CLINICAL PHARMACOLOGY
Mechanism Of Action
Ivacaftor is a potentiator of
the CFTR protein. The CFTR protein is a chloride channel present at the surface
of epithelial cells in multiple organs. Ivacaftor facilitates increased
chloride transport by potentiating the channel open probability (or gating) of
CFTR protein located at the cell surface. The overall level of
ivacaftor-mediated CFTR chloride transport is dependent on the amount of CFTR
protein at the cell surface and how responsive a particular mutant CFTR protein
is to ivacaftor potentiation.
CFTR Chloride Transport Assay In
Fisher Rat Thyroid (FRT) Cells Expressing Mutant CFTR
In order to evaluate the
response of mutant CFTR protein to ivacaftor, total chloride transport was
determined in Ussing chamber electrophysiology studies using a panel of FRT
cell lines transfected with individual CFTR mutations. Ivacaftor increased
chloride transport in FRT cells expressing CFTR mutations that result in CFTR protein
being delivered to the cell surface.
Data shown in Figure 1 are the
mean (n=3-7) net change over baseline in CFTR-mediated chloride transport
following the addition of ivacaftor in FRT cells expressing mutant CFTR
proteins. The in vitro CFTR chloride response threshold was designated as a net
increase of at least 10% of normal over baseline (dotted line) because it is
predictive or reasonably expected to predict clinical benefit. Mutations with
an increase in chloride transport of 10% or greater are considered responsive.
A patient must have at least one CFTR mutation responsive to ivacaftor to be
indicated.
Mutations including F508del
that are not responsive to ivacaftor potentiation, based on the in vitro CFTR
chloride response threshold, are listed in Figure 1 below the dotted line.
Figure 1: Net Change Over Baseline (% of Normal) in
CFTR-Mediated Chloride Transport Following Addition of Ivacaftor in FRT Cells
Expressing Mutant CFTR (Ussing Chamber Electrophysiology Data)
* Clinical data exist for these mutations [see Clinical
Studies].
# A46D, G85E, E92K, P205S, R334W, R347P, T338I, S492F, I507del, V520F, A559T,
R560S, R560T, A561E, L927P, H1054D, G1061R, L1065P, R1066C, R1066H, R1066M,
L1077P, H1085R, M1101K, W1282X, N1303K mutations in the CFTR gene do not meet
the threshold of change in CFTR-mediated chloride transport of at least 10% of
normal over baseline.
Note that splice mutations
cannot be studied in this FRT assay and are not included in Figure 1. Evidence
of clinical efficacy exists for non-canonical splice mutations 2789+5G→A,
3272-26A→G, 3849+10kbC→T, 711+3A→G and E831X and these are
listed in Table 3 below [see also Clinical Studies]. The G970R mutation
causes a splicing defect resulting in little-to-no CFTR protein at the cell
surface that can be potentiated by ivacaftor [see Clinical Studies].
Ivacaftor also increased
chloride transport in cultured human bronchial epithelial (HBE) cells derived
from CF patients who carried F508del on one CFTR allele and either G551D
or R117H-5T on the second CFTR allele.
Table 3 lists mutations that
are responsive to ivacaftor based on 1) a positive clinical response and/or 2) in
vitro data in FRT cells indicating that ivacaftor increases chloride transport
to at least 10% over baseline (% of normal).
Table 3: List of CFTR Gene Mutations that Produce CFTR
Protein and are Responsive to KALYDECO
E56K |
G178R |
S549R |
S977F |
F1074L |
2789+5G→A |
P67L |
E193K |
G551D |
F1052V |
D1152H |
3272-26A→G |
R74W |
L206W |
G551S |
K1060T |
G1244E |
3849+10kbC→T |
D110E |
R347H |
D579G |
A1067T |
S1251N |
|
D110H |
R352Q |
711+3A→G |
G1069R |
S1255P |
|
R117C |
A455E |
E831X |
R1070Q |
D1270N |
|
R117H |
S549N |
S945L |
R1070W |
G1349D |
|
Pharmacodynamics
Sweat Chloride Evaluation
Changes in sweat chloride (a biomarker) response to KALYDECO were evaluated in
seven clinical trials [see Clinical Studies]. In a two-part, randomized,
double-blind, placebo-controlled, crossover clinical trial in patients with CF
who had a G1244E, G1349D, G178R, G551S, G970R, S1251N, S1255P, S549N, or S549R mutation
in the CFTR gene (Trial 4), the treatment difference in mean change in sweat
chloride from baseline through 8 weeks of treatment was -49 mmol/L (95% CI -57,
-41). The mean changes in sweat chloride for the mutations for which KALYDECO
is indicated ranged from -51 to -8, whereas the range for individual subjects
with the G970R mutation was -1 to -11 mmol/L. In an open-label clinical trial
in 34 patients ages 2 to less than 6 years administered either 50 mg or 75 mg
of ivacaftor twice daily (Trial 6), the mean absolute change from baseline in
sweat chloride through 24 weeks of treatment was -45 mmol/L (95% CI -53, -38) [see Use In Specific Populations]. In a randomized, double-blind,
placebo-controlled, 2-period, 3-treatment, 8-week crossover study in patients
with CF age 12 years and older who were heterozygous for the F508del mutation and with a second CFTR mutation predicted to be responsive to
ivacaftor (Trial 7), the treatment difference in mean change in sweat chloride
from study baseline to the average of Week 4 and Week 8 of treatment for
KALYDECO treated patients was -4.5 mmol/L (95% CI -6.7, -2.3). In a 24-week,
open-label clinical trial in patients with CF aged less than 24 months
administered either 25 mg, 50 mg or 75 mg of ivacaftor twice daily (Trial 8),
the mean absolute change from baseline in sweat chloride for patients aged 12
months to less than 24 months (n=10) was -73.5 mmol/L (95% CI -86.0, -61.0) at
Week 24, and the mean absolute change from baseline in sweat chloride for
patients aged 6 months to less than 12 months (n=6) was -58.6 mmol/L (95% CI
-75.9, -41.3) at Week 24. [see Use In Specific Populations].
