Importance of prompt antiresorptive therapy in postmenopausal women discontinuing teriparatide or denosumab: The Denosumab and Teriparatide Follow-up study (DATA-Follow-up).

When teriparatide and denosumab are discontinued, bone mineral density (BMD) abruptly decreases. To compare rates of bone loss in postmenopausal women who discontinue denosumab or teriparatide and receive no additional prescription osteoporosis medications to women who discontinue these drugs followed by prompt antiresorptive therapy, we asked women concluding the Denosumab and Teriparatide Administration (DATA) study and its extension, DATA-Switch, to return for BMD measurements 1-2years after study completion. In these studies, women received 2-years of either teriparatide, denosumab or both medications followed by 2-years of the alternate therapy (women who received combination therapy initially received an additional 2-years of denosumab alone). Fifty of 69 women who completed DATA-Switch returned after a mean of 15.4±3.5months. Of the 28 women who received antiresorptive therapy (10 denosumab, 10 oral bisphosphonates, 8 intravenous zoledronic acid), the mean interval between ending DATA-Switch and beginning antiresorptive therapy was 3.8±3.1months. In the 22 women not receiving follow-up therapy, femoral neck, total hip, and spine BMD decreased by -4.2±4.3%, -4.5±3.6%, and -10.0±5.4%, respectively, while BMD was maintained in those who did receive follow-up antiresorptive drugs (femoral neck, total hip, and spine BMD changes of -0.6±2.7%, -0.8±3.1%, and -1.2±4.7%, respectively, P<0.001 for all between-group comparisons). Among untreated women, femoral neck BMD decreased more in those discontinuing denosumab (-5.8±4.0%) than in those discontinuing teriparatide (-0.8±2.6%, P=0.008). Total hip BMD, but not spine BMD, showed a similar pattern. Among treated women, denosumab increased femoral neck and total hip BMD more than bisphosphonates while BMD changes at the spine did not differ significantly. In summary, the large teriparatide and denosumab-induced gains in BMD achieved with 4years of intensive therapy in the DATA and DATA-Switch studies were maintained in patients who received prompt antiresorptive therapy but not in those left untreated. These results demonstrate the negative consequences of delaying consolidation therapy in women treated with these drugs and underscore the importance of timely medication transitions in such patients.