KEY TAKEAWAYS
- The phase III DESTINY-Breast04 study analyzes T-DXd’s efficacy over TPC in pts with HER2-low, ER expression IHC 0-10% mBC.
- HER2-low mBC patients previously treated with 1 or 2 lines of chemotherapy were randomized (2:1) to T-DXd or TPC.
- T-DXd showed improved PFS and OS vs TPC in the participants.
In the phase III DESTINY-Breast04 trial, patients (pts) with HER2-low (HER2 IHC 1+ or IHC 2+/ISH−) mBC who had previously received 1 or 2 lines of chemotherapy were randomized (2:1) to T-DXd or TPC (physician’s choice of chemotherapy). The primary data cutoff (Jan 11, 2022) was utilized for exploratory analyses of efficacy and safety for pts with ER IHC 0-10%.
The study included 110 pts (ER IHC 0% n = 58; ER IHC 1-10% n = 52). Based on the results, pts with ER IHC 1-10% treated with T-DXd showed longer PFS (median PFS, 8.4 months with T-DXd vs 2.6 months with TPC; hazard ratio, 0.24 [95% CI, 0.12-0.48]) and OS (hazard ratio, 0.35 [95% CI, 0.16-0.75]) vs TPC.Among ER IHC 0-10% pts, the most common any-grade treatment-emergent adverse events (TEAEs; ≥20% of pts in either arm) comprised of nausea, vomiting, fatigue, decreased appetite, alopecia, constipation, anemia, diarrhea, increased transaminases, decreased white blood cell count, and decreased neutrophil count. Grade ≥3 TEAEs occurred in 40 (53.3%) and 24 (75.0%) pts in the T-DXd and TPC groups, respectively.
T-DXd demonstrated consistent efficacy in pts with HER2-low ER 1-10% mBC, similar to outcomes observed in HER2-low ER 0% mBC patients. Survival rates were also comparable. The safety of T-DXd in the ER IHC 0-10% subgroup was found to be manageable and in line with the primary analysis.
Source: https://oncologypro.esmo.org/meeting-resources/esmo-breast-cancer-congress/destiny-breast04-subgroup-analyses-of-trastuzumab-deruxtecan-t-dxd-vs-treatment-of-physician-s-choice-tpc-in-patients-pts-with-human-epiderma
Clinical Trial: https://classic.clinicaltrials.gov/ct2/show/NCT03734029
Cameron, D.A., Jacot, W., Yamashita, T., Vidal Losada, M.J., Schmid, P., Lee, K.S., De Laurentiis, M., Zagouri, F., Ueno, N.T., Prat, A., Harbeck, N., Yerushalmi, R., Lu, Y., Gombos, A., Orbegoso, C.M.A., Cheng, F., Yung, L., Rajagopalan, R., Tsurutani, J., Modi, S. Annals of Oncology (2023) 8 (1suppl_4): 101223-101223. 10.1016/esmoop/esmoop101223