There was no direct correlation between decrease in sweat
chloride levels and improvement in lung function (FEV1).
Cardiac Electrophysiology
The effect of multiple doses of ivacaftor 150 mg and 450
mg twice daily on QTc interval was evaluated in a randomized, placebo-and
active-controlled (moxifloxacin 400 mg) four-period crossover thorough QT study
in 72 healthy subjects. In a study with demonstrated ability to detect small
effects, the upper bound of the one-sided 95% confidence interval for the
largest placebo adjusted, baseline-corrected QTc based on Fridericia's
correction method (QTcF) was below 10 ms, the threshold for regulatory concern.
Pharmacokinetics
The pharmacokinetics of ivacaftor is similar between
healthy adult volunteers and patients with CF.
After oral administration of a single 150 mg dose to
healthy volunteers in a fed state, peak plasma concentrations (Tmax) occurred
at approximately 4 hours, and the mean (±SD) for AUC and Cmax were 10600 (5260)
ng*hr/mL and 768 (233) ng/mL, respectively.
After every 12-hour dosing, steady-state plasma
concentrations of ivacaftor were reached by days 3 to 5, with an accumulation
ratio ranging from 2.2 to 2.9.
Absorption
The exposure of ivacaftor increased approximately 2.5-to
4-fold when given with food that contains fat. Therefore, KALYDECO should be
administered with fat-containing food. Examples of fat-containing foods include
eggs, butter, peanut butter, cheese pizza, whole-milk dairy products (such as
whole milk, cheese, and yogurt), etc. The median (range) Tmax is approximately
4.0 (3.0; 6.0) hours in the fed state.
KALYDECO granules (2 x 75 mg) had similar bioavailability
as the 150 mg tablet when given with fat-containing food in adult subjects. The
effect of food on ivacaftor absorption is similar for KALYDECO granules and the
150 mg tablet formulation.
Distribution
Ivacaftor is approximately 99% bound to plasma proteins,
primarily to alpha 1-acid glycoprotein and albumin. Ivacaftor does not bind to
human red blood cells.
After oral administration of 150 mg every 12 hours for 7 days
to healthy volunteers in a fed state, the mean (±SD) for apparent volume of
distribution was 353 (122) L.
Metabolism
Ivacaftor is extensively metabolized in humans. In vitro and
clinical studies indicate that ivacaftor is primarily metabolized by CYP3A. M1
and M6 are the two major metabolites of ivacaftor in humans. M1 has
approximately one-sixth the potency of ivacaftor and is considered
pharmacologically active. M6 has less than one-fiftieth the potency of
ivacaftor and is not considered pharmacologically active.
Elimination
Following oral administration, the majority of ivacaftor
(87.8%) is eliminated in the feces after metabolic conversion. The major
metabolites M1 and M6 accounted for approximately 65% of the total dose
eliminated with 22% as M1 and 43% as M6. There was negligible urinary excretion
of ivacaftor as unchanged parent. The apparent terminal half-life was
approximately 12 hours following a single dose. The mean apparent clearance
(CL/F) of ivacaftor was similar for healthy subjects and patients with CF. The
CL/F (SD) for the 150 mg dose was 17.3 (8.4) L/hr in healthy subjects.
Specific populations
Pediatric Patients
The following conclusions about exposures between adults
and the pediatric population are based on population PK analyses:
Table 4: Ivacaftor Exposure by Age Group, Mean (SD)
Age Group |
Dose |
AUCSS (ng*h/mL) |
6 to less than 12 months (5 kg to <7 kg) * |
25 mg q12h |
5790 |
6 to less than 12 months (7 kg to <14 kg) |
50 mg q12h |
9250(3440) |
12 to less than 24 months (7 kg to <14 kg) |
50 mg q12h |
9050(3050) |
12 to less than 24 months (≥14 kg to <25 kg) |
75 mg q12h |
9600(1800) |
2 to less than 6 years (<14 kg) |
50 mg q12h |
10500(4260) |
2 to less than 6 years (>14 kg to <25 kg) |
75 mg q12h |
11300(3820) |
6 to less than 12 years |
150 mg q12h |
20000 (8330) |
12 to less than 18 years |
150 mg q12h |
9240(3420) |
Adults (≥18 years) |
150 mg q12h |
10700(4100) |
* Value based on data from a single patient; standard
deviation not reported |
Patients With Hepatic Impairment
Adult subjects with moderately
impaired hepatic function (Child-Pugh Class B, score 7-9) had similar ivacaftor
Cmax, but an approximately two-fold increase in ivacaftor AUC0-∞ compared
with healthy subjects matched for demographics. Based on simulations of these
results, a reduced KALYDECO dose to one tablet or packet of granules once daily
is recommended for patients with moderate hepatic impairment. The impact of
mild hepatic impairment (Child-Pugh Class A) on the pharmacokinetics of
ivacaftor has not been studied, but the increase in ivacaftor AUC0-∞ is
expected to be less than two-fold. Therefore, no dose adjustment is necessary
for patients with mild hepatic impairment. The impact of severe hepatic
impairment (Child-Pugh Class C, score 10-15) on the pharmacokinetics of
ivacaftor has not been studied. The magnitude of increase in exposure in these
patients is unknown, but is expected to be substantially higher than that
observed in patients with moderate hepatic impairment. When benefits are
expected to outweigh the risks, KALYDECO should be used with caution in
patients with severe hepatic impairment at a dose of one tablet or one packet
of granules given once daily or less frequently [see DOSAGE AND
ADMINISTRATION and Use In Specific Populations].
