Pharmacokinetics, pharmacodynamics, safety and immunogenicity of recombinant, fully human anti-RANKL monoclonal antibody (MW031) versus denosumab in Chinese healthy subjects: a single-center, randomized, double-blind, single-dose, parallel-controlled trial.

BACKGROUND: MW031 is a biosimilar candidate of denosumab (Prolia®). This study aimed to compare the pharmacokinetics, pharmacodynamics, safety and immunogenicity of MW031 to denosumab in healthy Chinese participants. RESEARCH DESIGN AND METHODS: In this single-center, randomized, double-blind, parallel-controlled, single-dose trial, participants were given 60 mg MW031 (N = 58) or denosumab (N = 61) by subcutaneous injection and observed for 140 days. The primary endpoint was the bioequivalence of PK parameters (Cmax, AUC0-∞), and secondary endpoints including PD parameter, safety, and immunogenicity. RESULTS: A comparison of main PK parameters showed that the geometric mean ratios (GMR) (90% confidence intervals [CIs]) of AUC0-∞ and Cmax for MW031 over denosumab were 105.48% (98.96%, 112.43%) and 98.58% (92.78%, 104.75%), respectively. The inter-CV values of AUC0-∞ and Cmax for MW031 ranged from 19.9% to 23.1%. PD parameter (sCTX) in the MW031 and denosumab groups were similar, and the positivity rates of immunogenicity were 0% in both groups. This study also showed similar safety profiles in both groups, and there were no drug-related, high-incidence and previously unreported adverse reactions. CONCLUSION: This trial confirmed similar pharmacokinetic profiles of MW031 and denosumab in healthy male participants, and pharmacodynamic profile, immunogenicity and safety were comparable for both drugs. TRIAL REGISTRATION: NCT04798313; CTR20201149.

Chlamydia muridarum Induces Pathology in the Female Upper Genital Tract via Distinct Mechanisms.

Sexually transmitted infection with Chlamydia trachomatis may lead to fibrotic blockage in women's upper genital tracts, resulting in tubal infertility. Intravaginal inoculation with C. muridarum readily induces fibrotic blockage or hydrosalpinx in mice and is used for investigating C. trachomatis pathogenicity. Using this model in combination with an antibody depletion approach, we confirmed CD4+ T cell-mediated protective immunity and a CD8+ T cell-dependent pathogenic mechanism during chlamydial infection in C57BL/6J mice. However, when mice genetically deficient in CD8+ T cells were evaluated, we found, surprisingly, that these mice were still able to develop robust hydrosalpinx following C. muridarum infection, both contradicting the observation made in C57BL/6J mice and suggesting a pathogenic mechanism that is independent of CD8+ T cells. We further found that depletion of CD4+ T cells from CD8+ T cell-deficient mice significantly reduced chlamydial induction of hydrosalpinx, indicating that CD4+ T cells became pathogenic in mice genetically deficient in CD8+ T cells. Since depletion of CD4+ T cells both promoted chlamydial infection and reduced chlamydial pathogenicity in CD8+ T cell-deficient mice, we propose that in the absence of CD8+ T cells, some CD4+ T cells may remain protective (as in C57BL/6J mice), while others may directly contribute to chlamydial pathogenicity. Thus, chlamydial pathogenicity can be mediated by distinct host mechanisms, depending upon host genetics and infection conditions. The CD8+ T cell-deficient mouse model may be useful for further investigating the mechanisms by which CD4+ T cells promote chlamydial pathogenicity.