To evaluate the efficacy and safety of the bispecific human epidermal growth factor receptor 2 (HER2)–directed antibody-drug conjugate (ADC) TQB2102 in the neoadjuvant treatment of HER2-positive breast cancer.
This randomized, open-label, multicenter, phase II study (ClinicalTrials.gov identifier: NCT06198751) enrolled HER2-positive patients with stage II and III disease. Patients were stratified by hormone receptor status and randomly assigned (1:1) to receive 6.0 mg/kg once every 3 weeks of TQB2102 for six (cohort 1) or eight cycles (cohort 2) or 7.5 mg/kg once every 3 weeks for six (cohort 3) or eight cycles (cohort 4). The primary end point was total pathologic complete response (tpCR) rate across all four cohorts (n = 26 per cohort). When the lower limit of the 90% CI (Clopper-Pearson exact binomial test) for tpCR rate exceeded 40%, efficacy was considered better than that of the historical control.
Between February 5, 2024, and September 24, 2024, 104 patients were enrolled, with 26 patients in each cohort. The tpCR rates were 57.7% (15 of 26 [90% CI, 43.2 to 71.3]; P = .04) for cohort 1, 76.9% (20 of 26 [90% CI, 62.3 to 87.6]; P < .01) for cohort 2, 61.5% (16 of 26 [90% CI, 46.5 to 74.8]; P = .02) for cohort 3, and 69.2% (18 of 26 [90% CI, 54.6 to 81.3]; P < .01) for cohort 4. The incidence rates of grade ≥3 treatment-related adverse events were 23.1% (6 of 26) for cohort 1, 30.8% (8 of 26) for cohort 2, 30.8% (8 of 26) for cohort 3, and 26.9% (7 of 26) for cohort 4. No treatment-related deaths occurred in any groups.
To our knowledge, this was the first study to report the efficacy and safety of the bispecific HER2-directed ADC TQB2102 in the neoadjuvant setting for HER2-positive breast cancer. TQB2102 showed robust activity and was well-tolerated.
This really feels like a first-line practice changer in PD-L1+ MTNBC—the sacituzumab govitecan/pembrolizumab combination delivering a 3.4-month progression-free survival (PFS) improvement and pushing median PFS past 11 months is quite meaningful. Mature overall survival (OS) data will be interesting to see. Remember to watch closely and consider screening for drug-induced interstitial lung disease(ILD).
ASCENT-03 shows that in first-line, PD-1/PD-L1–ineligible advanced TNBC, sacituzumab improves PFS to 9.7 vs 6.9 months and extends median duration of response (DOR) to 12.2 vs 7.2 months, with similar overall response rate (ORR) (48% vs 46%) and immature overall survival (OS) (21.5 vs 20.2 months) Grade ≥3. Adverse events (AEs) were comparable (66% vs 62%), but sacituzumab had more neutropenia and diarrhea, fewer discontinuations (4% vs 12%), and early-cycle infection-related deaths in patients without primary G-CSF. For PD-1/PD-L1–ineligible mTNBC, SG offers more durable control than chemo with manageable myelosuppression — so consider SG first-line and start G-CSF early in higher-risk patients.
Guidelines for post-mastectomy radiation include patients who received neoadjuvant therapy, with or without residual disease after treatment. A good topic to review.
Our site participated in this study, where patients were tested for ESR1 mutations via circulating tumor DNA (ctDNA). Those who tested positive were switched to camizestrant (Cami), which demonstrated improved progression-free survival.
Vepdegestrant is an oral proteolysis-targeting chimera (PROTAC) estrogen receptor (ER) degrader that directly utilizes the ubiquitin–proteasome system. It was compared to fulvestrant in patients who had received one prior line of hormonal therapy with a CDK4/6 inhibitor. Among patients with ESR1 mutations, Vepdegestrant demonstrated a median progression-free survival (PFS) of 5.0 months versus 2.1 months with fulvestrant. In the overall population, the median PFS was 3.8 months for Vepdegestrant and 3.6 months for fulvestrant, indicating that the drug showed particular efficacy in tumors harboring ESR1 mutations.