Active Comparator Study | CAYSTON® (aztreonam for inhalation solution)

Exploring CAYSTON results compared to Tobramycin Inhalation Solution (TOBI)

The goal of the study was to look at 2 approved medications, CAYSTON and TOBI, by tracking changes in FEV1 in people with cystic fibrosis (CF) taking CAYSTON or TOBI over 3 treatment courses.

The study looked at FEV1 scores in 2 different ways:

  • Superiority analysis: Looks to see if results from 1 medication are better than results from the other
  • Non-inferiority analysis: Looks to see if results from 1 medication are not worse than results from the other

Who was in the study?

268 people age 6+ diagnosed with CF and Pseudomonas aeruginosa (Pa), with a starting FEV1 of 25%–75%.
136 people took CAYSTON* 3x a day during each 28-day treatment course
132 people took TOBI* 2x a day during each 28-day treatment course
* As instructed in the full Prescribing Information.

This was an open-label study. x That means people in the study knew which treatment they were getting and the researchers knew which treatment they were giving, which may influence the results. Additionally, people who took CAYSTON who had experience taking TOBI may have been more likely to report improvements in respiratory symptoms or treatment satisfaction with CAYSTON than with TOBI.

How long was the study?

  • The study lasted 26 weeks
  • Three courses of treatment, each lasting 28 days, were given
  • One treatment course consists of 28 days, followed by 28 days off treatment

The Active Comparator data are not included in the CAYSTON full Prescribing Information.

HOW DID CAYSTON COMPARE TO TOBI: SUPERIORITY ANALYSIS† x Superiority analysis looks to see if the results from 1 medication are better than results from the other.

2.70% difference in actual change in lung function across 3 treatment courses
CAYSTON Compared to TOBI: Superiority Chart
† Actual change in FEV1% predicted is the difference between the 2 results, shown as a percentage.
How to read this chart
Click the arrow to learn more. As you click, the chart will highlight. Swipe left to learn more. As you swipe, the chart will highlight.
There were 3 courses of treatment in this study.
1 course of treatment = 28 days on treatment followed by 28 days off treatment.
These numbers show the weeks that FEV1 was measured.
The actual change in FEV1 predicted throughout the study.
Superiority analysis looked at the average of 3 courses to see if the results from 1 medication were better than results from the other.
The results at Week 4, 12, and 20, were averaged together to understand the difference between CAYSTON and TOBI.
A point above 0 means lung function increased from baseline.
A point below 0 means lung function decreased from baseline.

How was this calculated?

FEV1 was tested at Week 4, Week 12, and Week 20. On average, the change from baseline in FEV1% was 2.70% higher for those taking CAYSTON compared to those taking TOBI over 3 treatment cycles.

Ask your doctor what these results may mean for you

HOW DID CAYSTON COMPARE TO TOBI: NON-INFERIORITY ANALYSIS‡ x Non-inferiority analysis looks to see if the results from 1 medication are not worse than the results from the other.

7.80% difference in relative change in lung function after 1 treatment course
CAYSTON Compared to TOBI: Non-Inferiority Chart
‡ Relative change in FEV1% predicted is the difference between 2 results, shown as a percentage.
How to read this chart
Click the arrow to learn more. As you click, the chart will highlight. Swipe left to learn more. As you swipe, the chart will highlight.
There were 3 courses of treatment in this study.
1 course of treatment = 28 days on treatment followed by 28 days off treatment.
These numbers show the weeks that FEV1 was measured.
The relative change in FEV1 predicted throughout the study.
Non-inferiority analysis looked at Week 4 to determine if results from 1 medication were not worse than results from the other.
A point above 0 means lung function increased from baseline.
A point below 0 means lung function decreased from baseline.

How was this calculated?

FEV1 was tested at Week 4. On average, the relative change from baseline in FEV1% was 7.80% higher for those taking CAYSTON compared to those taking TOBI.

Ask your doctor what these results may mean for you

Common side effects

During the Active Comparator study, at least 10% of people noticed the following side effects:

Common Side Effects Chart

Serious adverse events experienced by 22 people taking CAYSTON (16.2%) and 11 people taking TOBI (8.3%) most commonly included cough (CAYSTON: n=7/22; TOBI: n=4/11) and productive cough (CAYSTON: n=4/22; TOBI: n=5/11).

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