RecruitingPhase 2Drug trialPulsed Dose Chemotherapy Plus Pembrolizumab in Recurrent/Metastatic HNSCCThe rationale for the new sequence of pulsed dose chemotherapy proposed in this trial is based on the hypotheses that current standard dosing of chemotherapy plus pembrolizumab ultimately suppresses the immune system and has a negative effect on the efficacy of the anti-PD-1 monoclonal antibody (mAb) therapy and that chemotherapy given after anti-PD-1 mAb therapy is associated with higher efficacy.