Long-Term Safety of Rituximab in Granulomatosis With Polyangiitis and in Microscopic Polyangiitis.

OBJECTIVE: The present study was undertaken to conduct a phase IV, open-label, prospective study to characterize the long-term safety of rituximab in a 4-year observational registry of adult patients with granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) within the US. METHODS: Patients initiating treatment with rituximab were evaluated every 6 months for up to 4 years. Outcomes included the incidence of serious adverse events (SAEs), infusion-related reactions (IRRs), and SAEs of specific interest, including serious infections, serious cardiac events, serious vascular events, and malignancies. RESULTS: Overall, 97 patients (72 with GPA and 25 with MPA) received rituximab through a median of 8 (range 1-28) infusions and were followed up for a median of 3.94 years (range 0.05-4.32 years). The estimated incidence rates (95% confidence interval [95% CI]) of serious infections, serious cardiac events, and serious vascular events were 7.11 (4.55-10.58), 5.03 (2.93-8.06), and 2.37 (1.02-4.67) per 100 patient-years (PYs), respectively. No IRRs or SAEs occurred within 24 hours of an infusion of rituximab. None of the 9 deaths reported (crude mortality rate 2.67 [95% CI 1.22-5.06] per 100 PYs) were considered to be related to use of rituximab. CONCLUSION: The safety profile of long-term treatment with rituximab in patients with GPA or MPA was consistent with that of rituximab administered for shorter durations and with rituximab's known safety profile in other autoimmune diseases for which it has received regulatory approval. These findings provide clinicians with long-term, practice-level safety data for rituximab in the treatment of GPA or MPA.

Quantitative measurement of delivery and gene silencing activities of siRNA polyplexes containing pyridylthiourea-grafted polyethylenimines.

The activity of synthetic interfering nucleic acids (siRNAs) relies on the capacity of delivery systems to efficiently transport nucleic acids into the cytosol of target cells. The pyridylthiourea-grafted 25KDa polyethylenimine (πPEI) is an excellent carrier for siRNA delivery into cells and it was extensively investigated in this report. Quantification of the siRNA-mediated gene silencing efficiency indicated that the πPEI specific delivery activity at the cell level may be measured and appears relatively constant in various cell lines. Delivery experiments assaying inhibitors of various entry pathways or concanamycin A, an inhibitor of the H(+)/ATPase vacuolar pump showed that the πPEI/siRNA polyplexes did not require any specific entry mode but strongly relied on vacuolar acidification for functional siRNA delivery. Next, πPEI polyplexes containing a siRNA targeting the transcription factor HIF-1α, known to be involved in tumor progression, were locally injected into mice xenografted with a human glioblastoma. A 55% reduction of the level of the target mRNA was observed at doses comparable to those used in vitro when the πPEI delivery activity was calculated per cell. Altogether, our study underscores the usefulness of "simple"/rough cationic polymers for siRNA delivery despite their intrinsic limitations. The study underscores as well as that bottom-up strategies make sense. The in vitro experiments can precede in vivo administration and be of high value for selection of the carrier with enhanced specific delivery activity and parallel other research aiming at improving synthetic delivery systems for resilience in the blood and for enhanced tissue-targeting capacity.