ASCO 2024 preview – first look at Kelun’s registrational TROP2 dataset
The anti-TROP2 ADC sacituzumab tirumotecan has been in the spotlight, having been licensed by Kelun to Merck & Co in 2022, and subsequently put into a pivotal programme comprising nearly 10,000 patients. Last December Kelun’s first filing, for third-line triple-negative breast cancer, was accepted by China’s regulator, and an ASCO abstract has just revealed the impressive-looking data on which this is based. The phase 3 study in question, OptiTROP-Breast01, was toplined positive back in August, and the abstract shows a 69% reduction in risk of progression or death at a June 2023 cutoff. Even more dramatic is that an OS benefit was already seen at first interim analysis (November cutoff), amounting to a 47% reduction in risk of death. Also of interest will be the fact that PFS data are split by biomarker, and show a more pronounced effect in TROP2-expressing patients. Lack of information on patients’ baseline characteristics makes it impossible to relate these Chinese results to a realistic western population, but in any case Merck isn’t studying saci-T in this setting. Rather, its phase 3 TNBC trial is in the adjuvant setting, while Kelun is additionally running a Chinese pivotal front-line study.
Summary of OptiTROP-Breast01 trial in third-line* triple-negative breast cancer
Sacituzumab tirumotecan | Physician’s choice** | |
|---|---|---|
| mPFS (all-comers) primary endpoint | 5.7mth | 2.3mth |
| HR=0.31, p<0.00001 | ||
| mPFS (TROP2-expressing)^ secondary endpoint | 5.8mth | 1.9mth |
| HR=0.28 | ||
| mOS (all-comers) secondary endpoint | NE | 9.4mth |
| HR=0.53, p=0.0005 | ||
| Gr ≥3 neutrophil count decrease | 32.3% | 47.0% |
| Gr ≥3 anaemia | 27.7% | 6.1% |
| Gr ≥3 white blood cell count decrease | 25.4% | 36.4% |
Notes: 21 Jun 2023 data cutoff for PFS, and 30 Nov 2023 for OS (first interim analysis); *patients had received two or more therapies, including at least one in the metastatic setting; **eribulin, vinorelbine, capecitabine or gemcitabine; ^IHC semi-quantitative H-score >200. Source: ASCO.
The ASCO annual meeting takes place in Chicago on 31 May to 4 June.
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