Small molecule inhibitors for cancer immunotherapy and associated biomarkers - the current status

Area of Science:

• Oncology
• Immunology
• Pharmacology

Background:

• Cancer immunotherapy has seen success with large molecules targeting immune checkpoints.
• Small molecules offer a new approach by targeting intracellular negative regulators of anti-tumor immunity.
• These regulators are found in both adaptive and innate immune cells, as well as the tumor microenvironment.

Purpose of the Study:

• To review the status of promising small molecule drug candidates for cancer immunotherapy.
• To discuss the potential of relevant biomarkers for these therapies.
• To highlight the development of small molecules targeting intracellular immune regulation.

Main Methods:

• Review of preclinical and clinical data for small molecule inhibitors.
• Identification of key intracellular targets in immune signaling pathways.
• Analysis of drug candidates targeting T cell receptor signaling, co-receptor signaling, cytokine signaling, cGAS/STING pathway, adenosine signaling, and prostaglandin E signaling.

Main Results:

• Several small molecule inhibitors targeting negative regulators of T cell signaling (e.g., MAP4K1, CBL-B, PTPN2) are in early clinical trials.
• Inhibitors of ENPP1 and TREX1 are in clinical development for enhancing innate anti-tumor immunity.
• CD39/CD73 inhibitors and EP2/EP4 antagonists are being investigated to counteract immunosuppressive signals.
• Most candidates are in the early stages of development.

Conclusions:

• Small molecules represent a promising frontier in cancer immunotherapy, targeting diverse intracellular mechanisms.
• Further development and biomarker identification are crucial for the success of these novel agents.
• These therapies aim to overcome limitations of current immunotherapies by modulating immune responses directly within cells and the tumor microenvironment.