Voxelotor in adolescents and adults with sickle cell disease (HOPE): long-term follow-up results of an international, randomised, double-blind, placebo-controlled, phase 3 trial
The Lancet. Haematology. 2021
BACKGROUND For decades, patients with sickle cell disease have had only a limited number of therapies available. In 2019, voxelotor (1500 mg), an oral once-daily sickle haemoglobin polymerisation inhibitor, was approved in the USA for the treatment of sickle cell disease in patients aged 12 years and older on the basis of HOPE trial data. To further describe the applicability of voxelotor as a treatment for this chronic illness, we report the long-term efficacy and safety of this drug at 72 weeks of treatment; the conclusion of the placebo-controlled HOPE trial. METHODS HOPE is an international, randomised, double-blind, placebo-controlled, phase 3 trial done at 60 clinical sites in Canada, Egypt, France, Italy, Jamaica, Kenya, Lebanon, Netherlands, Oman, Turkey, the USA, and the UK. Patients (aged 12-65 years) with confirmed sickle cell disease, a haemoglobin concentration of 5·5-10·5 g/dL at enrolment, and who had between one and ten vaso-occlusive crisis events in the previous 12 months were enrolled. Patients receiving regularly scheduled transfusion therapy, who had received a transfusion in the previous 60 days, or who had been admitted to hospital for a vaso-occlusive crisis in the previous 14 days were excluded. Patients were randomly assigned (1:1:1) to receive either once-daily oral voxelotor 1500 mg, voxelotor 900 mg, or placebo for 72 weeks. Randomisation was done centrally by use of an interactive web response system, stratified by baseline hydroxyurea use (yes vs no), age group (adolescents [12 to <18 years] vs adults [18 to 65 years]), and geographic region (North America vs Europe vs other). The primary endpoint (already reported) was the proportion of patients who achieved a haemoglobin response at week 24. In this final analysis, we report prespecified long-term efficacy assessments by intention to treat, including changes in haemoglobin concentrations from baseline to week 72, changes in the concentration of haemolysis markers (absolute and percentage reticulocytes, indirect bilirubin concentrations, and lactate dehydrogenase concentrations) from baseline to week 72, the annualised incidence of vaso-occlusive crises, and patient functioning, as assessed with the Clinical Global Impression of Change (CGI-C) scale. Safety was assessed in patients who received at least one dose of treatment (modified intention-to-treat population). This trial is registered with ClinicalTrials.gov, NCT03036813. FINDINGS Between Dec 5, 2016, and May 3, 2018, 449 patients were screened, of whom 274 were randomly assigned to the voxelotor 1500 mg group (n=90), the voxelotor 900 mg group (n=92), or the placebo group (n=92). At week 72, the adjusted mean change in haemoglobin concentration from baseline was 1·0 g/dL (95% CI 0·7 to -1·3) in the voxelotor 1500 mg group, 0·5 g/dL (0·3 to -0·8) in the voxelotor 900 mg group, and 0·0 g/dL (-0·3 to 0·3) in the placebo group, with a significant difference observed between the voxelotor 1500 mg group and the placebo group (p<0·0001), and between the voxelotor 900 mg group and the placebo group (p=0·014). Significant improvements in markers of haemolysis, as assessed by the difference in adjusted mean percentage change from baseline at week 72 versus placebo, were observed in the voxelotor 1500 mg group in indirect bilirubin concentrations (-26·6% [95% CI -40·2 to -12·9]) and percentage of reticulocytes (-18·6% [-33·9 to -3·3]). The proportion of patients in the voxelotor 1500 mg group who were rated as "moderately improved" or "very much improved" at week 72 with the CGI-C was significantly greater than in the placebo group (39 [74%] of 53 vs 24 [47%] of 51; p=0·0057). Serious adverse events unrelated to sickle cell disease were reported in 25 (28%) of 88 patients in the voxelotor 1500 mg group, 20 (22%) of 92 patients in the voxelotor 900 mg group, and 23 (25%) of 91 patients in the placebo group. Grade 3 or 4 adverse events were infrequent (ie, occurred in <10% of patients); anaemia occurred in five or more patients (two [2%] patients in the voxelotor 1500 mg group, seven [8%] patients in the voxelotor 900 mg group, and three [3%] patients in the placebo group). Of all 274 patients, six (2%) deaths occurred during the study (two deaths in each treatment group), all of which were judged as unrelated to treatment. INTERPRETATION Voxelotor 1500 mg resulted in rapid and durable improvements in haemoglobin concentrations maintained over 72 weeks and has potential to address the substantial morbidity associated with haemolytic anaemia in sickle cell disease. FUNDING Global Blood Therapeutics.