Patients With Renal impairment
KALYDECO has not been studied
in patients with mild, moderate, or severe renal impairment (creatinine
clearance less than or equal to 30 mL/min) or in patients with end-stage renal
disease. No dose adjustments are recommended for mild and moderate renal
impairment patients because of minimal elimination of ivacaftor and its
metabolites in urine (only 6.6% of total radioactivity was recovered in the
urine in a human PK study); however, caution is recommended when administering
KALYDECO to patients with severe renal impairment or end-stage renal disease.
Male And Female Patients
The effect of gender on
KALYDECO pharmacokinetics was evaluated using population pharmacokinetics of
data from clinical studies of KALYDECO. No dose adjustments are necessary based
on gender.
Drug Interaction Studies
Drug interaction studies were
performed with KALYDECO and other drugs likely to be co-administered or drugs
commonly used as probes for pharmacokinetic interaction studies [see DRUG
INTERACTIONS].
Dosing recommendations based on
clinical studies or potential drug interactions with KALYDECO are presented
below.
Potential For Ivacaftor To Affect
Other Drugs
Based on in vitro results,
ivacaftor and metabolite M1 have the potential to inhibit CYP3A and P-gp.
Clinical studies showed that KALYDECO is a weak inhibitor of CYP3A and P-gp,
but not an inhibitor of CYP2C8. In vitro studies suggest that ivacaftor and M1
may inhibit CYP2C9. In vitro, ivacaftor, M1, and M6 were not inducers of CYP
isozymes. Dosing recommendations for co-administered drugs with KALYDECO are
shown in Figure 2.
Figure 2: Impact of KALYDECO
on Other Drugs
Note: The data obtained with substrates but without
co-administration of KALYDECO are used as reference.
* NE: Norethindrone; ** EE: Ethinyl Estradiol
The vertical lines are at 0.8, 1.0, and 1.25, respectively.
Potential For Other Drugs To Affect
Ivacaftor
In vitro studies showed that ivacaftor and metabolite M1 were
substrates of CYP3A enzymes (i.e., CYP3A4 and CYP3A5). Exposure to ivacaftor is
reduced by concomitant CYP3A inducers and increased by concomitant CYP3A
inhibitors [see DOSAGE AND ADMINISTRATION and DRUG INTERACTIONS].
KALYDECO dosing recommendations for co-administration with other drugs are
shown in Figure 3.
Figure 3: Impact of Other Drugs on KALYDECO
Note: The data obtained for KALYDECO without co-administration of
inducers or inhibitors are used as reference. The vertical lines are at 0.8,
1.0, and 1.25, respectively.
Clinical Studies
Trials In Patients With CF Who
Have A G551D Mutation In The CFTR Gene
Dose Ranging
Dose ranging for the clinical
program consisted primarily of one double-blind, placebo-controlled, crossover
trial in 39 adult (mean age 31 years) Caucasian patients with CF who had FEV1 ≥40%
predicted. Twenty patients with median predicted FEV1 at baseline of 56%
(range: 42% to 109%) received KALYDECO 25, 75, 150 mg or placebo every 12 hours
for 14 days and 19 patients with median predicted FEV1 at baseline of 69%
(range: 40% to 122%) received KALYDECO 150, 250 mg, or placebo every 12 hours
for 28 days. The selection of the 150 mg every 12 hours dose was primarily
based on nominal improvements in lung function (pre-dose FEV1) and changes in
pharmacodynamic parameters (sweat chloride and nasal potential difference). The
twice-daily dosing regimen was primarily based on an apparent terminal plasma
half-life of approximately 12 hours.
Efficacy
The efficacy of KALYDECO in
patients with CF who have a G551D mutation in the CFTR gene was evaluated in
two randomized, double-blind, placebo-controlled clinical trials in 213
clinically stable patients with CF (109 receiving KALYDECO 150 mg twice daily).
All eligible patients from these trials were rolled over into an open-label
extension study.
