Clinical implications of nintedanib pharmacokinetics in patients with pulmonary fibrosis.

BACKGROUND: Nintedanib is used to treat both idiopathic and progressive pulmonary fibrosis (IPF/PPF). Evidence of both an exposure-response relationship and an exposure-toxicity relationship has been found, suggesting the potential value of therapeutic drug monitoring (TDM). We aimed to define the therapeutic window of nintedanib in a real-world cohort. METHODS: Data from two clinical studies were pooled for this analysis. To quantify exposure to nintedanib, a population-pharmacokinetic (PK) model was developed. Associations between PK and decline in forced vital capacity (FVC) and diffusing capacity (DLCO) were performed using linear-mixed-effect models (LMEM). The exposure-toxicity relationship was evaluated using a Cox proportional hazards model. RESULTS: In total, 911 PK samples from 99 patients were used to develop the PK model. The LMEM with random slopes and intercepts included 517 pulmonary function tests (PFT) from 81 patients. The average administered nintedanib dose was associated with the rate of FVC decline (p=0.002). Per 50 mg decrease of daily dosage, the rate of FVC decline increased by 53.5 mL/year. Neither nintedanib exposure nor dose significantly affected DLCO decline and they were also not significantly associated with the occurrence of a dose-limiting toxicity (DLT). This may be explained by a large inter- and intrapatient variability in nintedanib PK. CONCLUSION: Nintedanib dose was significantly associated with FVC loss. However, no significant relationship between nintedanib exposure and the occurrence of DLTs was found in this real-world population, and no therapeutic window could be established. The findings in this study indicate that nintedanib is an unsuitable candidate for performing TDM.

Phospholipase A2 is a circulating mediator in typhoid fever.

Circulating proinflammatory mediators have not been found in studies on typhoid fever, although the patients suffer from a systemic disease with characteristic protracted fever. The 14-kDa group II extracellular phospholipase A2 (PLA2) is induced by interleukin-1 and tumor necrosis factor and may mediate some of the effects of these cytokines. Circulating PLA2 concentrations were measured in 12 typhoid fever patients on various days after admission and after recovery. On admission, mean concentrations of PLA2 were elevated (1444 +/- 1560 ng/mL) and decreased gradually and significantly to day 14 (55 +/- 48 ng/mL). patients with complicated disease had significantly higher PLA2 levels on admission. PLA2 was not produced in a lipopolysaccharide-stimulated whole blood culture, indicating that PLA2 originates from other types of cells. These data indicate that PLA2 may be a mediator of disease in protracted inflammatory diseases such as thyroid fever.