Beam Therapeutics gave an initial look at the first handful of patients who received its experimental gene-edited treatment for sickle cell disease.
As of July 2, six people with severe sickle cell disease have been dosed with its therapy, which uses base editing to turn on a functioning fetal form of the blood protein hemoglobin, the biotech said Tuesday.
One patient in the Phase 1/2 trial died from respiratory failure four months after getting BEAM-101, which was deemed likely related to the busulfan conditioning required to receive the gene-edited therapy.
“It was a very sad outcome,” Beam CEO John Evans said in an interview before the data came out. “That reminds us, frankly, of how severely sick these patients are where they’re making the decision to try these curative therapies but that have real risks.”
Beam’s shares
$BEAM
fell 10% Tuesday morning.
In the four patients with at least one month of follow-up, Beam reported its therapy induced fetal hemoglobin by greater than 60% and reduced sickle cell hemoglobin by 36% or less, an effect that the company said “was sustained over time.” Evans said the numbers were similar to what was seen in largely asymptomatic sickle trait carriers and higher than what’s been reported for Vertex’s sickle cell therapy Casgevy, which is one of two approved gene therapies for the disease.
Beam also reported a median of 17 and 20 days for neutrophil and platelet engraftment, respectively. Evans noted that timeline was shorter than Casgevy’s. “That’s frankly less time in the hospital, less risk of infection,” he said.
In Casgevy’s pivotal
clinical trial
for sickle cell disease, median neutrophil and platelet engraftment time was 27 and 32 days, respectively.
By using base editing, Beam believes it is not only able to make a precise single-letter change to the DNA, it is also able to do so in a way that doesn’t require double-stranded breaks, which Evans described as “gentler on the cell.” The data are still too early to determine whether outcomes on Beam’s therapy are meaningfully different than Casgevy and bluebird bio’s Lyfgenia, but Evans pointed to initial signs that he said show “the advantages of that coming out.”
Behind Evans’ pitch that Beam’s experimental sickle cell therapy can do better than the approved ones are questions about the commercial appetite for a third gene therapy for sickle cell. Editas Medicine, another player trying to break into the sickle cell therapy market,
announced
last month that it is pivoting away from its clinical sickle cell therapy and focusing on an
in vivo
approach.
The launches of the first two sickle cell gene therapies — which were approved the same day last year — have taken time. Vertex
reported
Monday that 40 patients have started the process to receive its therapy, and it made $2 million in revenue from the first patient dosed in the third quarter. Bluebird bio
said
in late September that it had 41 patient starts across its three gene therapies, though it also announced it was cutting costs and laying off staff at that time.
Beam’s data are still very early, but the company said so far no patients experienced extreme bouts of pain called VOCs that are related to sickle cell disease. The biotech also reported that markers of hemolysis — the process by which blood cells break down — either normalized or improved for all patients.
Treatment with BEAM-101 is a long process that involves extracting a patients’ blood stem cells and editing them to turn on fetal hemoglobin. Patients receive intense chemotherapy conditioning to clear space in their bone marrow for the new cells, which are then reinfused. The conditioning also comes with a high risk of infertility.
Beam’s data were shared in an abstract released as part of the annual ASH meeting, which will take place in December. Beam expects to present data with longer follow-up and from seven patients, and it will also detail additional preclinical results from two monkeys that received an experimental regimen it is developing that aims to do away with the intense conditioning.
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