Trial 1 evaluated 161 patients
with CF who were 12 years of age or older (mean age 26 years) with FEV1 at
screening between 40-90% predicted [mean FEV1 64% predicted at baseline (range:
32% to 98%)]. Trial 2 evaluated 52 patients who were 6 to 11 years of age (mean
age 9 years) with FEV1 at screening between 40-105% predicted [mean FEV1 84%
predicted at baseline (range: 44% to 134%)]. Patients who had persistent Burkholderia
cenocepacia, Burkholderia dolosa, or Mycobacterium abscessus isolated
from sputum at screening and those with abnormal liver function defined as 3 or
more liver function tests (ALT, AST, AP, GGT, total bilirubin) ≥3 times
the upper limit of normal were excluded.
Patients in both trials were
randomized 1:1 to receive either 150 mg of KALYDECO or placebo every 12 hours
with food containing fat for 48 weeks in addition to their prescribed CF
therapies (e.g., tobramycin, dornase alfa). The use of inhaled hypertonic
saline was not permitted.
The primary efficacy endpoint
in both studies was improvement in lung function as determined by the mean
absolute change from baseline in percent predicted pre-dose FEV1 through 24
weeks of treatment.
In both studies, treatment with
KALYDECO resulted in a significant improvement in FEV1. The treatment
difference between KALYDECO and placebo for the mean absolute change in percent
predicted FEV1 from baseline through Week 24 was 10.6 percentage points (P<0.0001)
in Trial 1 and 12.5 percentage points (P<0.0001) in Trial 2 (Figure
4). These changes persisted through 48 weeks. Improvements in percent predicted
FEV1 were observed regardless of age, disease severity, sex, and geographic
region.
Figure 4: Mean Absolute Change from Baseline in
Percent Predicted FEV1 *
* Primary endpoint was assessed
at the 24-week time point.
Other efficacy variables
included absolute change from baseline in sweat chloride [see CLINICAL
PHARMACOLOGY], time to first pulmonary exacerbation (Trial 1 only),
absolute change from baseline in weight, and improvement from baseline in
Cystic Fibrosis Questionnaire Revised (CFQ-R) respiratory domain score, a
measure of respiratory symptoms relevant to patients with CF such as cough,
sputum production, and difficulty breathing. For the purpose of the study, a
pulmonary exacerbation was defined as a change in antibiotic therapy (IV,
inhaled, or oral) as a result of 4 or more of 12 pre-specified sino-pulmonary
signs/symptoms. Patients treated with KALYDECO demonstrated statistically
significant improvements in risk of pulmonary exacerbations, CF symptoms (in
Trial 1 only), and gain in body weight (Table 5). Weight data, when expressed
as body mass index normalized for age and sex in patients <20 years of age,
were consistent with absolute change from baseline in weight.
Table 5: Effect of KALYDECO on Other Efficacy
Endpoints in Trials 1 and 2
|
Trial 1 |
Trial 2 |
Treatment differencea (95% CI) |
P value |
Treatment difference a (95% CI) |
P value |
Mean absolute change from baseline in CFQ-R respiratory domain score (points) |
Through Week 24 |
8.1 (4.7, 11.4) |
<0.0001 |
6.1 (-1.4, 13.5) |
0.1092 |
Through Week 48 |
8.6 (5.3, 11.9) |
<0.0001 |
5.1 (-1.6, 11.8) |
0.1354 |
Relative risk of pulmonary exacerbation |
Through Week 24 |
0.40 b |
0.0016 |
NA |
NA |
Through Week 48 |
0.46 b |
0.0012 |
NA |
NA |
Mean absolute change from baseline in body weight (kg) |
At Week 24 |
2.8 (1.8, 3.7) |
<0.0001 |
1.9 (0.9, 2.9) |
0.0004 |
At Week 48 |
2.7 (1.3, 4.1) |
0.0001 |
2.8 (1.3, 4.2) |
0.0002 |
Absolute change in sweat chloride (mmol/L) |
Through Week 24 |
-48 (-51, -45) |
<0.0001 |
-54 (-62, -47) |
<0.0001 |
Through Week 48 |
-48 (-51, -45) |
<0.0001 |
-53 (-61, -46) |
<0.0001 |
CI: confidence interval; NA: not analyzed due to low
incidence of events
a Treatment difference = effect of KALYDECO – effect of Placebo
b Hazard ratio for time to first pulmonary exacerbation |
Trial In Patients With A G1244E,
G1349D, G178R, G551S, G970R, S1251N, S1255P, S549N, Or S549R Mutation in the CFTR
Gene
The efficacy and safety of
KALYDECO in patients with CF who have a G1244E, G1349D, G178R, G551S, G970R, S1251N,
S1255P, S549N, or S549R mutation in the CFTR gene were evaluated in a two-part,
randomized, double-blind, placebo-controlled, crossover design clinical trial
in 39 patients with CF (Trial 4). Patients who completed Part 1 of this trial
continued into the 16-week open-label Part 2 of the study. The mutations
studied were G178R, S549N, S549R, G551S, G970R, G1244E, S1251N, S1255P, and G1349D.
See Clinical Studies for efficacy in patients with a G551D mutation.
Patients were 6 years of age or
older (mean age 23 years) with FEV1 ≥40% at screening [mean FEV1 at
baseline 78% predicted (range: 43% to 119%)]. Patients with evidence of
colonization with Burkholderia cenocepacia, Burkholderia dolosa, or Mycobacterium
abscessus and those with abnormal liver function defined as 3 or more liver
function tests (ALT, AST, AP, GGT, total bilirubin) ≥3 times the upper
limit of normal at screening were excluded.
