With positive data in hand from its phase IIb trial testing immunotherapy candidate OST-HER2 in osteosarcoma, OS Therapies Inc. anticipates a regulatory filing this year seeking accelerated approval from the U.S. FDA, putting the firm on track to receive a potentially profitable rare pediatric disease priority review voucher that could help fund further R&D work. Should OST-HER2 go on to win approval, it would mark the first new therapy in more than 40 years for osteosarcoma, an aggressive bone cancer characterized by high rates of metastases, often to the lungs, and disease recurrence.