A phase I study of the combination of atezolizumab, tiragolumab, and stereotactic body radiation therapy in patients with metastatic multiorgan cancer

Abstract

Background: Immunotherapy targeting the PD-1/PD-L1 pathway is a standard of care in a number of metastatic malignancies, but less than a fifth of patients are expected to respond to ICIs (Immune Checkpoint Inhibitors). In a clinical trial, combining the anti-TIGIT (T cell immunoreceptor with Ig and ITIM domains) Mab (monoclonal antibody) tiragolumab with atezolizumab improved outcomes in non-small cell lung cancer. In preclinical models, SBRT (Stereotactic Body Radiation Therapy) could increase expression levels of the inhibitory co-receptors TIGIT and PD-L1. We aim to assess the combination of tiragolumab with atezolizumab and SBRT in metastatic, previously treated by ICIs, non-small cell lung cancer, head and neck cancer, bladder cancer, and renal cell cancer.

Methods: This phase I study (ClinicalTrials.gov NCT05259319) will assess the efficacy and safety of the combination of atezolizumab with tiragolumab and stereotactic body radiation therapy in patients with histologically proven metastatic non-small cell lung cancer, renal cell cancer, bladder cancer, and head and neck cancer previously treated. First part: 2 different schedules of SBRT in association with a fixed dose of atezolizumab and tiragolumab will be investigated only with metastatic non-small cell lung cancer patients (cohort 1). The expansion cohorts phase will be a multicentric, open-label study at the recommended scheme of administration and enroll additional patients with metastatic bladder cancer, renal cell cancer, and head and neck cancer (cohort 2, 3 and 4). Patients will be treated until disease progression, unacceptable toxicity, intercurrent conditions that preclude continuation of treatment, or patient refusal in the absence of progression or intolerance. The primary endpoint of the first phase is the safety of the combination in a sequential or concomitant scheme and to determine the expansion cohorts phase recommended scheme of administration. The primary endpoint of phase II is to evaluate the efficacy of tiragolumab + atezolizumab + SBRT in terms of 6-month PFS (Progression-Free Survival). Ancillary analyses will be performed with peripheral and intratumoral immune biomarker assessments.

Trial registration: This study is registered on ClinicalTrials.gov: NCT05259319, since February 28th, 2022.

Keywords: Atezolizumab; Bladder cancer; Head and neck cancer; Immunotherapy; Non-small cell lung cancer; PDL-1; Renal cell cancer; SBRT; Stereotactic body radiation therapy; TIGIT; Tiragolumab.

Fig. 1

Rationale: SBRT induces immunogenic cell death, which promotes TAAs and/or TNAs uptake by DCs. Then DCs migrate into the DLN in order to prime naive T cells. After activation in the DLN, CD8 T cells join irradiated and non-irradiated lesions to perform their anti-tumor immune function. CD8 T cell: CD8 T lymphocyte; DC: dendritic cell; DLN: draining lymph node; PD-L1: programmed death-ligand 1; PVR: poliovirus receptor; SBRT: stereotactic body radiation therapy; TAA: tumor-associated antigen; TNA: tumor neoantigen; TIGIT: T cell immunoreceptor with Ig and ITIM domains

Fig. 2

Study design. Sequential schedule (top panel), concomitant schedule (bottom panel)

Fig. 3

Decision diagram. Algorithm for assessment of sequential schedule (left panel) and concomitant schedule (right panel)