Patients were randomized 1:1 to
receive either 150 mg of KALYDECO or placebo every 12 hours with food
containing fat for 8 weeks in addition to their prescribed CF therapies during
the first treatment period and crossed over to the other treatment for the
second 8 weeks. The two 8-week treatment periods were separated by a 4- to
8-week washout period. The use of inhaled hypertonic saline was not permitted.
The primary efficacy endpoint
was improvement in lung function as determined by the mean absolute change from
baseline in percent predicted FEV1 through 8 weeks of treatment. Other efficacy
variables included absolute change from baseline in sweat chloride through 8
weeks of treatment [see CLINICAL PHARMACOLOGY], absolute change
from baseline in body mass index (BMI) at 8 weeks of treatment (including body
weight at 8 weeks), and improvement in CFQ-R respiratory domain score through 8
weeks of treatment. For the overall population of the 9 mutations studied,
treatment with KALYDECO compared to placebo resulted in significant improvement
in percent predicted FEV1 [10.7 through Week 8 (P<0.0001)], BMI [0.66 kg/m²at Week 8 (P<0.0001)], and CFQ-R respiratory domain score [9.6 through
Week 8 (P=0.0004)]; however, there was a high degree of variability of efficacy
responses among the 9 mutations (Table 6).
Table 6: Effect of KALYDECO for Efficacy Variables in
the Overall Populations and for Specific CFTR Mutations
Mutation (n) |
Absolute change in percent predicted FEV1 |
BMI (kg/m²) |
CFQ-R Respiratory Domain Score (Points) |
Absolute Change in Sweat Chloride (mmol/L) |
At Week 2 |
At Week 4 |
At Week 8 |
At Week 8 |
At Week 8 |
At Week 8 |
All patients (n=39)
Results shown as mean (95% CI) change from baseline KALYDECO vs. placebo-treated patients: |
|
8.3 (4.5, 12.1) |
10.0 (6.2, 13.8) |
13.8 (9.9, 17.6) |
0.66 † (0.34, 0.99) |
12.8 (6.7, 18.9) |
-50 (-58, -41) * |
Patients grouped under mutation types (n)
Results shown as mean (minimum, maximum) for change from baseline for KALYDECO-treated patients **: |
G1244E (5) |
11 (-5, 25) |
6 (-5, 13) |
8 (-1, 18) |
0.63 (0.34, 1.32) |
3.3 (-27.8, 22.2) |
-55 (-75, -34) |
G1349D (2) |
19 (5, 33) |
18 (2, 35) |
20 (3, 36) |
1.15 (1.07, 1.22) |
16.7 (-11.1, 44.4) |
-80 (-82, -79) |
G178R (5) |
7 (1, 17) |
10 (-2, 21) |
8 (-1, 18) |
0.85 (0.33, 1.46) |
20.0 (5.6, 50.0) |
-53 (-65, -35) |
G551S (2) |
0 (-5, 5) |
0.3 (-5, 6) |
3†† |
0.16 †† |
16.7 †† |
-68 †† |
G970R (4) |
7(1, 13) |
7 (1, 14) |
3 (-1, 5) |
0.48 (-0.38, 1.75) |
1.4 (-16.7, 16.7) |
-6 (-16, -2) |
S1251N (8) |
2 (-23, 20) |
8 (-13, 26) |
9 (-20, 21) |
0.73 (0.08, 1.83) |
23.3 (5.6, 50.0) |
-54 (-84, -7) |
S1255P (2) |
11 (8, 14) |
9 (5, 13) |
3 (-1, 8) |
1.62 (1.39, 1.84) |
8.3 (5.6, 11.1) |
-78 (-82, -74) |
S549N (6) |
11 (5, 16) |
8 (-9, 19) |
11 (-2, 20) |
0.79 (0.00, 1.91) |
8.8 (-8.3, 27.8) |
-74 (-93, -53) |
S549R (4) |
3 (-4, 8) |
4 (-4, 10) |
5 (-3, 13) |
0.53 (0.33, 0.80) |
6.9 (0.0, 11.1) |
-61††† (-71, -54) |
* n=36 for the analysis of absolute change in sweat
chloride.
** Statistical testing was not performed due to small numbers for individual
mutations.
† Result for weight gain as a component of body mass index was consistent with
BMI.
†† Reflects results from the one patient with the G551S mutation with data at
the 8-week time point.
††† n=3 for the analysis of absolute change in sweat chloride. |
Trial In Patients With CF Who
Have An R117H Mutation In The CFTR Gene
The efficacy and safety of KALYDECO in patients with CF
who have an R117H mutation in the CFTR gene were evaluated in a randomized,
double-blind, placebo-controlled, parallel-group clinical trial (Trial 5).
