ORIENT-4

NK/T-cell lymphoma that relapses after an asparaginase-based regimen had no standard. Its tumour cells commonly express PD-L1, which is the reason PD-1 antibodies were tried. ORIENT-4 was a single-arm, multicentre phase 2 study in China that gave the PD-1 antibody sintilimab, 200 mg intravenously every three weeks for up to 24 months, to 28 patients enrolled between August 2017 and February 2018 who had failed at least one asparaginase-based regimen.

Twenty-one of the 28 (75.0 per cent, 95 per cent confidence interval 55.1 to 89.3) had an objective response by the Lugano 2014 criteria. At a median follow-up of 30.4 months median overall survival had not been reached and two-year overall survival was 78.6 per cent. Most treatment-related adverse events were grade 1 or 2, the commonest a fall in the lymphocyte count; serious adverse events occurred in seven patients and none died of an adverse event.

It is one of the studies behind the statement on the entity page that PD-1 blockade has substantial activity in relapsed disease. It is small and uncontrolled.