First-in-human study of FAZ053, an anti-programmed death-ligand 1 (anti-PD-L1) monoclonal antibody, alone and in combination with spartalizumab, in patients with advanced malignancies.

BACKGROUND

FAZ053 triggers an antitumor response by targeting programmed death-ligand 1 (PD-L1), thereby activating effector T cells and negatively regulating T cells. This study assessed the safety, tolerability, and preliminary efficacy of FAZ053 monotherapy and in combination with spartalizumab in patients with advanced solid tumors.

METHODS

This phase I, multicenter, open-label study (NCT02936102) included dose escalation and dose expansion. The primary objectives were safety and tolerability; secondary objectives were pharmacokinetics, pharmacodynamics, and preliminary antitumor activity.

RESULTS

Of the 154 patients treated, 49 (52.7%) patients receiving FAZ053 monotherapy experienced at least one treatment-related adverse event (TRAE), of whom 6 (6.5%) experienced grade ≥3 TRAEs; 35 patients (57.4%) receiving combination therapy experienced TRAEs, of whom 3 (4.9%) experienced grade ≥3 TRAEs. One patient who received FAZ053 1600 mg every 6 weeks (Q6W) and one who received FAZ053 20 mg every 3 weeks (Q3W) with spartalizumab 300 mg Q3W experienced dose-limiting toxicities of grade 4 creatinine increase and grade 3 liver function test increased, respectively. The median duration of exposure was 105 days for monotherapy and 85 days for combination therapy. During dose escalation, response was observed in 3 (5.1%) and 3 (4.9%) patients receiving FAZ053 monotherapy and combination therapy, respectively. In dose expansion, response was observed in 2 (50%) patients with advanced alveolar soft part sarcoma (ASPS) and 3 (30%) patients with advanced chordoma receiving FAZ053 monotherapy. FAZ053 demonstrated a dose-proportional pharmacokinetic profile with a terminal half-life of 20.6 days at 1200 mg Q3W. Biomarker analysis showed increased immune gene expression following FAZ053 treatment. The recommended dose for expansion was 1200 mg Q3W.

CONCLUSION

FAZ053 monotherapy was well tolerated and effective in maintaining disease control in various tumors including ASPS and chordoma. The anticipated synergistic effect of combined programmed cell death protein 1 (PD-1) and PD-L1 inhibition was not observed. These findings contribute to the growing evidence that rare, phenotypically 'immune cold' sarcomas, such as ASPS and chordoma, can become responsive to immune checkpoint inhibitors.