Fifty-nine of 69 patients completed 24 weeks of treatment. Two patients
discontinued and 8 patients did not complete treatment due to study
termination. Trial 5 evaluated 69 clinically stable patients with CF who were 6
years of age or older (mean age 31 years). Patients who were 12 years and older
had FEV1 at screening between 40-90% predicted, and patients who were 6-11
years of age had FEV1 at screening between 40-105% predicted. The overall mean
FEV1 was 73% predicted at baseline (range: 33% to 106%). The patients had well
preserved BMIs (mean overall: 23.76 kg/m²) and a high proportion were
pancreatic sufficient as assessed by a low rate of pancreatic enzyme
replacement therapy use (pancreatin: 11.6%; pancrelipase: 5.8%). Patients who
had persistent Burkholderia cenocepacia, Burkholderia dolosa, or Mycobacterium
abscessus isolated from sputum at screening, and those with abnormal liver
function defined as 3 or more liver function tests (ALT, AST, AP, GGT, total
bilirubin) ≥3 times the ULN, were excluded.
Patients were randomized 1:1 to
receive either 150 mg of KALYDECO (n=34) or placebo (n=35) every 12 hours with
food containing fat for 24 weeks in addition to their prescribed CF therapies.
The primary efficacy endpoint
was improvement in lung function as determined by the mean absolute change from
baseline in percent predicted FEV1 through 24 weeks of treatment. The treatment
difference for absolute change in percent predicted FEV1 through Week 24 was
2.1 percentage points (analysis conducted with the full analysis set which
included all 69 patients), and did not reach statistical significance (Table
7).
Other efficacy variables that
were analyzed included absolute change in sweat chloride from baseline through
Week 24, improvement in cystic fibrosis respiratory symptoms through Week 24 as
assessed by the CFQ-R respiratory domain score (Table 7), absolute change in
body mass index (BMI) at Week 24, and time to first pulmonary exacerbation. The
overall treatment difference for the absolute change from baseline in BMI at
Week 24 was 0.3 kg/m² and the calculated hazard ratio for time to
first pulmonary exacerbation was 0.93, which were not statistically
significant.
Statistically significant
improvements in clinical efficacy (FEV1, CFQ-R respiratory domain) were seen in
several subgroup analyses, and decreases in sweat chloride were observed in all
subgroups. The mean baseline sweat chloride for all patients was 70 mmol/L.
Subgroups analyzed included those based on age, lung function, and poly-T
status (Table 7).
Table 7: Effect of KALYDECO on Overall Population (Percent
Predicted FEV1, CFQ-R Respiratory Domain Score, and Sweat Chloride) and in
Relevant Subgroups Through 24 Weeks
Subgroup Parameter |
Study Drug ients |
Absolute Change through Week 24 *-All Randomized Patients |
% Predicted FEV1 (Percentage Points) |
CFQ-R Respiratory Domain Score (Points) |
Sweat Chloride (mmol/L) |
n |
Mean |
Treatment Difference (95% CI) |
n |
Mean |
Treatment Difference (95% CI) |
n |
Mean |
Treatment Difference (95% CI) |
R117H-AU Pat |
|
Placebo |
35 |
0.5 |
2.1 |
34 |
-0.8 |
8.4 |
35 |
-2.3 |
-24.0 |
|
KALYDECO |
34 |
2.6 |
(-1.1, 5.4) |
33 |
7.6 |
(2.2, 14.6) |
32 |
-26.3 |
(-28.0, -19.9) |
Subgroup by Age |
|
|
|
|
|
|
|
|
|
|
|
6-11 |
Placebo |
8 |
3.5 |
-6.3 |
7 |
-1.6 |
-6.1 |
8 |
1.0 |
-27.6 |
KALYDECO |
9 |
-2.8 |
(-12.0, -0.7) |
8 |
-7.7 |
(-15.7, 3.4) |
8 |
-26.6 |
(-37.2, -18.1) |
12-17 |
Placebo |
1 |
- |
- |
1 |
- |
- |
1 |
- |
- |
KALYDECO |
1 |
- |
- |
1 |
- |
- |
1 |
- |
- |
≥18 |
Placebo |
26 |
-0.5 |
5.0 |
26 |
-0.5 |
12.6 |
26 |
-4.0 |
-21.9 |
KALYDECO |
24 |
4.5 |
(1.1, 8.8) |
24 |
12.2 |
(5.0, 20.3) |
23 |
-25.9 |
(-26.5, -17.3) |
Subgroup by Poly-T Status † |
5T |
Placebo |
24 |
0.7 |
5.3 |
24 |
-0.6 |
15.3 |
24 |
-4.6 |
-24.2 |
KALYDECO |
14 |
6.0 |
(1.3, 9.3) |
14 |
14.7 |
(7.7, 23.0) |
13 |
-28.7 |
(-30.2, -18.2) |
7T |
Placebo |
5 |
-0.9 |
0.2 |
5 |
-6.0 |
5.2 |
5 |
3.9 |
-24.1 |
KALYDECO |
11 |
-0.7 |
(-8.1, 8.5) |
11 |
-0.7 |
(-13.0, 23.4) |
10 |
-20.2 |
(-33.9, -14.3) |
Subgroup by Baseline FEV1 % Predicted |
<70% |
Placebo |
15 |
0.4 |
4.0 |
15 |
3.0 |
11.4 |
15 |
-3.8 |
-25.5 |
KALYDECO |
13 |
4.5 |
(-2.1, 10.1) |
13 |
14.4 |
(1.2, 21.6) |
12 |
-29.3 |
(-31.8, -19.3) |
70-90% |
Placebo |
14 |
0.2 |
2.6 |
13 |
-3.6 |
8.8 |
14 |
-3.1 |
-20.0 |
KALYDECO |
14 |
2.8 |
(-2.3, 7.5) |
14 |
5.2 |
(-2.6, 20.2) |
14 |
-23.0 |
(-26.9, -12.9) |
>90% |
Placebo |
6 |
2.2 |
-4.3 |
6 |
-2.5 |
-0.7 |
6 |
1.0 |
-26.8 |
KALYDECO |
7 |
-2.1 |
(-9.9, 1.3) |
6 |
-3.2 |
(-10.4, 9.0) |
6 |
-25.9 |
(-39.5, -14.1) |
* MMRM analysis with fixed effects for treatment, age,
week, baseline value, treatment by week, and subject as a random effect
† (n=54) Poly-T status confirmed by genotyping |
Trial In Patients With CF
Heterozygous For The F508del Mutation And A Second Mutation Predicted To
Be Responsive To Ivacaftor
The efficacy and safety of
KALYDECO and an ivacaftor-containing combination product in 246 patients with
CF was evaluated in a randomized, double-blind,
placebo-controlled, 2-period, 3-treatment, 8-week crossover design clinical
trial (Trial 7). Mutations predicted to be responsive to ivacaftor were
selected for the study based on the clinical phenotype (pancreatic
sufficiency), biomarker data (sweat chloride), and in vitro responsiveness to
ivacaftor.