Evaluation of the efficacy and safety of deferiprone compared with deferasirox in paediatric patients with transfusion-dependent haemoglobinopathies (DEEP-2): a multicentre, randomised, open-label, non-inferiority, phase 3 trial
Lancet Haematol. 2020;7(6):e469-e478
BACKGROUND Transfusion-dependent haemoglobinopathies require lifelong iron chelation therapy with one of the three iron chelators (deferiprone, deferasirox, or deferoxamine). Deferasirox and deferiprone are the only two oral chelators used in adult patients with transfusion-dependent haemoglobinopathies. To our knowledge, there are no randomised clinical trials comparing deferiprone, a less expensive iron chelator, with deferasirox in paediatric patients. We aimed to show the non-inferiority of deferiprone versus deferasirox. METHODS DEEP-2 was a phase 3, multicentre, randomised trial in paediatric patients (aged 1 month to 18 years) with transfusion-dependent haemoglobinopathies. The study was done in 21 research hospitals and universities in Italy, Egypt, Greece, Albania, Cyprus, Tunisia, and the UK. Participants were receiving at least 150 mL/kg per year of red blood cells for the past 2 years at the time of enrolment, and were receiving deferoxamine (<100 mg/kg per day) or deferasirox (<40 mg/kg per day; deferasirox is not registered for use in children aged <2 years so only deferoxamine was being used in these patients). Any previous chelation treatment was permitted with a 7-day washout period. Patients were randomly assigned 1:1 to receive orally administered daily deferiprone (75-100 mg/kg per day) or daily deferasirox (20-40 mg/kg per day) administered as dispersible tablets, both with dose adjustment for 12 months, stratified by age (<10 years and ≥10 years) and balanced by country. The primary efficacy endpoint was based on predefined success criteria for changes in serum ferritin concentration (all patients) and cardiac MRI T2-star (T2*; patients aged >10 years) to show non-inferiority of deferiprone versus deferasirox in the per-protocol population, defined as all randomly assigned patients who received the study drugs and had available data for both variables at baseline and after 1 year of treatment, without major protocol violations. Non-inferiority was based on the two-sided 95% CI of the difference in the proportion of patients with treatment success between the two groups and was shown if the lower limit of the two-sided 95% CI was greater than -12.5%. Safety was assessed in all patients who received at least one dose of study drug. This study is registered with EudraCT, 2012-000353-31, and ClinicalTrials.gov, NCT01825512. FINDINGS 435 patients were enrolled between March 17, 2014, and June 16, 2016, 393 of whom were randomly assigned to a treatment group (194 to the deferiprone group; 199 to the deferasirox group). 352 (90%) of 390 patients had beta-thalassaemia major, 27 (7%) had sickle cell disease, five (1%) had thalassodrepanocytosis, and six (2%) had other haemoglobinopathies. Median follow-up was 379 days (IQR 294-392) for deferiprone and 381 days (350-392) for deferasirox. Non-inferiority of deferiprone versus deferasirox was established (treatment success in 69 [55.2%] of 125 patients assigned deferiprone with primary composite efficacy endpoint data available at baseline and 1 year vs 80 [54.8%] of 146 assigned deferasirox, difference 0.4%; 95% CI -11.9 to 12.6). No significant difference between the groups was shown in the occurrence of serious and drug-related adverse events. Three (2%) cases of reversible agranulocytosis occurred in the 193 patients in the safety analysis in the deferiprone group and two (1%) cases of reversible renal and urinary disorders (one case of each) occurred in the 197 patients in the deferasirox group. Compliance was similar between treatment groups: 183 (95%) of 193 patients in the deferiprone group versus 192 (97%) of 197 patients in the deferisirox group. INTERPRETATION In paediatric patients with transfusion-dependent haemoglobinopathies, deferiprone was effective and safe in inducing control of iron overload during 12 months of treatment. Considering the need for availability of more chelation treatments in paediatric populations, deferiprone offers a valuable treatment option for this age group. FUNDING EU Seventh Framework Programme.
