But now for the caveat. While providing a promise of improved aerosol technology, the article by Geller and colleagues also demonstrates the challenges that will be faced in improving the delivery of aerosolized therapies to individuals with CF. First, further advances in aerosol technology are still required. The AeroDose inhaler is not currently available, nor is it ready for widespread use by individuals with CF. Ten of the 53 participants in the study experienced a malfunction of the AeroDose inhaler. These malfunctions required that the study design be altered to allow a new AeroDose inhaler to be used for each tobramycin dose. Future studies of the AeroDose inhaler will need to demonstrate reliability along with improved efficacy of drug delivery. Second, aerosol delivery devices may require custom design for specific CF medications. An AeroDose inhaler can hold only one third of the 90-mg TSI dose, which would require stopping twice to refill the inhaler. A reconfiguration of the AeroDose inhaler from its current design would be needed to take full advantage of the potential time savings of using AeroDose technology to deliver tobramycin. Last, creative combinations of research funding from the National Institutes of Health, private foundations, and industry will be required to fully develop customized inhaled drug delivery systems for patients with CF. As opposed to COPD or asthma patients, the 30,000 individuals with CF in the United States are unlikely to provide sufficient potential financial gain for most pharmaceutical companies to justify committing the resources to develop, test, and gain Food and Drug Administration approval for CF-specific, inhaled drug-delivery systems. Despite the potential of the AeroDose inhaler to improve the quality of life of individuals with CF, Chiron Corporation is likely to think long and hard before committing itself to the development of a delivery system that might not significantly increase sales and may actually encourage patients to split up their current single-dose, 300-mg TSI vials into three 90-mg doses.