ECTS2014 Hot Topic Oral Communications (1) (5 abstracts)
1Radius Health Inc., Cambridge, Massachusetts, USA; 2CCBR, Clinical Research, Ballerup, Denmark.
Background: Treatments that result in greater increases in bone mass of normal quality by increasing bone formation rather than decreasing resorption are needed. Abaloparatide is a synthetic analog of PTHrP1-34 that has shown strong efficacy to increase bone mass and bone strength in animals. We conducted two phase 2 placebo-controlled studies both of which included abaloparatide 80 μg sc daily (ABL) in postmenopausal women with osteoporosis. Study 1 also included teriparatide (Forteo) 20 μg sc daily (TER). Together, these studies included 95, 94 and 45 women treated with placebo, ABL and TER respectively.
Results: Relative to placebo, ABL increased spine BMD at 24 weeks by 5.1 and 5.8% and increased total hip BMD by 2.2 and 2.7% in Studies 1 and 2 respectively (all P<0.005). TER increased spine BMD by 3.9% (P<0.001), but had no significant effect on total hip BMD relative to placebo (0.1%). The increase in CTX was substantially higher with TER, reflecting a greater increase in bone resorption. In a subset extension of Study 1, mean increases in BMD at 48 weeks relative to placebo were 12.2 and 7.9% for ABL and TER at the spine and 2.7, and 1.3 at the total hip respectively. Both ABL and TER were generally well tolerated.
Comments: ABL induces consistent, rapid, substantial increases in BMD over up to 48 weeks, which are greater than those seen with either TER or, historically, with any other currently-approved treatment for osteoporosis. The greater BMD efficacy is most likely due to greater selectivity of ABL to increase bone formation with a less marked increase in bone resorption relative to TER. ABL is currently in a >2400-patient, phase 3, 18-month, placebo- and TER-controlled, fracture study which will complete this year. ABL is a promising new therapy for treatment of osteoporosis.