Perspectives of traditional Chinese medicine to patch up immune checkpoint blockers.

Abstract

In this era of cancer immunotherapy, the response rates of immune checkpoint blockers (ICBs) are still too low and the adverse events may also be significant. Of the ways of patching up such deficits, chemotherapy (ChT), especially if metronomic, seems promising, especially as immunity induced by immunogenic cell death (ICD) may be preserved. However, side effects, e.g., lymphocytopenia and interstitial pneumonitis cannot be ignored; eventually, resistance may also ensue. Vascular endothelial growth factors (VEGFs), being potent angiogenic factors, promote cancer cells' purposeful angiogenesis rendering an extremely resistant tumor microenvironment (TME). This highly evasive and extremely resilient TME actually demands multi-agent, multi-target agents as currently in use through traditional Chinese medicine (TCM). With a good track record of 3,000 years, TCM is favored by mainland Chinese cancer patients. Although TCM had been criticized as unscientific and imprecise, recently, artificial intelligence (AI) technologies serve to elucidate the sound scientific basis and validity of TCM. Several TCM preparations having anti-VEGF actions are found; others suppress immune checkpoints. Especially, these herbs' multi-prong approach appears to be more effective than Western medicine's primarily monotherapy approach if one wishes to eradicate the very resistant TME. A "bonus" point is that some autoimmune-related adverse side effects of ICBs may also be reduced by TCM. Nevertheless, as the TCM experience is mostly anecdotal, robust clinical trials are mandatory. Moreover, other TCM problems, e.g., herbal batch variations and consistency and uniformity of herbal prescriptions are outstanding. Invariably, TCM prescriptions have daily variations as the practice of "syndrome differentiation" is hailed. Despite experienced TCM practitioners would refuse to give up their time-honored traditional practice, the multi-prong approach is still very attractive for the undue resilience of TME, let alone its good safety profile, ready availability, and eminent affordability. Although the passage is dark, light is now appearing at the end of the tunnel.