Effect of crizanlizumab on pain crises in subgroups of patients with sickle cell disease: A SUSTAIN study analysis.

The cell adhesion molecule P-selectin plays a key role in the pathogenesis of a vaso-occlusive crisis (VOC) in patients with sickle cell disease (SCD). In the double-blind, placebo-controlled phase 2 SUSTAIN study, crizanlizumab (humanized, anti-P-selectin monoclonal antibody) 5 mg/kg significantly lowered the rate of VOC in patients with SCD by 45% vs placebo. In SUSTAIN, patients with SCD were randomized to crizanlizumab 2.5 mg/kg, crizanlizumab 5 mg/kg, or placebo intravenously 14 times over 52 weeks. The primary endpoint was the annual rate of VOC with crizanlizumab vs placebo. This post hoc descriptive analysis evaluated the proportion of patients who did not experience a VOC during the study in the following subgroups: VOCs in the year prior to study entry (2-4/5-10), SCD genotype (HbSS/non-HbSS), and concomitant hydroxyurea use (yes/no). More patients were VOC event-free in the crizanlizumab 5 mg/kg arm than in the placebo arm, including those with more frequent prior VOCs (ie, 5-10; 28.0% vs 4.2%), the HbSS genotype (31.9% vs 17.0%) and/or using concomitant hydroxyurea (33.3% vs 17.5%). Further analyses of secondary endpoints demonstrated that crizanlizumab treatment significantly increased time-to-first VOC vs placebo in these subgroups. The rates of treatment-emergent adverse events were similar between treatment arms across all subgroups. This post hoc analysis of SUSTAIN shows that in patients with a high number of prior VOCs, on concomitant hydroxyurea and/or with the HbSS genotype, crizanlizumab treatment increases the likelihood of patients being VOC event-free and delays time-to-first VOC.

Effect of deferasirox + erythropoietin vs erythropoietin on erythroid response in Low/Int-1-risk MDS patients: Results of the phase II KALLISTO trial.

OBJECTIVES: Erythropoiesis-stimulating agents (ESAs) remain first-choice to treat symptomatic anemia and delay transfusion dependence in most patients with lower-risk myelodysplastic syndromes (MDS) without del(5q). Deferasirox increased erythroid responses in some lower-risk MDS patients in clinical trials, and adding low-dose deferasirox to ESA treatment may further improve erythroid response. METHODS: KALLISTO (NCT01868477) was a randomized, open-label, multicenter, phase II study. Lower-risk MDS patients received deferasirox at 10 mg/kg/d (dispersible tablets) or 7 mg/kg/d (film-coated tablets) plus erythropoietin (n = 11), or erythropoietin alone (n = 12) for 24 weeks. The primary endpoint was the between-group difference in erythroid response within 12 weeks. RESULTS: Erythroid response occurred in 27.3% of patients receiving deferasirox plus erythropoietin vs 41.7% of patients receiving erythropoietin alone within 12 weeks (difference 14.4%; 95% CI -24.0, 48.16). Within 24 weeks, the hematologic response rate was 27.3% with deferasirox plus erythropoietin vs 50% with erythropoietin alone, and hematologic improvement rates were 45.5% vs 100%. Deferasirox plus erythropoietin was generally well tolerated. CONCLUSIONS: In this small pilot study, combining low-dose deferasirox with erythropoietin did not improve erythroid response. It remains of interest to investigate early chelation approaches with even lower deferasirox doses plus erythropoietin in lower-risk MDS patients before the onset of transfusion dependence.

Long-term safety and efficacy of deferasirox in young pediatric patients with transfusional hemosiderosis: Results from a 5-year observational study (ENTRUST).

