How do you treat a patient with TNBC, BRCA WT, who received KEYNOTE-522 with residual disease post neoadjuvant therapy?

Yes, in this (unfortunately high-high-risk) situation, I would continue adjuvant pembrolizumab as per the KEYNOTE-522 trial, and add adjuvant capecitabine per the CREATE-X trial. Though these two agents were not specifically studied together in this exact setting, there is other safety data to reassure us that they can be combined safely. I would also make sure that the patient had germline genetic testing and does not have a BRCA1, BRCA2, or PALB2 germline mutation. If she had one of those mutations, I would use adjuvant olaparib in place of adjuvant capecitabine.

Yes, in this situation, these are patients at higher risk of recurrent disease. Would continue pembrolizumab and offer capecitabine adjuvant therapy. There is safety data for this combination (Page et al., Journal of Clinical Oncology 2018) published in metastatic breast cancer, with no alarm symptoms noted.

Agree with Dr. @Dr. First Last to ensure germline testing has been completed to ensure the patient is not a candidate for adjuvant olaparib.

Given that KEYNOTE-522 did not allow adjuvant capecitabine in patients who had residual disease following neo-adjuvant chemotherapy, we do not have data about the safety and efficacy of capecitabine together with pembrolizumab in this clinical setting. One could certainly make a case for changing pembrolizumab to adjuvant capecitabine, but my inclination would be to continue pembrolizumab for 9 additional cycles. The reason I am leaning towards this approach is because on early event free survival read out of the KEYNOTE-522 trial, EFS is trending towards higher benefit in the patients who received adjuvant pembrolizumab compared to placebo. If adjuvant radiation is required, it can be given concurrently with pembrolizumab since the KEYNOTE...