Persistent leukocytosis in polycythemia vera is associated with disease evolution but not thrombosis.

There are unresolved questions regarding the association between persistent leukocytosis and risk of thrombosis and disease evolution in polycythemia vera (PV), as much of the published literature on the topic does not appropriately use repeated-measures data or time-dependent modeling to answer these questions. To address this knowledge gap, we analyzed a retrospective database of 520 PV patients seen at 10 academic institutions across the United States. Taking hematologic laboratory data at ∼3-month intervals (or as available) for all patients for duration of follow-up, we used group-based trajectory modeling to identify latent clusters of patients who follow distinct trajectories with regard to their leukocyte, hematocrit, and platelet counts over time. We then tested the association between trajectory membership and hazard of 2 major outcomes: thrombosis and disease evolution to myelofibrosis, myelodysplastic syndrome, or acute myeloid leukemia. Controlling for relevant covariates, we found that persistently elevated leukocyte trajectories were not associated with the hazard of a thrombotic event (P = .4163), but were significantly associated with increased hazard of disease evolution in an ascending stepwise manner (overall P = .0002). In addition, we found that neither hematocrit nor platelet count was significantly associated with the hazard of thrombosis or disease evolution.

Real-World Outcomes of Ruxolitinib Treatment for Polycythemia Vera.

INTRODUCTION: Ruxolitinib is approved for the treatment of polycythemia vera (PV) with hydroxyurea resistance or intolerance. Approval was based on the phase III RESPONSE trial, which demonstrated efficacy in a highly selected patient population. MATERIALS AND METHODS: To characterize the tolerability and outcomes of ruxolitinib outside of a clinical trial, we performed a multi-center retrospective analysis of patients with PV treated with ruxolitinib at 11 participating sites across the United States. Outcomes of interest included change in phlebotomy requirements after starting ruxolitinib and spleen response, as these were included in the primary composite outcome in the RESPONSE trial. RESULTS: One hundred twenty-six patients met eligibility criteria, and the median duration of follow-up was 22.4 months (range, 0-63.0 months). At 32 weeks after starting ruxolitinib, the percentage of patients who received at least 1 phlebotomy was significantly decreased compared with before ruxolitinib (37% vs. 56%; relative risk [RR], 0.66; 95% confidence interval [CI], 0.52-0.84; P < .001). Phlebotomy requirements were similarly decreased in patients who had received at least 3 phlebotomies prior to ruxolitinib initiation (28% vs. 17%; RR, 1.65; 95% CI, 1.13-2.40; P < .01). Resolution of palpable splenomegaly was also documented (48% vs. 20%; RR, 2.45; 95% CI, 1.70-3.53; P < .0001). A total of 9.5% of patients discontinued ruxolitinib owing to treatment-emergent adverse events, and 81.7% of patients were receiving ruxolitinib at last known follow-up. CONCLUSION: These real-world results are similar to those reported from the RESPONSE trial, although additional follow-up is necessary to assess long-term outcomes and potential for late-onset toxicity.

A 19-Year-Old College Student With Headache, Photophobia, and Flulike Illness.

CASE PRESENTATION: A 19-year-old previously healthy man presented, minimally responsive, in respiratory distress to an ED after a 2-week history of headache, photophobia, and neck stiffness. Associated symptoms included low-grade fevers, malaise, and dark urine. He had no recent travel, ill contacts, consumption of undercooked meat, new sexual contacts, or illicit drug use. The patient resided in a campus dormitory and did not consume alcohol or tobacco.