A novel drug delivery platform has been developed that utilizes a naturally occurring receptor known as the neonatal Fc receptor (FcRn). The receptor is specific for the Fc fragment of IgG and is expressed in epithelial cells where it functions to transport immunoglobulins across these cell barriers. It has been shown that FcRn is expressed in both the upper and central airways in non-human primates as well as in humans. Pulmonary delivery of an erythropoietin- Fc fusion molecule (EpoFc) was previously demonstrated in non-human primates using this FcRn pathway. We have now conducted a phase I clinical study to test whether the FcRn pathway functioned similarly in man using human erythropoietin (Epo) fused to the Fc portion of human IgG1. The design was a three leg, non-randomized study conducted in healthy male volunteers with rising doses (3, 10, and 30 microg/kg) of the fusion protein targeted to the central lung regions. Using a target range of 10-30% vital capacity and 15 breaths per minute, approximately 70% of the lung-deposited dose of aerosolized EpoFc was delivered safely and effectively to the central lung regions. We showed dose-dependent concentrations of the fusion protein in the serum and an increase in circulating reticulocytes was evident in the highest dose group, thus demonstrating that large therapeutic molecules can be delivered to humans via the lung, with retention of biological activity, using the FcRn-mediated transport pathway.

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The goal of this exploratory pilot study was to use gamma scintigraphy to evaluate, under physiological conditions, disintegration profiles of encapsulated and nonencapsulated formulations of 100 mg sumatriptan. Using a crossover design, healthy volunteers (n = 10) ingested 100-mg doses of sumatriptan tablets radiolabeled with 111Indium, as well as encapsulated sumatriptan tablets that were prepared similarly, then placed within a gelatin capsule and backfilled with an excipient blend radiolabeled with 99mTechnetium. A gamma camera recorded scintigraphic images until 5 hours postdose. Initial disintegration of the gelatin capsule was observed at a mean (range) of 5 minutes (1-11 minutes); disintegration was complete within 14 minutes (5-24 minutes). For nonencapsulated versus encapsulated tablets, the mean (+/- standard deviation) time to initial disintegration (6 +/- 5 minutes vs 8 +/- 5 minutes) and time to complete disintegration (18 +/- 14 minutes vs 16 +/- 7 minutes) were comparable. Results of this study demonstrate that encapsulated and nonencapsulated sumatriptan have equivalent in vivo dissolution rates.

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