Mark M. Jones

Ruxolitinib versus Standard Therapy for the Treatment of Polycythemia Vera

BACKGROUND Ruxolitinib, a Janus kinase (JAK) 1 and 2 inhibitor, was shown to have a clinical benefit in patients with polycythemia vera in a phase 2 study. We conducted a phase 3 open-label study to evaluate the efficacy and safety of ruxolitinib versus standard therapy in patients with polycythemia vera who had an inadequate response to or had unacceptable side effects from hydroxyurea. METHODS We randomly assigned phlebotomy-dependent patients with splenomegaly, in a 1:1 ratio, to receive ruxolitinib (110 patients) or standard therapy (112 patients). The primary end point was both hematocrit control through week 32 and at least a 35% reduction in spleen volume at week 32, as assessed by means of imaging. RESULTS The primary end point was achieved in 21% of the patients in the ruxolitinib group versus 1% of those in the standard-therapy group (P<0.001). Hematocrit control was achieved in 60% of patients receiving ruxolitinib and 20% of those receiving standard therapy; 38% and 1% of patients in the two groups, respectively, had at least a 35% reduction in spleen volume. A complete hematologic remission was achieved in 24% of patients in the ruxolitinib group and 9% of those in the standard-therapy group (P=0.003); 49% versus 5% had at least a 50% reduction in the total symptom score at week 32. In the ruxolitinib group, grade 3 or 4 anemia occurred in 2% of patients, and grade 3 or 4 thrombocytopenia occurred in 5%; the corresponding percentages in the standard-therapy group were 0% and 4%. Herpes zoster infection was reported in 6% of patients in the ruxolitinib group and 0% of those in the standard-therapy group (grade 1 or 2 in all cases). Thromboembolic events occurred in one patient receiving ruxolitinib and in six patients receiving standard therapy. CONCLUSIONS In patients who had an inadequate response to or had unacceptable side effects from hydroxyurea, ruxolitinib was superior to standard therapy in controlling the hematocrit, reducing the spleen volume, and improving symptoms associated with polycythemia vera. (Funded by Incyte and others; RESPONSE ClinicalTrials.gov number, NCT01243944.).

Long-term findings from COMFORT-II, a phase 3 study of ruxolitinib vs best available therapy for myelofibrosis

Ruxolitinib is a Janus kinase (JAK) (JAK1/JAK2) inhibitor that has demonstrated superiority over placebo and best available therapy (BAT) in the Controlled Myelofibrosis Study with Oral JAK Inhibitor Treatment (COMFORT) studies. COMFORT-II was a randomized (2:1), open-label phase 3 study in patients with myelofibrosis; patients randomized to BAT could crossover to ruxolitinib upon protocol-defined disease progression or after the primary end point, confounding long-term comparisons. At week 48, 28% (41/146) of patients randomized to ruxolitinib achieved ⩾35% decrease in spleen volume (primary end point) compared with no patients on BAT (P<0.001). Among the 78 patients (53.4%) in the ruxolitinib arm who achieved ⩾35% reductions in spleen volume at any time, the probability of maintaining response was 0.48 (95% confidence interval (CI), 0.35–0.60) at 5 years (median, 3.2 years). Median overall survival was not reached in the ruxolitinib arm and was 4.1 years in the BAT arm. There was a 33% reduction in risk of death with ruxolitinib compared with BAT by intent-to-treat analysis (hazard ratio (HR)=0.67; 95% CI, 0.44–1.02; P=0.06); the crossover-corrected HR was 0.44 (95% CI, 0.18–1.04; P=0.06). There was no unexpected increased incidence of adverse events with longer exposure. This final analysis showed that spleen volume reductions with ruxolitinib were maintained with continued therapy and may be associated with survival benefits.

Ruxolitinib versus best available therapy in patients with Polycythemia Vera: 80 Week follow up from the RESPONSE trial