BACKGROUND: Children with red blood cell disorders may receive regular transfusions from an early age and consequently accumulate iron. Adequate iron chelation therapy can prevent organ damage and delayed growth/development. Deferasirox is indicated for treatment of pediatric patients with chronic iron overload due to transfusional hemosiderosis; however, fewer than 10% of patients in the registration studies were aged 2 to less than 6 years. PROCEDURE: Deferasirox, a once-daily oral iron chelator, was evaluated in young pediatric patients with transfusional hemosiderosis during the observational 5-year ENTRUST study. Patients aged 2 to less than 6 years at enrollment received deferasirox according to local prescribing information, with the primary objective of evaluating safety, specifically renal and hepatic function. Serum ferritin was observed as a surrogate efficacy parameter. RESULTS: In total, 267 patients (mean age 3.2 years) predominantly with ß-thalassemia (n = 176, 65.9%) were enrolled. Mean ± standard deviation deferasirox dose was 25.8 ± 6.5 mg/kg per day over a median of 59.9 months. A total of 145 patients (54.3%) completed 5 years' treatment. The proportion of patients with two or more consecutive postbaseline measurements (≥7 days apart) of serum creatinine higher than age-adjusted upper limit of normal (ULN) and alanine aminotransferase more than five times the ULN was 4.4% (95% confidence interval [CI]: 2.1-7.9) and 4.0% (95% CI: 1.8-7.4), respectively. Median serum ferritin decreased from 1,702 ng/ml at baseline to 1,127 ng/ml at 5 years. There were no new safety signals. CONCLUSIONS: Safety and efficacy of deferasirox in young pediatric patients in this long-term, observational study in everyday clinical practice were consistent with the known deferasirox profile.

Preclinical studies on the use of a P-selectin-blocking monoclonal antibody to halt progression of myelofibrosis in the Gata1low mouse model.

The bone marrow (BM) and spleen from patients with myelofibrosis (MF), as well as those from the Gata1low mouse model of the disease contain increased number of abnormal megakaryocytes. These cells express high levels of the adhesion receptor P-selectin on their surface, which triggers a pathologic neutrophil emperipolesis, leading to increased bioavailability of transforming growth factor-ß (TGF-ß) in the microenvironment and disease progression. With age, Gata1low mice develop a phenotype similar to that of patients with MF, which is the most severe of the Philadelphia-negative myeloproliferative neoplasms. We previously demonstrated that Gata1low mice lacking the P-selectin gene do not develop MF. In the current study, we tested the hypothesis that pharmacologic inhibition of P-selectin may normalize the phenotype of Gata1low mice that have already developed MF. To test this hypothesis, we have investigated the phenotype expressed by aged Gata1low mice treated with the antimouse monoclonal antibody RB40.34, alone and also in combination with ruxolitinib. The results indicated that RB40.34 in combination with ruxolitinib normalizes the phenotype of Gata1low mice with limited toxicity by reducing fibrosis and the content of TGF-ß and CXCL1 (two drivers of fibrosis in this model) in the BM and spleen and by restoring hematopoiesis in the BM and the architecture of the spleen. In conclusion, we provide preclinical evidence that treatment with an antibody against P-selectin in combination with ruxolitinib may be more effective than ruxolitinib alone to treat MF in patients.

International sentinel site surveillance of patients with transfusional hemosiderosis treated with deferasirox in actual practice setting.

OBJECTIVE: The study evaluates the long-term deferasirox treatment of adult and pediatric patients with chronic transfusional iron overload in clinical practice. METHODS: In this non-interventional study, patients were observed for up to 3 years from initiation of deferasirox treatment both prospectively and retrospectively for up to 1 year prior to enrollment. The primary end points were the proportion of patients with ≥1 notable increase in serum creatinine (SCr), and ≥1 notable increase in alanine aminotransferase (ALT). RESULTS: Overall, 120 patients were enrolled and 51 completed the study, with a limited 3-year dropout rate of 12.5% due to adverse events (AEs). Increase in SCr > 33% above baseline and the age-adjusted ULN (upper limit of normal) was observed in 14 patients (95%CI, 7.1-19.2). The ALT levels >5 × ULN was observed in 1 patient. Most frequent AEs reported during treatment with deferasirox include gastrointestinal disturbances. CONCLUSIONS: The long-term treatment with deferasirox was manageable in most transfusion-dependent patients with no unexpected safety findings. Regular monitoring and an adjusted deferasirox dosing strategy per local labels allowed continued iron chelation treatment and control of transfusional iron in the majority of patients on study.