Phase II — Sacituzumab govitecan + trastuzumab in HER2+ metastatic breast cancer post-T-DXd. Reported negative primary endpoint at ESMO Breast 2026.
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Trial slides shared by KOLs at ESMO Breast 2026 (#ESMOBreast26). Click any image to expand. OCR text extracted via AWS Textract.
Highest-engagement tweets about this trial, ranked by KOL discussant count (replies + quote-tweets). Replies in green, quote-tweets in blue. Wall Street, stock-promo, and non-substantive replies excluded.
#ESMOBreast26 SATEEN is negative, but highly informative. Mechanistically, SG + trastuzumab was a reasonable idea after T-DXd, especially for tumors with HER2 loss or reduced HER2 dependency. But the efficacy was very limited. ADC resistance is layered: target expression, https
@myESMO #ESMOBC26 @PTarantinoMD SATEEN trial SG +T in 27 TDXd rx’d HER2+ pts w/ MBC. ORR 3.7% in very heavily preRx (5+ lines). Chemo resistant dse w/ topo1 inh ADC post #’s of effective HER2 targeted Rx - nothing works here - impossible task! Nice presentation! @OncoAlert https:
📌 Results from the phase II SATEEN trial Efficacy and safety of sacituzumab govitecan plus trastuzumab in patients with HER2+ metastatic breast cancer after prior trastuzumab deruxtecan (T-DXd) @PTarantinoMD #ESMOBreast26 @OncoAlert #OncoAlertAF https://t.co/cIZv8ZU0t1
SATEEN beautifully presented by @PTarantinoMD SG+ Trastuzumab in pts with HER2+ MBC post TDXd 2-stage single-arm ph 2 trial, didn't get to 2nd stage Median 5 prior lines ORR 3.7% (1 PR in 27 pts) CBR 14.8% #ESMOBreast26 @OncoAlert @DFCI_BreastOnc
SATEEN was a Phase II investigator-initiated trial evaluating sacituzumab govitecan (SG, anti-Trop-2 antibody-drug conjugate) combined with trastuzumab in patients with HER2-positive metastatic breast cancer who had progressed after prior taxane, trastuzumab, and trastuzumab deruxtecan (T-DXd). Presented at ESMO Breast 2026, the trial was designed to test whether re-targeting Trop-2 with SG plus continued HER2 blockade could rescue activity in heavily pretreated patients with limited remaining options. The primary endpoint of objective response rate was not met, with the trial reporting an ORR of 3.7% and short progression-free survival of approximately 2.3 months. Despite the negative result, KOLs noted the trial provides important prospective data on Trop-2 ADCs after T-DXd progression and may inform future biomarker-driven sequencing strategies.
Population: Patients with HER2-positive metastatic breast cancer who had received prior taxane chemotherapy, trastuzumab, and T-DXd, with measurable disease and progression on most recent therapy.
Interventions: Sacituzumab govitecan (SG, anti-Trop-2 ADC with SN-38 payload) administered intravenously in combination with trastuzumab as continued HER2-directed therapy.
Endpoints: Primary endpoint: objective response rate (ORR) by RECIST 1.1. Secondary endpoints included progression-free survival, overall survival, duration of response, and safety/tolerability.
The trial did not meet its primary endpoint. SG plus trastuzumab demonstrated limited efficacy in this heavily pretreated HER2+ population: ORR of 3.7%, median PFS of approximately 2.3 months, and median OS of 9.2 months. KOL commentary highlighted that mechanistic overlap between T-DXd and SG (both targeting topoisomerase I via different antibody-payload combinations) likely contributed to the lack of activity post-T-DXd progression.
The combination demonstrated a manageable safety profile consistent with the known toxicities of each individual agent. No new safety signals emerged with the SG + trastuzumab combination. Adverse events were primarily attributable to SG, with neutropenia and gastrointestinal toxicity being the most common. Discontinuations due to toxicity were limited.
⚠️ SATEEN is an investigational trial that did not meet its primary endpoint and does not support a new clinical indication for SG plus trastuzumab in HER2+ MBC after T-DXd. The negative result highlights the challenge of sequencing topoisomerase-I-targeting ADCs and reinforces the need for biomarker-driven patient selection — particularly Trop-2 expression and tumor heterogeneity assessment — when designing post-T-DXd salvage strategies. KOLs (notably Dr. Yakup Ergün, Dr. Sara Tolaney, Dr. Hope Rugo, Dr. Paolo Tarantino) emphasized this trial's value in providing prospective data that informs the broader question of ADC sequencing in HER2+ disease.
| Handle | Name | Sentiment | Tweet (excerpt) | Imp. |
|---|---|---|---|---|
| @PTarantinoMD | Paolo Tarantino | Positive | It will be the first prospective data of SG after T-DXd and the first data of SG in HER2+ disease. We’re very glad to ha… | 1,405 |
| @dr_yakupergun | Yakup Ergün | Neutral | #ESMOBreast26 SATEEN is negative, but highly informative. Mechanistically, SG + trastuzumab was a reasonable idea after… | 10,528 |
| @DrBarbiOnc | Mali Barbi, MD MSc | Breast & Gyn Oncolo | Neutral | Two prospective phase II trials at #ESMOBC26 just settled something the field has been debating retrospectively. #SATEE… | 3,602 |
| @TejasPatilMD | Tejas Patil | Neutral | ⭐️Everything in this post is directly relevant to #lungcancer as well. #SATEEN answers the value of using sequential ADC… | 1,788 |
| @to_be_elizabeth | Elisabetta Bonzano MD, PhD | Neutral | 📌 Results from the phase II SATEEN trial Efficacy and safety of sacituzumab govitecan plus trastuzumab in patients with … | 1,482 |