A Multicenter Retrospective Noninterventional Follow-up Study in Patients with Sickle Cell Pain Crisis Who Previously Participated in the Sustain Trial in the United States Successor Study

INTRODUCTION

SUSTAIN was a randomized, double-blind, placebo-controlled, phase 2, 52-week study that compared the effect of crizanlizumab, a P-selectin inhibitor, versus placebo on the frequency of sickle cell pain crises (SCPCs, or vaso-occlusive crises [VOCs] leading to a health care visit) in patients with any genotype of sickle cell disease (SCD). Crizanlizumab 5.0 mg/kg significantly reduced the annual frequency of VOCs versus placebo (1.6 vs 3.0, P=0.01) and increased the time to first on-treatment VOC (4.1 vs 1.4 months, P=0.001). The current study, SUCCESSOR (SUSTAIN Chart-review of Crizanlizumab to Evaluate Sickle-cell Study One-year Retrospective), reviewed medical records of patients who completed the SUSTAIN study at US sites to assess additional cases of significant pain crisis events, and to generate real-world data on treatment patterns and health care resource utilization upon completion of treatment with crizanlizumab.

METHODS

SUCCESSOR is a retrospective cohort study of adult patients (≥18 years old) who participated in the SUSTAIN study in the United States to evaluate outcomes related to SCD up to 52 weeks following their completion of the trial. SUCCESSOR included the per protocol population from SUSTAIN, which included the intent-to-treat patients who received at least 12 of the 14 planned study drug doses, completed a visit at least 14 days after the final dose of study drug, and had no major protocol violations that impacted the efficacy assessments. The overall study period for the retrospective study was from September 2015 to March 2017 and patient data were obtained from medical records. Crizanlizumab was not administered post-SUSTAIN. Patient consent was obtained prior to data collection if required by local and/or central research ethics review.

RESULTS

In this preliminary analysis, a total of 6 patient data sets were extracted. These patients had been randomized to the following treatment arms in the SUSTAIN study: 1 placebo, 1 crizanlizumab 2.5 mg/kg, and 4 crizanlizumab 5.0 mg/kg. The patient who had received placebo during SUSTAIN was a 27-year-old male with HbS/β⁰-thalassemia SCD. The patient who had received crizanlizumab 2.5 mg/kg was a 42-year-old female with HbSC SCD. The patients who had received crizanlizumab 5.0 mg/kg were: a 28-year-old male with HbSS SCD; a 32-year-old female with HbSS SCD; a 56-year-old female with HbSC SCD; and a 65-year-old female with HbSS SCD. All patients were Black or African-American. In the 52 weeks following completion of the SUSTAIN study, patients who had received placebo or crizanlizumab 2.5 mg/kg reported 4 and 5 VOC events, respectively, while crizanlizumab 5.0 mg/kg patients reported 0-2 VOC events (Table). Four patients (3 crizanlizumab 5.0 mg/kg, 1 placebo) reported hydroxyurea (HU) usage during and after SUSTAIN. One patient who had received crizanlizumab 5.0 mg/kg and did not report HU usage during SUSTAIN reported HU usage post-SUSTAIN. All patients reported opioid usage after SUSTAIN. Transfusions were not allowed during SUSTAIN; 2 patients, 1 who had received crizanlizumab 5.0 mg/kg and 1 who had received placebo, reported transfusions post-SUSTAIN. Five of the 6 patients reported utilizing health care resources (eg, clinic visits, emergency department visits, or hospitalizations) post-SUSTAIN. One patient who received crizanlizumab 5.0 mg/kg did not report utilizing any health care resources post-SUSTAIN and did not report any VOC events in the 52 weeks after SUSTAIN.

CONCLUSIONS

We report our initial results from a limited number of patients from SUCCESSOR and therefore summarized post-SUSTAIN outcomes without analysis. In 5 of the 6 patients, the annual frequency of VOC events remained the same or increased in the post-SUSTAIN period compared to that during the SUSTAIN study. Data collection is ongoing in additional eligible patients.

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