Pidotimod

Immune & Anti-Inflammatory

Also known as: 3-L-Pyroglutamyl-L-Thiaziolidine-4-Carboxylic Acid, Piglet, Pidotimod Oral

Synthetic Immunostimulant DipeptidesResearch phase: Post-marketing (Italy, China, others), multiple RCTsRegulatory: Approved in Italy, Greece, China, and several other countries for recurrent respiratory tract infections. Not FDA-approved. Available as oral tablets/solution. Rx drug in approved markets.

Mechanism

Pidotimod is a synthetic dipeptide immunostimulant approved in several European and Asian countries to reduce the frequency and severity of respiratory infections, particularly in children and elderly patients. It works by stimulating both innate and adaptive immunity — activating dendritic cells to better recognize pathogens, promoting Th1 immune responses, and enhancing the maturation and activity of T-cells. Clinical trials show it can reduce the number of respiratory infections per year by 40-50% when used preventively.

Technical detail

Pidotimod (3-L-pyroglutamyl-L-thiazolidine-4-carboxylic acid) is a synthetic dipeptide immunomodulator acting primarily on dendritic cells (DCs). Mechanism: (1) Upregulates DC maturation markers (CD83, CD86, HLA-DR), enhancing antigen presentation capacity; (2) Stimulates DC production of IL-12 and IFN-α, driving Th1 polarization; (3) Enhances T-cell proliferation and IL-2 production; (4) Increases NK cell cytotoxicity; (5) Upregulates TLR2 and TLR4 expression on innate immune cells, improving pathogen recognition; (6) Stimulates phagocytic activity of macrophages. Meta-analysis of 29 RCTs (Niu et al., 2019) in pediatric recurrent respiratory infections: significantly reduced infection episodes (RR 0.59), antibiotic use, and symptom duration. Oral bioavailability ~45%. Well-tolerated safety profile across pediatric and geriatric populations.

Evidence