Phase I/II Open Label Study Evaluating the Safety and Efficacy of Combining STAT3 Inhibition (TTI-101) With Anti-PD-1 Therapy (Pembrolizumab) in Patients With Recurrent or Metastatic (RM) Head and Neck Squamous Cell Carcinoma (HNSCC)

Primary Objectives: ‐ Objective (Phase I): Determine the phase II dose of TTI‐101 when used in combinationwith pembrolizumab in solid tumor patients. ‐ Objective (Phase II): Determine the overall response rate (ORR) and progression freesurvival (PFS) of the combination evaluated according to RECIST criteria.Secondary Objectives: ‐ Objective: Determine the overall survival in HNSCC patients treated with thecombination. ‐ Objective: Determine the rate of immune‐related severe adverse events (irSAEs) ofthe combination. ‐ Objective: Evaluate the safety of the combination in solid tumor patients. SecondaryEndpoint: Overall SAEs, SAEs resulting in death, discontinuation, dose reduction ordose interruption, frequency, and time to onset and severity of AEs.Exploratory Objectives:‐‐Objective: Determine the relationship between pharmacokinetics, pharmacodynamics,baseline and post‐treatment immune and tumor biomarkers and clinical responses inpatients treated with the combination.