Bluebird bio’s Gene Therapy for CALD Gets Accelerated Approval

Shortly after approval of another gene therapy from bluebird bio, the FDA granted accelerated approval for the company’s Skysona (elivaldogene autotemcel), also known as eli-cell, to treat early, active cerebral adrenoleukodystrophy (CALD).

The company also confirmed in a news release that the previous clinical hold on the eli-cel clinical development program has been lifted.

Bluebird has set the wholesale acquisition cost of Skysona at $3 million and expects commercial product to be available by the end of this year through a limited number of qualified treatment centers in the United States.

Last month, FDA also approved Bluebird bio’s Zynteglo (betibeglogene autotemcel), also known as beti-cel, the first cell-based gene therapy to treat adult and pediatric patients with beta-thalassemia who require regular red blood cell transfusions.

The manufacturer set the wholesale acquisition cost of $2.8 million for Zynteglo, and established an outcomes-based contract offering that includes a single upfront payment and up to 80% risk-sharing.

Skysona slows the progression of neurologic dysfunction in boys ages 4-17 with CALD, a rare, progressive, neurodegenerative disease that primarily affects young boys and causes irreversible neurologic decline, bluebird bio said. Nearly half of patients who do not receive treatment die within five years of symptom onset.

Before approval of Skysona, effective treatment options were limited to allogeneic hematopoietic stem cell transplant (allo-HSCT), “which is associated with the risk of serious potential complications including death, that can increase dramatically in patients without a human leukocyte antigen (HLA) matched donor,” bluebird bio said.

Andrew Obenshain

“For the ALD community, this long-awaited approval represents significant hope and offers families a new option where, for many, there had been none,” bluebird bio CEO Andrew Obenshain said in a press release.

“The agony of watching your child slip away is something no parent should have to bear,” said Elisa Seeger, co-founder of ALD Alliance. “We have made significant strides in providing children diagnosed with CALD the best chance at life with early identification of ALD through expanded newborn screening. Yet with limited treatment options, early diagnosis is still cause for despair instead of hope for many families. Today, parents whose boys receive a CALD diagnosis can have renewed hope for the future.”

Skysona’s approval is based on data from bluebird bio’s phase 2/3 study Starbeam with 32 patients and phase 3 ALD-104 with 35 patients. Patients treated with Skysona were assessed using the neurologic function score (NFS) and monitored for the emergence of six major functional disabilities (MFDs) associated with CALD progression including loss of communication, cortical blindness, requirement for tube feeding, total incontinence, wheelchair dependence, or complete loss of voluntary movement. A post-hoc enrichment analysis in symptomatic patients assessed MFD-free survival from onset of symptoms in Skysona treated and untreated patients.

Skysona-treated patients had an estimated 72% likelihood of MFD-free survival at 24 months from time of first NFS ≥ 1, compared with untreated patients who had only an estimated 43% likelihood of MFD-free survival.

As a condition of the Skysona accelerated approval, bluebird has agreed to provide confirmatory long-term clinical data to the FDA. bluebird anticipates that this will include data from the ongoing long-term follow-up study (LTF-304), which follows patients treated in clinical trials for 15 years, and from commercially treated patients.