Bone Therapeutics has announced the 12-month efficacy results from the first cohort of seven patients treated with Preob in its phase IIA severe osteoporosis trial. These initial data demonstrate positive effects on pain and osteoporosis blood markers associated with one administration of Preob.
The ongoing trial has been designed to evaluate a single intravenous administration of Preob in patients with severe osteoporosis, defined as those who no longer respond to anti-osteoporotic therapy. In total, 20 patients will be enrolled in the study and followed up over 12 months. The primary endpoints of the study are safety and biodistribution of Preob cells. In addition, effects on clinical symptoms (i.e, pain and general health status) and serum markers of bone turnover are being evaluated.
In this first cohort, patients experienced a pronounced and clinically relevant decrease in pain (of more than 40%), reaching a maximum at six months post-treatment. In a similar patient population, six-month daily subcutaneous administration of the bone anabolic agent teriparatide only achieved a 30% decrease in pain. A same positive trend was also observed on the general health status of Preob-treated patients.
Moreover, analysis of the profile of bone markers in the blood has shown a dual trend: (i) in an early phase of the 12-month follow-up, a decrease (of more than 25%) of bone resorption (bone breakdown) markers was observed, while bone formation markers were either unaffected or even slightly increased and (ii) in a later phase of the 12-month follow-up, a continuous increase in bone formation markers was observed with a moderate increase in bone resorption markers. According to a press release from Bone Therapeutics, he unexpected early decrease in bone resorption markers is remarkable, as studies have shown that in a comparable population of severe osteoporosis patients, where bone turnover is totally suppressed, antiresorptive drugs have no additional effect on bone resorption.
According to the release, these preliminary results seem to indicate that one administration of Preob could progressively stimulate bone remodelling, with a bone formation-to-resorption ratio more favourable than that generally reported with other anti-osteoporotic agents in the same patient population. By comparison, while bone anabolic treatments in general show stronger effects on bone formation markers, their bone formation-to-resorption ratio is less favourable, with bone resorption twice as highly increased as bone formation. Therefore, this surprising effect of Preob on bone turnover suggests a different—potentially more favourable—mechanism-of-action compared to existing therapies.