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Restore CFTR Protein Completed with Results
Phase 2 study of PTI-808 triple-combination therapy in adults with cystic fibrosis who have at least one copy of the F508del mutation (PTI-808-01 )
This study evaluated the effectiveness and safety of the drug, PTI-808 in combination with PTI-801, with or without PTI-428. This study was for people with CF ages 18 and older who have at least one copy of the F508del CFTR mutation.
This study had 3 main treatment groups. The doses tested in all groups were 300mg of PTI-808, 600mg of PTI-801, and 10mg of PTI-428. In group 1, participants were randomized to PTI-808 + PTI-801 + PTI-428, PTI-808 + PTI-801 + placebo matching PTI-428, or placebo for 28 days. In group 2, participants were randomized to either PTI-808 + PTI-801 + PTI-428 or placebo for 28 days. In group 3, participants were randomized to either PTI-808 + PTI-801 or placebo for 28 days.
Eligibility
See other primary eligibility criteria for more information.
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Age:
18 Years and Older -
Mutation(s):
Two Copies F508del or One Copy F508del -
FEV1% Predicted:
40 to 90%
For more information about the results of this study and where it was conducted, visit ClinicalTrials.gov.
Other Primary Eligibility Criteria
Participants must have at least one copy of the F508del mutation. In addition, they must not have taken CFTR modulator therapies (e.g., ivacaftor, lumacaftor, tezacaftor) for at least 14 days prior to screening.
Study Results
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What We Learned:
Initial results from this study found that participants with two copies of F508del CFTR mutation receiving PTI-808, PTI-801, and PTI-428 experienced an 8% improvement, as measured by absolute change in percent predicted FEV1 and a -29 mmol/L reduction in sweat chloride at day 28 when compared with placebo. PTI-808, PTI-801, and PTI-428 were generally well-tolerated.
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Primary Findings:
Effectiveness:
Safety:
Based on initial results from the study, 28 participants with two copies of F508del CFTR mutation and 40 participants with at least one copy of the F508del CFTR mutation were enrolled in the three groups. Results presented to date are for participants with two copies of F508del CFTR mutation.
PTI-808, PTI-801, and PTI-428 were generally well-tolerated. Participants who have two copies of the F508del CFTR mutation experienced an 8% improvement in lung function at day 28 (p≤ 0.01, 95% CI 3,12; n=11). The improvements seen in lung function were highest in participants with a baseline lung function measurement of <70% ppFEV1 (10%; n=9), those with at least 2 pulmonary exacerbations within the previous 12 months (12%, n=5), and poor responders to prior CFTR modulators (12%, n=7).
A reduction in sweat chloride was seen in participants who have two copies of the F508del CFTR mutation receiving PTI-808, PTI-801, and PTI-428 at day 28 (-29 mmol/L, p< 0.0005, 95% CL -42, -16; n=11) compared with placebo.
For comparison, the dual combination of PTI-801+ PTI-808 resulted in a 6.6% improvement in lung function and in a -13 mmol/L reduction in sweat chloride.
In participants with one copy of the F508del CFTR mutation, a smaller but statistically significant reduction in sweat chloride and non-significant improvement in FEV1 were seen.
These results have been provided from a Proteostasis Therapeutics press release and an NACFC abstract and have not been peer reviewed.
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Citation:
For current information about the overall development status of this drug, please check the Drug Development Pipeline.
Study Design
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Study Type: ?more info
Interventional -
Randomized Study: ?more info
Yes -
Placebo Controlled: ?more info
Yes -
Length of Participation:
10 weeks -
Number of Study Visits:
9
Additional Information
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Phase: ?more info
Phase Two -
Study Sponsor: ?more info
Proteostasis -
Study Drugs:
Eligibility
See other primary eligibility criteria for more information.
-
Age:
18 Years and Older -
Mutation(s):
Two Copies F508del or One Copy F508del -
FEV1% Predicted:
40 to 90%
For more information about the results of this study and where it was conducted, visit ClinicalTrials.gov.
Other Primary Eligibility Criteria
Participants must have at least one copy of the F508del mutation. In addition, they must not have taken CFTR modulator therapies (e.g., ivacaftor, lumacaftor, tezacaftor) for at least 14 days prior to screening.

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