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BOOST Pharma used its Innovation Spotlight slot at the Cell & Gene Meeting on the Mesa in Phoenix on Tuesday, October 6, 2026 to set out its plan for a pivotal trial of BT-101, its investigational off-the-shelf stem cell therapy for infants with severe osteogenesis imperfecta (OI), with CEO Hans Schambye saying the company expects to be able to start a placebo-controlled trial in up to 80 patients in the middle of next year.
Schambye said BOOST has been in discussions with the FDA and in Europe, and that “there is alignment” on the need for a placebo-controlled trial of that size. Patients would be treated for a year, he said, with the annualized fracture rate as the primary measure. BOOST’s website describes a positive pre-IND interaction with the FDA.
“We are basing the number of patients on an expected reduction of 50 percent, where we saw 70 percent reduction in the previous trials, so we think we are being cautious,” he told the room.
He expects the trial to take about 28 months and put its cost at around €20 million.
The headline data come from an 18-patient clinical trial in OI, in which the company has reported a 70% reduction in fractures. According to Schambye, patients were treated for a year, and the analysis compares fractures before treatment with the first year after treatment stopped. “Every patient had a reduction in the number of fractures,” he said.
Those company-reported figures are a before-and-after comparison in the same children. The trial, understood to be BOOSTB4, is an open-label, non-randomized study registered with safety as its primary outcome. BT-101 is not approved by any regulator.
Natural history data, by his account, show children in this age group averaging two to three fractures a year. That is a comparison with external data, not a concurrent control group.
OI is a genetic disease in which, he said, patients are unable to produce normal collagen. BT-101 is intended to supply cells that reach the bone and, in his words, “start manufacturing the collagen”.
“Think of it like a steel concrete building without the steel,” Schambye said. “You can put in as much concrete as you want, you never get a stable wall. It’s the same for these patients.”
Schambye said the cells are harvested from fetal livers, cryopreserved and transferred to manufacturing partner RoslinCT, then shipped frozen and given as an intravenous infusion. He stressed what is not required, “no preconditioning, no matching is needed, no immune suppression”, attributing this to the cells’ fetal origin.
Schambye said BOOST is in the process of raising a Series A and is “now raising 50 million, which will cover the trial”, along with the manufacturing work needed to support an eventual BLA. He did not specify the currency, having given the trial’s cost in euros.
About BOOST Pharma
BOOST Pharma is a clinical-stage biotechnology company based in Copenhagen, Denmark, founded on research from Karolinska Institutet. Its lead program, BT-101, is an allogeneic mesenchymal stem cell therapy for OI, also known as brittle bone disease, which the company says affects an estimated 1 in 15,000 people and has no FDA- or EMA-approved therapies. BT-101 has Orphan Drug Designation in the US and Europe, and the company also lists an FDA Rare Pediatric Disease Designation.
BOOSTB4 is a Phase 1/2 trial sponsored by Karolinska Institutet, with 18 participants enrolled, in which each patient receives four infusions of first-trimester fetal liver-derived mesenchymal stem cells after birth, or before and after birth. It compares treated children with historical and untreated controls rather than with placebo. In October 2025 BOOST reported two-year follow-up which it said showed an overall fracture reduction of nearly 78% against the pre-treatment period, with more than half of treated patients having no fractures in the second year after the last dose.
BOOST said in January 2026 that it had transferred its manufacturing process to RoslinCT’s facilities in Edinburgh, Scotland. Schambye, previously CEO of Galecto, was appointed CEO in February 2026. The company’s investors include Sound Bioventures, Industrifonden and Karolinska Development (KDventures).
Sources: BOOST Pharma company presentation, Cell & Gene Meeting on the Mesa, October 6, 2026; BOOST Pharma press release; BOOST Pharma company website; ClinicalTrials.gov NCT03706482; BOOST Pharma two-year data release; RoslinCT and BOOST Pharma press release; Sound Bioventures announcement
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