FDA Postpones Decision on Luspatercept-aamt for Anemia in Adults With NTD Beta Thalassemia

The Prescription Drug User Fee Act action date for luspatercept-aamt as a potential treatment for adult patients with non-transfusion-dependent (NTD) beta thalassemia has been extended to June 27, 2022, according to an announcement by Bristol Myer Squibb.¹

The extension was made based on a written response to an information request which the FDA determined to be a major amendment to the supplemental biologics license application (sBLA), requiring an additional 3 months for the FDA’s full review after the application was previously granted priority review. The sBLA was supported by data from the phase 2 BEYOND clinical trial of luspatercept in combination with best supportive care in patients with NTD beta thalassemia.

In the phase 2, double-blind, randomized, placebo-controlled, multicenter BEYOND study (NCT03342404), luspatercept 1 mg/kg administered every 3 weeks was combined with best supportive care (BSC) and compared with an arm of subcutaneous placebo administered every 21 days plus BSC.²

The key study goal was to determine the efficacy and safety of luspatercept. The primary end point of the study is the percentage of patients achieving erythroid response. The key secondary end points included various patient-reported outcomes, mean change from baseline in hemoglobin values in absence of transfusion and percentage of patients with an erythroid response.

According to the initial results from 145 patients with NTD beta thalassemia, 77.7% of patients who received luspatercept achieved a hemoglobin increase compared with none of the patients in the placebo arm (P < .0001). The primary end point of ≥ 1.0 g/dL mean increase in hemoglobin was met. The key secondary end point also had a positive result with 52.1% of patients in the luspatercept/BSC arm achieving a mean hemoglobin increase of ≥ 1.5 g/dL compared to baseline. In the placebo/BSC arm, no patients achieved an increase in hemoglobin from baseline (P < .0001). Further, changes from baseline in patient-reported outcomes were associated with increases in hemoglobin.³

The percentage of patients in the luspatercept arm who remained transfusion-free at weeks 1 through 24 was 89.6% of compared with only 67.3% of the placebo group (P = .0013).

Cases of bone pain, headache, and arthralgia were treatment-emergent adverse events that occurred in at least 5% of patients in the BEYOND study. In the luspatercept arm, bone pain was observed in 6.1% of patients in each respective arm. Headache occurred in 30.2% of the luspatercept arm versus 20.4% of the placebo arm, and arthralgia occurred in 29.2% versus 14.3%, respectively.

Luspatercept, a first-in-class therapeutic drug that is indicated in the United States for the treatment of anemia in adult patients with beta-thalassemia who require regular red blood cell transfusions, and for anemia failing an erythropoiesis-stimulating agent and requiring 2 or more red blood cell units over 8 weeks in adult patients with very low- to intermediate-risk myelodysplastic syndrome with ring sideroblasts with myelodysplastic/myeloproliferative neoplasm with ring sideroblasts and thrombocytosis.¹

_REFERENCES:

_{1. Bristol Myers Squibb announces new prescription drug user fee act goal date for Reblozyl® (luspatercept-aamt) supplemental biologics license application. News release. March 25, 2022. Accessed March 25, 2022. https://bit.ly/3Da8MUe}

_{2. A study to determine the efficacy and safety of luspatercept in adults with non transfusion dependent beta (β)-thalassemia (BEYOND). Clinicaltrials.gov. Accessed December 3, 2021. https://bit.ly/2ZRBJ8h}

_{3. Bristol Myers Squibb and Acceleron present first results from phase 2 BEYOND Study of Reblozyl® (luspatercept-aamt) in adults with non-transfusion Dependent (NTD) beta thalassemia. June 11, 2021. Accessed December 3, 2021. https://bit.ly/3xQAWkt}