Long-Term Nonclinical Pulmonary Safety Assessment of Afrezza, a Novel Insulin Inhalation Powder

Afrezza delivers inhaled insulin using the Gen2 inhaler for the treatment of patients with type 1 and type 2 Diabetes. Afrezza was evaluated in long-term nonclinical pulmonary safety studies in 2 toxicology species. Chronic inhalation toxicology studies in rat (26 weeks) and dog (39 weeks) and an inhalation carcinogenicity study in rats were conducted with Technosphere insulin (Afrezza) and with Technosphere alone as a vehicle control. Respiratory tract tissues were evaluated by histopathology and cells expressing proliferating cell nuclear antigen (PCNA) were quantified in lungs of rats. Microscopic findings in rats exposed to Afrezza were attributed to the Technosphere particle component, were confined to nasal epithelia, and consisted of eosinophilic globules and nasal epithelial degeneration. There were no Afrezza-related changes in pulmonary PCNA labeling indices in alveoli, large bronchioles, or terminal bronchioles. Microscopic findings in rats exposed to Technosphere particles included eosinophilic globules, mucus cell hyperplasia, and epithelial degeneration in the nasal cavities. PCNA labeling indices were increased in large bronchioles and terminal bronchioles but not in alveoli. There were no Technosphere particle-related findings in the dog study. Afrezza did not exhibit carcinogenic potential in the 2-year study in rats. These nonclinical inhalation studies support the use of Afrezza in humans over extended periods.

Technosphere insulin: defining the role of Technosphere particles at the cellular level

BACKGROUND

Technosphere Insulin (TI) is a novel inhalation powder for the treatment of diabetes mellitus. Technosphere Insulin delivers insulin with an ultra rapid pharmacokinetic profile that is distinctly different from all other insulin products but similar to natural insulin release. Such rapid absorption is often associated with penetration enhancers that disrupt cellular integrity.

METHODS

Technosphere Insulin was compared to a panel of known penetration enhancers in vitro using the Calu-3 lung cell line to investigate the effects of TI on insulin transport.

RESULTS

Measures of tight junction integrity such as transepithelial electrical resistance, Lucifer yellow permeability, and F-actin staining patterns were all unaffected by TI. Cell viability and plasma membrane integrity were also not affected by TI. In contrast, cells treated with comparable (or lower) concentrations of penetration enhancers showed elevated Lucifer yellow permeability, disruption of the F-actin network, reduced cell viability, and compromised plasma membranes.

CONCLUSIONS

These results demonstrate that TI is not cytotoxic in an in vitro human lung cell model and does not function as a penetration enhancer. Furthermore, TI does not appear to affect the transport of insulin across cellular barriers.