KEY TAKEAWAYS
- The phase 3 KEYNOTE-355 study reported the efficacy of pembro + chemo for pts who had disease control and discontinued chemo before pembro and for pts who experienced immune-mediated AEs.
- Patients were randomized 2:1 to receive either pembro or placebo for 35 cycles combined with chemo.
- The trial confirmed that pembro + chemo is effective irrespective of discontinued chemo or immune-mediated AEs.
The KEYNOTE-355 study demonstrated that patients (pts) diagnosed with advanced triple-negative breast cancer (TNBC) and a PD-L1 CPS ≥ 10 who received primary treatment with a combination of pembrolizumab (pembro) and chemotherapy (chemo) showed improved progression-free survival (PFS) and overall survival (OS) outcomes compared to those who only receive chemo with a placebo. The study reported efficacy results for pts who had disease control and stopped chemo before starting pembro and those who experienced immune-mediated adverse events (AEs).
In the phase 3 trial, pts with untreated locally recurrent inoperable or metastatic TNBC were randomized 2:1 to receive either pembro (200 mg Q3W) or placebo for 35 cycles in combination with chemo (nab-paclitaxel, paclitaxel, or gemcitabine/carboplatin). The treatment continued until progression, intolerable toxicity, or completion of 35 cycles (for pembro/placebo). Patients could discontinue chemo independently of pembro/placebo and vice versa. The study results demonstrated that combining pembro and chemo improved PFS and OS. Furthermore, pts who achieved a best objective response of complete response (CR), partial response (PR), or stable disease (SD) lasting ≥24 wk and received their last dose of chemo >21 days before their last dose of pembro were evaluated in addition to those who experienced immune-mediated AEs while receiving pembro and chemo.
The study randomized pts to receive either pembro and chemo (n=566) or placebo and chemo (n=281). At the data cutoff, 317 pts in the pembro and chemo group demonstrated CR, PR, or SD for at least 24 weeks. Furthermore, discontinuing chemo before pembro was linked with comparable efficacy to that observed in the general population, regardless of tumor PD-L1 CPS. Also, pts who experienced immune-mediated AEs displayed antitumor activity, irrespective of tumor PD-L1 CPS.
The KEYNOTE-355 study showed that pembro + chemo is effective regardless of discontinued chemo or immune-mediated AEs.
Clinical Trial: https://classic.clinicaltrials.gov/ct2/show/NCT02819518
Rugo, H.S., Cescon, D.W., Im, S., Yusof, M.M., Gallardo Araneda, C.E., Lipatov, O., Cruz, F., Barrios, C.H., Hegg, R., Martín, E. H., Torregroza Otero, M.A., Turner, N., Árkosy, P.F., Tarnawski, R., Karantza, V., Pan, W., Guo, Z., Cortes, J. Annals of Oncology (2023) 8 (1suppl_4): 101223-101223. 10.1016/esmoop/esmoop101223.
