PURPOSE The US Food and Drug Administration approved fam-trastuzumab deruxtecan-nxki (DS-8201a, T-DXd) for the treatment of adult patients with unresectable or metastatic human epidermal growth factor receptor 2 (HER2)-low (immunohistochemistry 1 + or immunohistochemistry 2+/in situ hybridization–) breast cancer who have received a prior chemotherapy in the metastatic setting or developed disease recurrence during or within 6 months of completing adjuvant chemotherapy. PATIENTS AND METHODS Approval was based on DESTINY-Breast04, a phase III, randomized, open-label, multicenter trial in patients with unresectable or metastatic HER2-low breast cancer, determined at a central laboratory. A total of 557 patients were randomly assigned (2:1) to receive either T-DXd 5.4 mg/kg intravenously once every 3 weeks (n = 373) or physicians' choice of chemotherapy (n = 184). RESULTS The study met its primary efficacy end point of progression-free survival (PFS) by blinded independent central review assessment in the hormone receptor–positive (HR+) cohort (N = 494) with an estimated hazard ratio (HR) of 0.51(95% CI, 0.40 to 0.64; P < .0001). Key secondary end points were also met, including PFS in the intent-to-treat population with an HR of 0.50 (95% CI, 0.40 to 0.63; P < .0001), overall survival (OS) in the HR+ cohort with an HR of 0.64 (95% CI, 0.48 to 0.86; P = .0028) and OS in the intent-to-treat with an HR of 0.64 (95% CI, 0.49 to 0.84; P = .0010). The safety profile of T-DXd was consistent with previously approved indications, and no new safety signals were observed in this study population. CONCLUSION The approval of T-DXd in HER2-low metastatic breast cancer was based on statistically significant and clinically meaningful PFS and OS improvements observed in the DESTINY-Breast04 trial and represents the first approved therapy specifically for the treatment of HER2-low metastatic breast cancer.

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Purpose: To evaluate the impact of FDA's 2013 zolpidem Drug Safety Communications (DSCs), which recommended lowering the initial dose to mitigate drowsiness, on national estimates of zolpidem users and zolpidem exposure cases. Methods:We analyzed trend changes of national zolpidem users from the IQVIA Total Patient Tracker (TPT) and zolpidem exposure cases reported to the National Poison Data System (NPDS), 2009-2018. To control for time varying confounding, the adjusted trends were analyzed using simple and controlled interrupted time series (ITS). We also adjusted for seasonal changes. Three sedating antidepressants were used together as a control. Results:The national estimates of high-dose zolpidem users in TPT decreased significantly in the month immediately post-DSC; the absolute level decrease was À12.51 (95% CI: À14.12, À10.89) per 10 000 U.S. population relative to sedating antidepressants. The trend continuously decreased post-DSC, resulting in a 59% overall decrease by the end of the study period. There was a larger decrease in high-dose zolpidem use in females than in males. There was a level decrease of zolpidem exposure cases in the NPDS immediately post-DSC, À0.37 absolute decline (95% CI, À0.53, À0.20) per 10 000 national zolpidem users; or À1.33 absolute decline (95% CI, À1.54, À1.13) per 1000 total NPDS exposure cases relative to sedating antidepressants. Similar patterns were observed for cases reporting drowsiness. The results from the single ITS and controlled ITS were similar.Conclusions: Zolpidem users and exposure cases decreased significantly post-DSC, suggesting practitioners and patients became aware of and responded to the zolpidem DSCs. K E Y W O R D S controlled interrupted time series, drug safety communication, regulatory impact Key Points• A controlled interrupted time series analysis was performed to evaluate the impact of the FDA's zolpidem DSCs in 2013, which recommended lowering the initial dose to mitigate drowsiness.