Primary ITP represents a prevalent acquired hemorrhagic disorder characterized by isolated thrombocytopenia [1]. IVIG has been accepted as one of the effective treatments for ITP in many guidelines [1, 11,12,13]. The immunomodulatory mechanisms of IVIG in ITP treatment are multifactorial, including: 1) Fc receptor blockade in splenic macrophages, preventing phagocytosis of antibody-opsonized platelets; 2) modulation of autoantibody production and binding capacity, coupled with inflammatory cytokine suppression; and 3) inhibition of complement-mediated platelet destruction.

While IVIG formulations are commercially available at various concentrations (typically 5% or 10%), only 5% preparations are currently marketed in China. This study investigates a novel, highly purified 10% IVIG formulation, which has received clinical trial authorization from the National Medical Products Administration (NMPA) for the treatment of persistent or chronic ITP [13].

In this study, 72.2% patients achieved platelet count ≥ 30 × 109/L and experienced a ≥ twofold increase from baseline after the initial investigational product administration within 7 days, which was similar to the other 10% IVIG reported by clinical trial [14,15,16,17]. The other 10% IVIG showed a response rate of 75.7% for GC5107A [14], 63.2% (95% CI: 46.0, 78.2) for IQYMUNE® [15], 52.9% (95% CI: 35.1, 70.2) for Yimmugo® [16], 80.7% (95% CI: 69.2, 89.3) for Privigen® [17], 80·6% (95 CI: 63·98, 91·81%) for Panzyga® [18], and so on. The median time to achieve platelet count ≥ 50 × 109/L, was 3 days, which was similar to the other 10% IVIG reported by clinical trial [17].

Safety analysis revealed that while 91.7% of patients experienced TEAEs, the majority were mild to moderate in severity. ADRs were reported in 51.4% of subjects, consistent with established safety profiles of other 10% IVIG formulations [17], with all events resolving without sequelae. Nine serious adverse events (SAEs) were documented, including one mortality case attributed to disease progression and subsequent massive gastrointestinal hemorrhage. Notably, the fatal event occurred approximately 3 months post-infusion, with no causal relationship to the investigational product, as evidenced by the subject's positive initial treatment response and absence of infusion-related adverse effects. The investigational 10% IVIG demonstrated favorable tolerability, with an adverse event profile comparable to existing IVIG products. The most frequently observed ADRs included headache (20.8%), pyrexia, leukopenia, and nausea, consistent with established safety data [18]. All headache events were mild and self-limiting, with severity and incidence rates within expected parameters.

Manufactured by Taibang Biological Ltd [19]. the investigational product undergoes rigorous viral safety measures, including low-temperature ethanol fractionation, caprylic acid precipitation, ion-exchange chromatography, low pH incubation, and pasteurization. Comprehensive viral safety was confirmed through serological testing, with all patients testing negative for HBsAg, anti-HCV, anti-HIV, and anti-Treponema pallidum antibodies pre- and post-treatment, and no reported viral transmissions [20].

This novel 10% IVIG formulation offers distinct pharmacokinetic advantages, including a 34% reduction in infusion time compared to standard 5% formulations while maintaining comparable therapeutic efficacy and safety profiles [19]. The established dosing regimen of 1 g/kg/day for two consecutive days demonstrated both clinical efficacy and favorable safety, supporting its therapeutic application in adult ITP management.

Based on the current findings, we hypothesize that a single-dose IVIG regimen (1 g/kg administered once) may demonstrate comparable therapeutic efficacy to the conventional two-dose regimen (2 × 1 g/kg over two days), as our phase III trial established that the novel 10% IVIG formulation exhibits comparable efficacy and safety profiles to existing IVIG therapies in adult primary ITP patients. The rationale for exploring a single-dose regimen is supported by IVIG's rapid immunomodulatory effects (typically within 24–48 h post-infusion), preliminary clinical evidence suggesting satisfactory therapeutic response in some patients with a single dose, and potential healthcare optimization through reduced hospitalization duration and treatment costs. However, a well-designed randomized controlled trial (RCT) comparing single-dose versus standard two-dose regimens is essential to establish non-inferiority or potential superiority of the simplified approach, with future investigations incorporating expanded multicenter participation to ensure robust implementation. If non-inferiority is established, the single-dose regimen could emerge as a more cost-effective and patient-friendly treatment paradigm, potentially influencing guideline updates and clinical practice, while demonstrating inferior efficacy would reinforce the necessity of the two-dose regimen as the standard of care for optimal platelet recovery.