Roughly 80 percent of postmenopausal women with severe osteoporosis who qualify for anabolic therapy never receive it, not because the drugs fail, but because every approved anabolic requires a subcutaneous injection. That administration gap is the entire commercial and clinical rationale behind Entera Bio‘s EB613, and the company now has FDA alignment on a registrational path that could actually close it.
The FDA accepted Entera’s plan for a single, randomized, double-blind, placebo-controlled Phase 3 trial in approximately 750 postmenopausal women, with a primary endpoint of percent change from baseline in total hip bone mineral density at Month 12. That 12-month data window, rather than a longer fracture-incidence study, will anchor the NDA submission. The agency also agreed to an open-label extension following patients through 24 months, with up to 18 months of data folded into the NDA’s 120-day safety update. Phase 3 initiation is planned for late 2026 and topline results are expected in the second half of 2028. Crucially, the NDA package will use the 505(b)(2) pathway, leaning on a scientific bridge to Forteo (teriparatide SC injection), which means Entera does not have to independently establish the fracture-reduction mechanism from scratch.
The Phase 2 foundation is credible. A 161-patient, six-month, placebo-controlled study met both primary pharmacodynamic endpoints and secondary BMD endpoints, with statistically significant gains at the lumbar spine, total hip, and femoral neck. The total hip BMD increase matched what Forteo has reported at six months. Phase 3 is powered to demonstrate BMD improvements comparable to Forteo at 12 months, changes the company associates with a 60 to 80 percent relative reduction in vertebral fracture risk. A Phase 1 presentation at ENDO 2026 added further support, showing that a single EB613 tablet produces pharmacokinetic and pharmacodynamic profiles comparable to both the multi-tablet formulation used in Phase 2 and to Forteo itself. That simplification from multiple tablets to one matters operationally for both patients and trial logistics.
The one number to track as enrollment opens in late 2026 is the trial’s total hip BMD change at Month 12 relative to Forteo’s historical benchmark. If EB613 hits or exceeds that comparator threshold, the 505(b)(2) bridge holds and the NDA submission timeline firms. If it falls short, the entire regulatory architecture requires renegotiation.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
