PDCD1 and small cell lung carcinoma: For instance, sabatolimab (MBG453), a humanized IgG4 mAb, when combined with the anti-PD-1 mAb spartalizumab in a phase I study (NCT02608268), demonstrated a partial response rate of only 6% across a mixed cohort of advanced solid tumors, including CRC, NSCLC, malignant perianal melanoma, and small-cell lung cancer (SCLC) [47].