Eligible patients were
heterozygous for the F508del mutation with a second mutation predicted
to be responsive to ivacaftor. Of the 244 patients included in the efficacy
analysis, who were randomized and dosed, 146 patients had a splice mutation and
98 patients had a missense mutation, as the second allele. 156 patients
received KALYDECO and 161 patients received placebo. Patients were aged 12
years and older (mean age 35 years [range 12-72]) and had a percent predicted
FEV1 at screening between 40-90 [mean ppFEV1 at study baseline 62 (range: 35 to
94)]. Patients with evidence of colonization with organisms associated with a
more rapid decline in pulmonary status (e.g. Burkholderia cenocepacia,
Burkholderia dolosa, or Mycobacterium abscessus) and those with abnormal liver
function at screening were excluded. Abnormal liver function was defined as 2
or more liver function tests (ALT, AST, ALP, GGT) ≥3 times the upper
limit of normal or total bilirubin ≥2 times the upper limit of normal, or
a single increase in ALT/AST ≥5 times the upper limit of normal.
The primary efficacy endpoint
was the mean absolute change from study baseline in percent predicted FEV1 averaged
at Weeks 4 and 8 of treatment. The key secondary efficacy endpoint was absolute
change in CFQ-R respiratory domain score from study baseline averaged at Weeks
4 and 8 of treatment. For the overall population, treatment with KALYDECO
compared to placebo resulted in significant improvement in ppFEV1 [4.7 percent
points from study baseline to average of Week 4 and Week 8 (P<0.0001)] and
CFQ-R respiratory domain score [9.7 points from study baseline to average of
Week 4 and Week 8 (P<0.0001)]. Statistically significant improvements
compared to placebo were also observed in the subgroup of patients with splice
mutations and missense mutations (Table 8).
Table 8: Effect of KALYDECO for Efficacy Variables
Mutation (n) |
Absolute Change in percent predicted FEV1 *† |
Absolute Change in CFQ-R Respiratory Domain Score (Points) *§ |
Absolute Change in Sweat Chloride (mmol/L) *§ |
Splice mutations (n=94 for IVA and n=97 for PBO)
Results shown as difference in mean (95% CI) change from study baseline for KALYDECO vs. placebo-treated patients: |
|
5.4 (4.1, 6.8) |
8.5 (5.3, 11.7) |
-2.4 (-5.0, 0.3) |
By individual splice mutation (n). Results shown as mean (minimum, maximum) for change from study baseline for KALYDECO-treated patients |
2789+5G→A (28 ) |
5.1 (-7.1, 17.0) |
8.6 (-5.6, 27.8) |
0.4 (-7.5, 8.8) |
3272-26A→G (23) |
3.5 (-9.1, 16.0) |
8.0 (-11.1, 27.8) |
-2.3 (-25.0, 11.8) |
3849+10kBc→T (40) |
5.1 (-6.8, 16.2) |
7.5 (-30.6, 55.6) |
-4.6 (-80.5, 23.0) |
711+3A→G (2) |
9.2 (8.9, 9.6) |
-8.3 (-13.9,-2.8) |
-9.9 (-13.5, -6.3) |
E831X (1) |
7.1 (7.1, 7.1) |
0.0 (0.0, 0.0) |
-7.8 (-7.8, -7.8) |
Missense mutations (n=62 for IVA and n=63 for PBO)
Results shown as difference in mean (95% CI) change from study baseline for KALYDECO vs. placebo-treated patients: |
|
3.6 (1.9, 5.2) |
11.5 (7.5, 15.4) |
-7.8 (-11.2, -4.5) |
By individual missense mutation (n).
