Abaloparatide and pelvic fracture healing: a phase 2 randomized placebo-controlled trial

Pelvic fractures result in prolonged pain and immobility. In a randomized controlled trial of patients with pelvic fracture, whether abaloparatide (ABL) vs. placebo (PBO) improves healing at 3 months was evaluated. There was no significant difference in CT radiologic healing, physical performance, or change in pain in ABL vs. placebo. PURPOSE: To determine if abaloparatide (ABL) vs. placebo (PBO) improves radiologic healing, pain, and functional outcome at 3 months in patients with pelvic fracture. METHODS: Postmenopausal women and men ≥ 50 years old, enrolled within 4 weeks of pelvic fracture (n = 48), were randomized to blinded ABL vs. PBO. The primary endpoint, fracture healing at 3 months, was assessed by two radiologists using a 5-point scale for cortical bridging from CT images comparing groups by Jonckheere-Terpstra test. The odds of healing (3 or 4 cortices bridged) were analyzed with Mantel-Haenszel relative risks (RR). Pain was assessed monthly by Numeric Rating Scale (NRS). The Short Physical Performance Battery (SPPB; walk speed, chair stands, and balance) evaluated functional mobility. RESULTS: Groups were balanced with a mean age = 82, 93% were female, 98% had multiple rami fractures, 67% had sacral fracture, and 36% had ≥ 1 displaced fracture. CT images at 3 months showed no significant difference in bridging score distribution (indicator of healing) in patients with ABL vs. PBO (p = 0.15) after adjusting for age, sacral fracture, displacement, or compliance. When evaluating individual fractures (n = 81), similar bridging scores were seen with ABL and PBO (p = 0.13). When patients were stratified as healed or not healed, 39% were healed with ABL and 64% healed with PBO (RR 0.61; 95% CI 0.33, 1.12). When looking at the 81 individual fractures, 47% were healed with ABL and 53% healed with PBO (RR = 0.88; 95% CI 0.55, 1.40). Using least square means controlling for age, sacral, and displaced fracture, NRS pain score was higher in the placebo than the ABL group at baseline (p < 0.05), but there were no further group differences in change in pain score SPPB and TUG scores improved over time in both groups without group differences. CONCLUSION: In this small study, there was no significant difference in CT radiologic healing, physical performance, or change in pain with ABL vs. placebo in patients with acute pelvic fracture. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04249232 registered January 27, 2020.