Decrease in CA19-9 at week 8 identified more patients with survival benefit than radiologic response in patients with metastatic pancreatic cancer, according to a study published in the Annals of Oncology.1
The link between CA19-9 decreases and prolonged overall survival were investigated in an exploratory analysis of the phase 3 MPACT study, where patients were randomly assigned to receive nab-paclitaxel plus gemcitabine vs gemcitabine alone.
A total of 252 patients who received nab-paclitaxel and gemcitabine and 202 patients who received gemcitabine and had baseline and week 8 CA19-9 measurements were included in the study.
Results showed that patients with any CA19-9 decline (80%) vs those without (20%) demonstrated improved overall survival (median 11.1 months vs 8.0, respectively).
Patients in the combination arm with any decrease in CA19-9 (n = 206) at week 8 had a confirmed overall response rate of 40% vs 13% in those without a decrease and a median overall survival of 13.2 vs 8.3 months, respectively (P = .001). Patients in the gemcitabine alone arm with a decrease (n = 159) had a confirmed overall response rate of 15% vs 5% in those without a decrease at week 8.
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Patients in the combination arm had an unconfirmed radiologic response of 16% vs 6% in the monotherapy arm at week 8 (median overall survival 13.7 months vs 14.7 months, respectively). Those with stable disease and any decrease in CA19-9 had a median overall survival of 13.2 months vs 9.4 months, respectively.
- Chiorean EG, Von Hoff DD, Reni M, et al. CA19-9 decrease at 8 weeks as a predictor of overall survival in a randomized phase III trial (MPACT) of weekly nab-paclitaxel plus gemcitabine vs gemcitabine alone in patients with metastatic pancreatic cancer [published online ahead of print January 22, 2016]. Ann Oncol. doi: 10.1093/annonc/mdw006.