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.

To determine if abaloparatide (ABL) vs. placebo (PBO) improves radiologic healing, pain, and functional outcome at 3 months in patients with pelvic fracture.

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.

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.

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.

ClinicalTrials.gov identifier: NCT04249232 registered January 27, 2020.