A Phase 3 Randomized Trial of Voxelotor in Sickle Cell Disease
Paediatric patients with transfusion-dependent haemoglobinopathies enrolled in the DEEP-2 multicentre randomised trial (n=393).
Daily deferiprone (75-100 mg/kg per day) (n=194).
Daily deferasirox (20-40 mg/kg per day) (n=199).
Non-inferiority of deferiprone versus deferasirox was established (treatment success in 55.2% patients assigned deferiprone with primary composite efficacy endpoint data available at baseline and 1 year vs. 54.8% assigned deferasirox). No significant difference between the groups was shown in the occurrence of serious and drug-related adverse events. Compliance was similar between treatment groups: 95% of patients in the deferiprone group versus 97% of patients in the deferasirox group.
The New England journal of medicine. 2019
BACKGROUND Deoxygenated sickle hemoglobin (HbS) polymerization drives the pathophysiology of sickle cell disease. Therefore, direct inhibition of HbS polymerization has potential to favorably modify disease outcomes. Voxelotor is an HbS polymerization inhibitor. METHODS In a multicenter, phase 3, double-blind, randomized, placebo-controlled trial, we compared the efficacy and safety of two dose levels of voxelotor (1500 mg and 900 mg, administered orally once daily) with placebo in persons with sickle cell disease. The primary end point was the percentage of participants who had a hemoglobin response, which was defined as an increase of more than 1.0 g per deciliter from baseline at week 24 in the intention-to-treat analysis. RESULTS A total of 274 participants were randomly assigned in a 1:1:1 ratio to receive a once-daily oral dose of 1500 mg of voxelotor, 900 mg of voxelotor, or placebo. Most participants had sickle cell anemia (homozygous hemoglobin S or hemoglobin Sbeta(0)-thalassemia), and approximately two thirds were receiving hydroxyurea at baseline. In the intention-to-treat analysis, a significantly higher percentage of participants had a hemoglobin response in the 1500-mg voxelotor group (51%; 95% confidence interval [CI], 41 to 61) than in the placebo group (7%; 95% CI, 1 to 12). Anemia worsened between baseline and week 24 in fewer participants in each voxelotor dose group than in those receiving placebo. At week 24, the 1500-mg voxelotor group had significantly greater reductions from baseline in the indirect bilirubin level and percentage of reticulocytes than the placebo group. The percentage of participants with an adverse event that occurred or worsened during the treatment period was similar across the trial groups. Adverse events of at least grade 3 occurred in 26% of the participants in the 1500-mg voxelotor group, 23% in the 900-mg voxelotor group, and 26% in the placebo group. Most adverse events were not related to the trial drug or placebo, as determined by the investigators. CONCLUSIONS In this phase 3 randomized, placebo-controlled trial involving participants with sickle cell disease, voxelotor significantly increased hemoglobin levels and reduced markers of hemolysis. These findings are consistent with inhibition of HbS polymerization and indicate a disease-modifying potential. (Funded by Global Blood Therapeutics; HOPE ClinicalTrials.gov number, NCT03036813.).