MC# 22-08 - A First-in-Human, Multicenter, Phase I/II, Open-Label Study of XTX101 Monotherapy and XTX101 and Pembrolizumab Combination Therapy in Patients with Advanced Solid Tumors

  • Agent(s): XTX101
  • Disease Type(s): Solid Tumor
  • Phase(s): I, II
  • Drug Classification(s): Immunotherapy, Monoclonal Antibody, Targeted Therapy
  • Molecular Target(s): CTLA4

Mechanism of Action

XTX101 targets and binds to CTLA-4 expressed on T cells and inhibits the CTLA-4-mediated downregulation of T-cell activation.  This leads to a cytotoxic T-lymphocyte (CTL)-mediated immune response against cancer cells, thereby killing cancer cells. 


In this study, the sponsor and investigators want to learn:

  • How much of XTX101 can be given with an acceptable level of side effects and in combination with pembrolizumab
  • The effects of XTX101 (good and bad) and in combination with pembrolizumab
  • How much of XTX101 is absorbed into the blood and how fast it is removed
Inclusion Criteria
  • Disease Criteria
    • Part 1A and 1C- Any histologically or cytologically confirmed solid tumor malignancy that is locally advanced or metastatic and has failed standard therapy, or standard therapy is not curative or available
    • Part 1B - Any histologically or cytologically confirmed solid tumor malignancy for which anti-PD-1 or anti-PD-L1 treatment is approved and has progressed on or after prior anti-PD-1 or anti-PD-L1 therapy
    • Part 2- histologically or cytologically confirmed unresectable or metastatic melanoma that has not been treated with prior anti-PD-1 or anti-PD-L1 therapy
  • ECOG performance status of 0 or 1
  • Adequate organ function
  • Part 2 only: measurable disease per iRECIST
Exclusion Criteria
  • Received prior treatment with anti-CTL-4 therapy
  • Received prior immune-checkpoint therapy and experienced Grade 3 or greater toxicity lasting greater than 6 weeks
  • Received prior systemic anticancer therapy within 4 weeks prior to study treatment
  • Received prior radiotherapy within 2 weeks prior to study treatment
  • Has a diagnosis of immunodeficiency
  • Has known malignancy (other than disease under study) that is progressing or has required active treatment within the past 3 years
  • Has an active autoimmune disease that has required systemic treatment in past 2 years, including the use of disease modifying agents, corticosteroids or immunosuppressive drugs
  • Has an active infection requiring systemic therapy within 4 weeks prior to study treatment
  • Has a history of severe hypersensitivity reaction (≥ Grade 3) to any study intervention and/or any of its excipients
  • Has a known psychiatric or substance abuse disorder that would interfere with the participant's ability to cooperate with the requirements of the study
  • Part 2 only: has ocular melanoma
  • Part 2 only: has received prior anti-PD-1/L-1 therapy


  • Dallas, TX - Mary Crowley Cancer Research - Medical City
More Info:

Contact Us About This Trial

Reach out to us by sharing your info in the form below or give us a call at 972-566-3000.

Re: MC# 22-08