Lenvatinib and Pembrolizumab to Treat Patients With Anal or Rectum Cancer That Has Gotten Worse After Initial Treatment

Must have received: chemotherapy — first line

following progression on first line chemotherapy or chemoradiation therapy

Must have received: chemoradiation therapy — first line

following progression on first line chemotherapy or chemoradiation therapy

Cannot have received: anti-PD-1 therapy

Has received prior therapy with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or with an agent directed to another stimulatory or co-inhibitory T-cell receptor (eg, CTLA-4, OX-40, CD137)

Cannot have received: systemic anti-cancer therapy

Exception: within 4 weeks prior to study registration

Has received prior systemic anti-cancer therapy, including an investigational agent(s) or investigational device, within 4 weeks prior to study registration

Cannot have received: radiation therapy

Exception: within 2 weeks of study registration; 1-week washout permitted for palliative radiation (≤2 weeks of radiotherapy) to non-CNS disease

Has received prior radiotherapy within 2 weeks of study registration. Participants must have recovered from all radiation-related toxicities, not require corticosteroids, and not have had radiation pneumonitis. A 1-week washout is permitted for palliative radiation (defined as ≤2 weeks of radiotherapy) to non-CNS disease.