/L, platelet count >400 × 10⁹/L, and/or hematocrit >45%. Patient characteristics were summarized from structured data using descriptive statistics; overall survival was assessed by Kaplan-Meier method. Among 5871 patients, mean age at diagnosis was 66.1 years (69.8% ≥60 years); 67.2, 59.4, 38.2, and 33.9% of patients had elevated hematocrit, hemoglobin, WBC, and platelets, respectively; 6.1% had a previous thrombotic event. Of 4185 (71.3%) high-risk and 1675 low-risk patients, 55.0 and 32.0% received pharmacologic cytoreductive treatment, most commonly HU (89.8 and 88.9%). After 6 months of pharmacologic cytoreductive treatment, 56.9% had a suboptimal response. Five-year survival probability was 81.5 and 84.3% among patients with suboptimal and optimal responses to HU, respectively, which was not statistically different but suggests potential for survival benefits with longer follow-up. Nearly half of high-risk patients with PV did not receive pharmacologic cytoreductive treatment. Of those who did, over half had suboptimal response, suggesting these patients may need dose adjustments, improved adverse effect management, or alternative treatments. Longer follow-up may be needed to assess an association between HU response and survival.

In indolent non-Hodgkin's lymphoma (iNHL), patients treated with rituximab, alone or in combination with various chemotherapeutic agents eventually relapse. This study evaluated the combination of ofatumumab and bendamustine, followed by maintenance ofatumumab in patients with relapsed iNHL with prior sensitivity to rituximab. Among the 49 patients enrolled, 24.5% achieved a complete response (CR) and 42.9% achieved a partial response (PR), with an overall response rate of 67.3% at the end of the induction therapy. Additionally, six patients with PR during induction phase achieved CR during the maintenance phase. Treatment-related adverse event was observed in 95.9% patients. The most common hematologic and biochemical abnormalities were decrease in lymphocytes (85.7%) and increase in glucose (91.8%), respectively. Overall, 42.9% progressed and 14.3% died during the study. Thus, ofatumumab in combination with bendamustine, followed by ofatumumab maintenance, was effective in the treatment of patients with iNHL with a manageable safety profile (NCT01294579).

The randomized, double-blind, placebo-controlled, phase 3 COMFORT-I trial evaluated the JAK1/JAK2 inhibitor ruxolitinib in patients with intermediate-2/high-risk myelofibrosis. The primary and planned 3-year analyses of COMFORT-I data demonstrated that ruxolitinib—the first myelofibrosis-approved therapy—reduced splenomegaly and prolonged overall survival versus placebo. Here, we present the final 5-year results. Patients managed in Australia, Canada, and the USA were randomized centrally (interactive voice response system) 1:1 to oral ruxolitinib twice daily (15 or 20 mg per baseline platelet counts) or placebo. Investigators and patients were blinded to treatment. The secondary endpoints evaluated in this analysis were durability of a ≥35% reduction from baseline in spleen volume (spleen response) and overall survival, evaluated in the intent-to-treat population. Safety was evaluated in patients who received study treatment. Patients were randomized (September 2009–April 2010) to ruxolitinib (n = 155) or placebo (n = 154). At termination, 27.7% of ruxolitinib-randomized patients and 25.2% (28/111) who crossed over from placebo were on treatment; no patients remained on placebo. Patients randomized to ruxolitinib had a median spleen response duration of 168.3 weeks and prolonged median overall survival versus placebo (ruxolitinib group, not reached; placebo group, 200 weeks; HR, 0.69; 95% CI, 0.50–0.96; P = 0.025) despite the crossover to ruxolitinib. The ruxolitinib safety profile remained consistent with previous analyses. The most common new-onset all-grade nonhematologic adverse events starting <12 versus ≥48 months after ruxolitinib initiation were fatigue (29.0 vs 33.3%) and diarrhea (27.8 vs 14.6%). New-onset grade 3 or 4 anemia and thrombocytopenia both primarily occurred within the first 6 months, with no cases after 42 months. The most common treatment-emergent adverse event-related deaths in the ruxolitinib-randomized group were sepsis (2.6%), disease progression (1.9%), and pneumonia (1.9%). The final COMFORT-I results continue to support ruxolitinib as an effective treatment for patients with intermediate-2/high-risk MF. ClinicalTrials.gov, NCT00952289

Lenalidomide treatment in myelodysplastic syndrome (MDS) may lead to thrombocytopenia and dose reductions/delays. This study evaluated the safety and tolerability of the thrombopoietin mimetic romiplostim and its effects on the incidence of clinically significant thrombocytopenic events (CSTEs) in lower risk MDS patients receiving lenalidomide. Patients were assigned to weekly placebo (n = 12) or romiplostim 500 μg (n = 14) or 750 μg (n = 13) for four 28-day lenalidomide cycles. The treatment groups were generally similar with respect to baseline disease characteristics. Del(5q) abnormalities were noted in 1 (8%) patient in the placebo group, 3 (21%) in the romiplostim 500 μg group, and two (15%) in the 750 μg group. CSTEs were noted in 8 (67%) patients in the placebo group, 4 (29%) in the romiplostim 500 μg group, and 8 (62%) in the romiplostim 750 μg group. Throughout the study, median platelet counts trended lower in placebo-treated than in romiplostim-treated patients. Thrombocytopenia-related adjustments in lenalidomide occurred in 6 (50%) patients in the placebo group, 5 (36%) in the romiplostim 500 μg group, and 2 (15%) in the 750 μg group. Although the percentages of patients who received platelet transfusions were similar across treatment groups, there was a trend toward lower numbers of transfusions in both romiplostim groups during each treatment cycle. There were two serious treatment-related adverse events during the treatment period (cerebrovascular accident, placebo; worsening thrombocytopenia, romiplostim 500 μg). Two patients (romiplostim 500 and 750 μg, respectively) had an increase in bone marrow blasts to >20% during treatment, but had no post-treatment biopsy to confirm or exclude the diagnosis of progression to AML. These data suggest that romiplostim administered to MDS patients during lenalidomide treatment may decrease the frequency of dose reductions/delays due to thrombocytopenia. Additional study is needed to confirm the results of this preliminary trial. ClinicalTrials.gov NCT00418665

Abstract 2185

Ezatiostat, a glutathione S-transferase P1-1 inhibitor, promotes the maturation of hematopoietic progenitors and induces apoptosis in cancer cells.