Using an initial prime-only DT6606 in vivo study (injections on days 0, 2 and 4 following tumor growth to 100 mm3), we determined that the addition of α-PD1 administration improved the antitumor efficacy of the regime, but tumors began to re-grow from day 19 (online supplemental figure S6E). The gene discussed is PDCD1; the disease is neoplasm.