There are few effective options for salvage therapy in elderly patients with relapsed or refractory angioimmunoblastic T-cell lymphoma (AITL). The anti-CCR4 antibody mogamulizumab works via antibody-dependent cytotoxic activity, reduces regulatory T cells, and evokes antitumor immunity in cancer patients. We report a 78-year-old patient with refractory AITL receiving a new immunochemotherapy consisting of sequential mogamulizumab administration followed by the GDP (gemcitabine, dexamethasone and cisplatin) regimen. A favorable consolidative effect of the GDP regimen could be observed in the patient who had partial remission after administration of mogamulizumab monotherapy. The regimen showed an acceptable toxicity profile without serious autoimmunity and an expected treatment response for the elderly patient with primary refractory AITL. This clinical case is the first report of salvage chemotherapy including mogamulizumab for primary refractory AITL described in the literature.