Comparison of Antibiotics Finds Cayston Best for Treating CF Pseudomonas Infections

Cayston (aztreonam) was deemed the best treatment across a range of parameters in a study comparing inhaled antibiotic treatments against Pseudomonas  (P.) aeruginosa lung infections in patients with cystic fibrosis (CF). But the study also demonstrated that Quinsair (levofloxacin inhalation solution) came in as a good second, improving lung function better than Cayston in the long run.

The study, “Comparison of Inhaled Antibiotics for the Treatment of Chronic Pseudomonas aeruginosa Lung Infection in Patients With Cystic Fibrosis: Systematic Literature Review and Network Meta-Analysis,” was published in the journal Clinical Therapeutics.

Quinsair is the latest addition to the group of inhaled antibiotics for chronic infections of P. aeruginosa in CF (the drug is approved in Europe, but not in the U.S. at this time). To compare its efficacy to the other drugs on the market, researchers at Queen’s University Belfast in the U.K. and Raptor Pharmaceuticals (now acquired by Horizon Pharma) performed an analysis of previously published studies.

They compared Quinsair to colistimethate sodium (brandnames ColoBeathe, Colomycin, and Promixin), Tobi (tobramycin inhaled solution), Tobi Podhaler (tobramycin inhaled powder), and Cayston.

Researchers identified seven studies that explored the effects of inhaled antibiotics after four weeks of treatment, and nine studies that looked at a 24-week treatment period.

The study collected information about percent predicted forced expiratory volume in one second (FEV1; a measure of lung function), the density of P. aeruginosa in sputum, changes in CF questionnaire–revised (CFQ-R — a tool measuring a treatment’s impact on overall health, daily life, perceived well-being and symptoms), and respiratory symptoms scores.

Hospitalization rates, the use of additional inhalation antibiotics, and study withdrawals for any reason — whether lack of treatment efficacy or for side effects, were also investigated. Not all of these measures were reported in all included studies.

Cayston, when given three times a day, was the only drug that was better than placebo in improving overall health after four weeks of treatment, measured by the CFQ-R. Only one study reported values after 24 weeks of treatment. That study, which compared Quinsair with Tobi, found that Quinsair tended to be better, although the result was not statistically significant.

Comparing drugs after four weeks of treatment, Cayston provided the numerically greatest improvements in percent predicted FEV1, followed by Quinsair. Quinsair was significantly better than placebo across the studies, while the effectivity values for the other drugs overlapped with that of placebo.

At 24 weeks, Quinsair outperformed all the other drugs in percent predicted FEV1. Also, patients taking the other drugs were more likely to be hospitalized than patients using Quinsair.

Compared with Quinsair, Tobi was linked to the highest risk of needing additional antibiotics at four weeks, while Cayston users had the lowest risk of needing additional medications. Although Quinsair had a slightly higher risk compared to Cayston, the difference between the two was not significant. Similar results were found after 24 weeks of treatment.

The amount of P. aeruginosa in patients’ sputum after treatment was similar in all the studied groups, as were study withdrawal rates.

Nevertheless, Cayston had the highest likelihood of being the best treatment across the different comparisons, followed by Quinsair. Cayston was FDA approved as an inhalation therapy for CF patients with P. aeruginosa infections in 2010.

“Because patients with CF with chronic P. aeruginosa infections frequently require changes in treatment, the availability of LIS [Quinsair (levofloxacin inhalation solution)] provides a useful option to preserve respiratory function over a longer period of time,” the research team concluded.