Bone up on first osteoporosis data

The first data on Bone Therapeutics’ cell therapy Preob in severe osteoporosis, showing that the cells accumulate in the bone as hoped, is the initial step towards showing that it can actually spur bone growth.

Preob is the Brussels group’s lead project and is in phase III trials for osteonecrosis and non-union fractures, but osteoporosis is a vastly larger market and represents the real opportunity. Bone Therapeutics’ share price was up 6% to €21.87 in afternoon trading today, and if the full data from the phase IIa osteoporosis trial, expected in autumn, do show efficacy the readout could be more meaningful for the company's shares than anything the phase III studies could report.

Once a year

However, it should be remembered that the trial is small – the data are from just seven of the eight patients it enrolled, as one patient was signed up but did not meet the inclusion criteria and was not treated – and as such the results are far from conclusive.

But it is probably the most promising showing that could be made at this stage. Following a single intravenous infusion of Preob, Bone Therapeutics said osteoblastic cells had migrated to the vertebrae and pelvis within 72 hours. There were no treatment-related serious adverse events.

Bone Therapeutics is studying the therapy in the population that will allow it the easiest path through the regulatory system: those with severe disease who do not respond to existing anti-osteoporotic therapy.

It is possible that the company has a plan for moving up the treatment cascade, however. According to analysts from Bryan, Garnier & Co, the cells are designed to be administered as a single infusion just once a year; current options must be administrated subcutaneously up to twice a month.

That said, the drug forecast to be the bestseller in 2020 according to EvaluatePharma, Amgen’s Prolia, is a subcutaneous injection given every six months.

Bone Therapeutics is around a year away from opening manufacturing facilities near Brussels that will allow it to produce Preob and its other therapy, Allob, in commercial quantities (Interview – Bone Therapeutics to list in Europe and partner in the US, February 2, 2015).

€1bn?

But before any discussion about commercialisation can really begin the positive clinical data must continue to flow. Bryan, Garnier & Co analysts write that a positive efficacy readout from the phase IIa osteoporosis would prompt them to raise their expectation of success for the project from 10% to 20%. They suggest that Preob has the potential for peak sales, in 2028, of nearly €1bn across all its indications in Europe alone.

Well, maybe. It is perhaps more foreseeable that a win on efficacy might allow Bone Therapeutics to snag a partner for Preob – always its plan for this asset, at least in the US.

To contact the writer of this story email Elizabeth Cairns in London at elizabethc@epvantage.com or follow @LizEPVantage on Twitter

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