Romosuzumab Outperforms Teriparatide in Post-Bisphosphonate Osteoporosis Save

The STRUCTURE trial results have been reported in Lancet and have shown that after 12 months of therapy, romosozumab (ROMO) had superior gains in bone mineral density (BMD) compared to teriparatide (TER) in women with postmenopausal osteoporosis who have previously taken bisphosphonate therapy.

This phase 3 trial enrolled women (aged ≥55 to ≤90 years) with postmenopausal osteoporosis who had previously received oral bisphosphonate therapy for > 3 years and had a BMD T score of −2·5 or lower at the total hip, femoral neck, or lumbar spine; and a history of fracture. Patients were treated withe either ROMO (210 mg once monthly) or subcutaneous TER (20 μg once daily) and the primary endpoint was the percentage change in BMD at 12 months.

A total of 436 patients were randomized. At 12 months, the mean change in hip BMD was 2·6% (95% CI 2·2 to 3·0) for ROMO and −0·6% (−1·0 to −0·2) for TER treated patients (p<0·0001).

The frequency of adverse events and serious AEs were balanced between treatment groups. The most frequently reported adverse events were nasopharyngitis, hypercalcaemia and arthralgia. There were six (3%) patients in the romosozumab group compared with 12 (6%) in the teriparatide group with adverse events leading to drug withdrawal.

Thus for those requiring a bone-forming agent after bisphosphonates, it appears that the use of the anti-sclerostin drug, romosozumabm, may lead to better gains in hip BMD compared to teriparatide.

To date, more than 11,000 patients have received ROMO in clinical trials. Yet last month the FDA issued a complete response letter to the  manufacturers over concerns about cardiovascular events in subsequent trials. FDA has asked UCB and Amgen to provide additional data on the safety and efficacy of ROMO in their phase 3 active-comparator ARCH study and BRIDGE study.