Results shown as mean (minimum, maximum) for change from study baseline for KALYDECO-treated patients |
D579G (2) |
13.3 (12.4, 14.1) |
15.3 (-2.8, 33.3) |
-30.8 (-36.0, -25.5) |
D1152H (15) |
2.4 (-5.0, 10.2) |
13.7 (-16.7, 50.0) |
-4.8 (-22.0, 3.0) |
A455E (14) |
3.7 (-6.6, 19.7) |
6.8 (-13.9, 33.3) |
7.5 (-16.8, 16.0) |
L206W (2) |
4.2 (2.5, 5.9) |
12.5 (-5.6, 30.6) |
3.9 (-8.3, 16.0) |
P67L (12) |
4.3 (-2.5, 25.7) |
10.8 (-12.5, 36.1) |
-10.5 (-34.8, 9.8) |
R1070W (1) |
2.9 (2.9, 2.9) |
44.4 (44.4, 44.4) |
0.3 (0.3, 0.3) |
R117C (1) |
3.5 (3.5, 3.5) |
22.2 (22.2, 22.2) |
-36.0 (-36.0, -36.0) |
R347H (3) |
2.5 (-0.6, 6.9) |
6.5 (5.6, 8.3) |
-19.2 (-25.8, -7.0) |
R352Q (2) |
4.4 (3.5, 5.3) |
9.7 (8.3, 11.1) |
-21.9 (-45.5, 1.8) |
S945L (9) |
8.8 (-0.2, 20.5) |
10.6 (-25.0, 27.8) |
-30.8 (-50.8, -17.3) |
S977F (1) |
4.3 (4.3, 4.3) |
-2.8 (-2.8, -2.8) |
-19.5 (-19.5, -19.5) |
* Average of Week 4 and 8 values
† Absolute change in ppFEV1 by individual mutations is an ad hoc analysis.
§ Absolute change in CFQ-R respiratory domain score and absolute change in
sweat chloride by mutation subgroups and by individual mutations are ad hoc
analyses. |
In an analysis of BMI at Week 8, an exploratory
end-point, patients treated with KALYDECO had a mean improvement of 0.28 kg/m² [95%
CI (0.14, 0.43)], 0.24 kg/m² [95% CI (0.06, 0.43)], and 0.35 kg/m² [95% CI (0.12,
0.58)] versus placebo for the overall, splice, and missense mutation
populations of patients, respectively.
Trial In Patients Homozygous For
The F508del Mutation In The CFTR Gene
Trial 3 was a 16-week,
randomized, double-blind, placebo-controlled, parallel-group trial in 140
patients with CF age 12 years and older who were homozygous for the F508del
mutation in the CFTR gene and who had FEV1 ≥40% predicted. Patients were
randomized 4:1 to receive KALYDECO 150 mg (n=112) every 12 hours or placebo
(n=28) in addition to their prescribed CF therapies. The mean age of patients
enrolled was 23 years and the mean baseline FEV1 was 79% predicted (range 40%
to 129%). As in Trials 1 and 2, patients who had persistent Burkholderia
cenocepacia, Burkholderia dolosa, or Mycobacterium abscessus isolated
from sputum at screening and those with abnormal liver function defined as 3 or
more liver function tests (ALT, AST, AP, GGT, total bilirubin) ≥3 times
the upper limit of normal were excluded. The use of inhaled hypertonic saline
was not permitted.
The primary endpoint was
improvement in lung function as determined by the mean absolute change from
baseline through Week 16 in percent predicted FEV1. The treatment difference
from placebo for the mean absolute change in percent predicted FEV1 through
Week 16 in patients with CF homozygous for the F508del mutation in the CFTR
gene was 1.72 percentage points (1.5% and -0.2% for patients in the KALYDECO
and placebo-treated groups, respectively) and did not reach statistical
significance (Table 9).
Other efficacy variables that
were analyzed included absolute change in sweat chloride from baseline through
Week 16, change in cystic fibrosis respiratory symptoms through Week 16 as
assessed by the CFQ-R respiratory domain score (Table 9), change in weight
through Week 16, and rate of pulmonary exacerbation. The overall treatment
difference for change from baseline in weight through Week 16 was -0.16 kg (95%
CI -1.06, 0.74); the rate ratio for pulmonary exacerbation was 0.677 (95% CI
0.33, 1.37).
Table 9: Effect of KALYDECO on Overall Population
(Percent Predicted FEV1, CFQ-R Respiratory Domain Score, and Sweat Chloride)
Through 16 Weeks
Subgroup Parameter |
Study Drug |
Absolute Change through Week 16 *- Full Analysis Set |
% Predicted FEV1 (Percentage Points) |
CFQ-R Respiratory Domain Score (Points) |
Sweat Chloride (mmol/L) |
n |
Mean |
Treatment Difference (95% CI) |
n |
Mean |
Treatment Difference (95% CI) |
n |
Mean |
Treatment Difference (95% CI) |
F508del homozygous |
|
Placebo |
28 |
-0.2 |
1.72 |
28 |
-1.44 |
1.3 |
28 |
0.13 |
-2.9 |
KALYDECO |
111 |
1.5 |
(-0.6, 4.1) |
111 |
-0.12 |
(-2.9, 5.6) |
109 |
-2.74 |
(-5.6, -0.2) |
* MMRM analysis with fixed effects for treatment, age
week, baseline value, treatment by week, and subject as a random effect |