Press Release
GBT Announces Positive Top-line Data from Part A of the Phase 3 HOPE Study of Voxelotor in Sickle Cell Disease
Primary Endpoint Achieved; 58 Percent of Patients on Voxelotor Dosed with 1500 mg at Week 12 Exceeded 1 g/dL Increase in Hemoglobin Versus 9 Percent of Placebo (p<0.0001)
Company Met with
Numerically Fewer Vaso-occlusive Crisis (VOC) Episodes in Each Voxelotor Arm Versus Placebo
GBT to Host Conference Call and Webcast Today,
“Given the well-established association between chronic hemolytic anemia and SCD-related morbidity and mortality, we believe the clinically meaningful increase in hemoglobin and improvement in hemolysis together with the safety profile demonstrated in Part A are highly encouraging,” said
HOPE Study Part A Data
Results from the Part A analysis in 154 patients showed the following:
Efficacy and Safety
- 58 percent of patients taking the 1500 mg dose (p<0.0001) and 38 percent of patients taking the 900 mg dose (p=0.0021) achieved a greater than 1 g/dL increase in hemoglobin at 12 weeks versus 9 percent of patients taking placebo. This compares favorably to the hemoglobin increase assumption agreed to with the
U.S. Food and Drug Administration (FDA ) in the HOPE Study protocol of a 35 percent response. - Statistically significant and dose-dependent improvements in hemoglobin, reticulocytes and bilirubin occurred with both voxelotor doses, further demonstrating an improvement in hemolytic anemia.
- Improvements in these clinical measures of anemia and hemolysis were similar in patients with or without background use of hydroxyurea. Approximately 64 percent of patients enrolled in Part A are on background use of hydroxyurea.
- There were numerically fewer VOC episodes in both voxelotor groups than in the placebo group, which as anticipated did not reach statistical significance due to limited patient follow-up.
- The patient reported outcomes (PRO) data were difficult to interpret due to low baseline symptom scores and high inter-subject and intra-subject variability. Given this, GBT does not plan to utilize the PRO as a key secondary endpoint.
- Voxelotor was generally safe and well tolerated with similar safety profiles between the two doses. There was no evidence of tissue hypoxia at either dose.
The independent Data and Safety Monitoring Board (DSMB) completed its most recent clinical safety review in
GBT plans to present results from Part A at a medical meeting later this year.
Based on the positive Part A results and ongoing regulatory discussions, GBT continues to dose Part A patients, plus approximately 100 additional patients across all three treatment arms, to gather more data. At this time, GBT does not plan additional enrollment until it completes discussions with the
“The pathophysiology and morbidity associated with SCD result from two distinct pathways: hemolytic anemia and vaso-occlusion. New therapies that address each pathway are important and desperately needed,” said
Investor Conference Call and Webcast Details
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About the HOPE Study
The HOPE Study is a randomized, double-blind, placebo-controlled, multi-national study that enrolled patients age 12 and older with SCD who had had at least one episode of VOC in the previous year. The study was originally designed in two parts: Part A compared voxelotor administered at doses of 900 or 1500 mg per day versus placebo in 154 patients treated for at least 12 weeks, and Part B planned to enroll 250 patients randomized to placebo or a dose of voxelotor selected from Part A. The main objectives of Part A were to select the optimal dose, define the first rank secondary endpoint for Part B, and qualify the patient-reported outcome (PRO) instrument. The primary efficacy endpoint is the proportion of patients who achieve a greater than 1 g/dL increase in hemoglobin at 24 weeks of treatment compared with baseline. Key secondary efficacy endpoints evaluated in Part A were the effect of voxelotor on SCD symptom exacerbation as measured by the PRO instrument, overall SCD symptoms as measured by the PRO instrument, and traditionally defined VOCs.
About Accelerated Approval
The
About Sickle Cell Disease
SCD is a lifelong inherited blood disorder caused by a genetic mutation in the beta-chain of hemoglobin, which leads to the formation of abnormal hemoglobin known as sickle hemoglobin (HbS). In its deoxygenated state, HbS has a propensity to polymerize, or bind together, forming long, rigid rods within a red blood cell (
About Voxelotor in Sickle Cell Disease
Voxelotor (previously called GBT440) is being developed as an oral, once-daily therapy for patients with SCD. Voxelotor works by increasing hemoglobin's affinity for oxygen. Since oxygenated sickle hemoglobin does not polymerize, GBT believes voxelotor blocks polymerization and the resultant sickling of red blood cells. With the potential to improve hemolytic anemia and oxygen delivery, GBT believes that voxelotor may potentially modify the course of SCD. In recognition of the critical need for new SCD treatments, the
GBT is currently evaluating voxelotor in the HOPE (Hemoglobin Oxygen Affinity Modulation to Inhibit HbS PolymErization) Study, a Phase 3 clinical study in patients age 12 and older with SCD. Additionally, voxelotor is being studied in the ongoing Phase 2a HOPE-KIDS 1 Study, an open-label, single- and multiple-dose study in pediatric patients (age 6 to 17) with SCD. HOPE-KIDS 1 is assessing the safety, tolerability, pharmacokinetics and exploratory treatment effect of voxelotor.
About GBT
GBT is a clinical-stage biopharmaceutical company determined to discover, develop and deliver innovative treatments that provide hope to underserved patient communities. GBT is developing its lead product candidate, voxelotor, as an oral, once-daily therapy for sickle cell disease. To learn more, please visit www.gbt.com and follow the company on Twitter @GBT_news.
Forward-Looking Statements
Statements we make in this press release may include statements that are not historical facts and are considered forward-looking within the meaning of Section 27A of the Securities Act of 1933, as amended and Section 21E of the Securities Exchange Act of 1934, as amended. We intend these forward-looking statements, including statements regarding the therapeutic potential and safety profile of voxelotor, our ability to implement and complete our clinical development plans for voxelotor, our ability to engage in continued discussions with the
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