RESPONSE is an open-label phase 3 study evaluating the Janus kinase 1/Janus kinase 2 inhibitor ruxolitinib versus best available therapy for efficacy/safety in hydroxyurea-resistant or intolerant patients with polycythemia vera. This preplanned analysis occurred when all patients completed the Week 80 visit or discontinued. Objectives included evaluating the durability of the primary response (Week 32 phlebotomy-independent hematocrit control plus ≥35% spleen volume reduction), its components, and that of complete hematologic remission; and long-term safety. Median exposure was 111 weeks; 91/110 (82.7%) patients randomized to ruxolitinib remained on treatment. No patients continued best available therapy (98/112 [87.5%] crossed over to ruxolitinib, most at/soon after Week 32). At Week 32, primary response was achieved by 22.7% vs. 0.9% of patients randomized to ruxolitinib and best available therapy, respectively (hematocrit control, 60.0% vs. 18.8%; spleen response, 40.0% vs. 0.9%). The probability of maintaining primary and hematocrit responses for ≥80 weeks was 92% and 89%, respectively; 43/44 spleen responses were maintained until Week 80. Complete hematologic remission at Week 32 was achieved in 23.6% of ruxolitinib-randomized patients; the probability of maintaining complete hematologic remission for ≥80 weeks was 69%. Among ruxolitinib crossover patients, 79.2% were not phlebotomized, and 18.8% achieved a ≥35% reduction from baseline in spleen volume after 32 weeks of treatment. New or worsening hematologic laboratory abnormalities in ruxolitinib-treated patients were primarily grade 1/2 decreases in hemoglobin, lymphocytes, and platelets. The thromboembolic event rate per 100 patient-years was 1.8 with randomized ruxolitinib treatment vs. 8.2 with best available therapy. These data support ruxolitinib as an effective long-term treatment option for hydroxyurea-resistant or intolerant patients with polycythemia vera. This trial was registered at clinicaltrials.gov identifier: 01243944.

Changes in quality of life and disease-related symptoms in patients with polycythemia vera receiving ruxolitinib or standard therapy

Polycythemia 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.

The efficacy and safety of continued hydroxycarbamide therapy versus switching to ruxolitinib in patients with polycythaemia vera: a randomized, double-blind, double-dummy, symptom study (RELIEF)

The 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.

Association between Treatment Response and Potential Indicators of Efficacy and Safety in a Phase III Trial of Decitabine in Older Patients with Acute Myeloid Leukemia

Objective: In a phase III trial, 485 patients aged 65 years or older with newly diagnosed acute myeloid leukemia received decitabine (20 mg/m2 intravenously for 5 days) or treatment of choice (supportive care or cytarabine 20 mg/m2 subcutaneously for 10 days) every 4 weeks. This post hoc analysis investigated potential efficacy and safety indicators and treatment response. Methods: Transfusions, intravenous antibiotics, and dose modifications were tabulated for responders (morphologic complete remission, complete remission with incomplete blood count recovery, or partial response) and nonresponders. Results: Median overall survival was significantly greater for treatment responders than for nonresponders (17.4 months vs 4.3 months; P<0.0001). Nonresponders had more intravenous antibiotic use (P=0.024), dose modifications per cycle (P=0.016), and platelet or red blood cell transfusions per cycle (P<0.0001). Conclusions: Response to decitabine or to treatment of choice may be associated with certain indicators in older patients with acute myeloid leukemia.

Efficacy and safety of ruxolitinib after and versus interferon use in the RESPONSE studies

Ruxolitinib was well tolerated and superior to best available therapy (including interferon [IFN]) in controlling hematocrit without phlebotomy eligibility, normalizing blood counts, and improving polycythemia vera-related symptoms in the Study of Efficacy and Safety in Polycythemia Vera Subjects Who Are Resistant to or Intolerant of Hydroxyurea: JAK Inhibitor INC424 (INCB018424) Tablets Versus Best Available Care (RESPONSE) studies. This ad hoc analysis focuses on ruxolitinib in relation to IFN in the RESPONSE studies, with attention on the following: (1) safety and efficacy of ruxolitinib and best available therapy in patients who received IFN before study randomization, (2) safety and efficacy of IFN during randomized treatment in best available therapy arm, and (3) use of ruxolitinib after crossover from best available therapy in IFN-treated patients. IFN exposure before randomization had little effect on the efficacy or safety of ruxolitinib. In the randomized treatment arms, ruxolitinib was superior to IFN in efficacy [hematocrit control (RESPONSE = 60% of ruxolitinib vs 23% of IFN patients; RESPONSE-2 = 62% of ruxolitinib vs 15% of IFN patients)] and was tolerated better in hydroxyurea-resistant or hydroxyurea-intolerant patients. After crossing over to receive ruxolitinib, patients who had initially received IFN and did not respond had improved hematologic and spleen responses (62% of patients at any time after crossover) and an overall reduction in phlebotomy procedures. Rates and incidences of the most common adverse events decreased after crossover to ruxolitinib, except for infections (primarily grade 1 or 2). These data suggest that ruxolitinib is efficacious and well tolerated in patients who were previously treated with IFN. The RESPONSE (NCT01243944) and RESPONSE-2 (NCT02038036) studies were registered at clinicaltrials.gov.

Comprehensive haematological control with ruxolitinib in patients with polycythaemia vera resistant to or intolerant of hydroxycarbamide

Additional Supporting Information may be found in the online version of this article: Fig S1. Western blot analysis for KAT8 expression and H4K16 acetylation level in three leukemia cell lines. (B) Realtime PCR analysis for KAT8 mRNA expression during U937 cell line PMA-induced differentiation