Tezacaftor/Ivacaftor in Subjects with Cystic Fibrosis and F508del/F508del-CFTR or F508del/G551D-CFTR

Scott H. Donaldson1, Joseph M. Pilewski2, Matthias Griese3, Jon Cooke4, Lakshmi Viswanathan5, Elizabeth Tullis6, Jane C. Davies7, Julie A. Lekstrom-Himes8, and Linda T.

Wang8; on behalf of the VX11-661-101 Study Group

1University of North Carolina School of Medicine, Chapel Hill, NC, United States; 2University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; 3Ludwig-Maximilians-University, Dr. von Hauner Children’s Hospital, Department of Pediatric Pneumology, Munich, Germany;

4Formerly of Vertex Pharmaceuticals (Europe) Limited, London, United Kingdom; 5Vertex Pharmaceuticals Incorporated, Boston, MA, United States; 6St. Michael’s Hospital and Keenan

Research Centre of Li Ka Shing Knowledge Institute, University of Toronto, Toronto, ON, Canada; 7Paediatric Respiratory Medicine, Imperial College & Royal Brompton and Harefield

Foundation Trust, London, United Kingdom; 8Vertex Pharmaceuticals (Europe) Limited, London, United Kingdom

Corresponding author: Linda T. Wang50 Northern AvenueBoston, MA 02210Office: 617-961-5029Fax: 617-366-3918Email: Linda_Wang@vrtx.com

Journal target: Am J Respir Crit Care Med

Author contributions: All authors were involved in data interpretation and the preparation, review, and approval of the manuscript.

Sources of support: This study was funded by Vertex Pharmaceuticals Incorporated.

Running title (50 characters max including spaces; current: 48): TEZ/IVA in Subjects with CF and F508del or G551D

Word count (max 3500): 3868

Descriptor number: 9.1 Adult Cystic Fibrosis

At a glance commentary (200 word max; current = 165):

Scientific Knowledge on the Subject: The most common mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene is F508del, which causes independent defects in processing and trafficking that reduce the amount of protein on the cell membrane while also disrupting channel gating. In contrast, the G551D mutant protein trafficks, but does not gate normally. Ivacaftor is a CFTR potentiator that increases chloride transport and improves lung function in patients with CFTR gating mutations. Tezacaftor (formerly VX-661) is a novel corrector that increases processing and trafficking of CFTR to the cell membrane. In combination, tezacaftor and ivacaftor have been shown to enhance CFTR activity in human bronchial epithelial cells homozygous for F508del and compound heterozygous for F508del and G551D.

What This Study Adds to the Field: We show that in the first clinical trial evaluating tezacaftor combined with ivacaftor, the combination has an acceptable safety profile, reduces sweat chloride, and improves lung function in subjects homozygous for F508del or compound heterozygous for F508del and G551D.

This article has an online data supplement, which is accessible from this issue’s table of contents online at www.atsjournals.org.

Abstract:

Rationale: Tezacaftor (formerly VX-661) is an investigational small molecule that improves

processing and trafficking of the cystic fibrosis transmembrane conductance regulator (CFTR)

in vitro, and improves CFTR function alone and in combination with ivacaftor.

Objectives: To evaluate safety and efficacy of tezacaftor monotherapy and

tezacaftor/ivacaftor combination therapy in subjects with CF homozygous for F508del or

compound heterozygous for F508del and G551D.

Methods: This was a randomized, placebo-controlled, double-blind, multicenter, phase 2 study

(NCT01531673). Subjects homozygous for F508del received tezacaftor (10 mg to 150 mg)

qday alone or in combination with ivacaftor 150 mg q12h in a dose escalation phase, as well

as in a dosage regimen testing phase. Subjects compound heterozygous for F508del and

G551D taking physician prescribed ivacaftor received tezacaftor 100 mg qday.

Measurements and Main Results: Primary endpoints were safety through day 56 and

change in sweat chloride from baseline through day 28. Secondary endpoints included change

in percent predicted FEV1 (ppFEV1) from baseline through day 28 and pharmacokinetics. The

incidence of adverse events was similar across treatment arms. Tezacaftor 100 mg

qday/ivacaftor 150 mg q12h resulted in a 6.04 mmol/L decrease in sweat chloride and 3.75

percentage point increase in ppFEV1 in subjects homozygous for F508del and a 7.02 mmol/L

decrease in sweat chloride and 4.60 percentage point increase in ppFEV1 in subjects

compound heterozygous for F508del and G551D from baseline through day 28 (P < 0.05 for

all).

Conclusions: These results support continued clinical development of tezacaftor 100 mg qday

in combination with ivacaftor 150 mg q12h in subjects with CF.

1

Clinical trial registered with www.ClinicalTrials.gov (NCT01531673).

Abstract word count (250 max): 255

Key words (3–5 [MeSH terms preferred]; do not use words from the title): Cystic fibrosis

transmembrane conductance regulator corrector; CFTR modulator; forced expiratory volume;

sweat chloride

Introduction

Cystic fibrosis (CF) affects an estimated 70,000 children and adults worldwide and is the most

common fatal genetic disease in persons of European descent (1). CF is caused by mutations

in the CF transmembrane conductance regulator (CFTR) gene that lead to a deficiency in the

amount and/or function of CFTR protein at the epithelial cell surface (2-4). Two complementary

approaches using CFTR modulators to increase CFTR-mediated chloride secretion in epithelia

have been studied (5). CFTR correctors modify the cellular processing and trafficking of the

CFTR protein to increase the amount of functional CFTR at the cell surface. CFTR potentiators

increase the channel gating activity of protein kinase A-activated CFTR at the cell surface to

enhance ion transport. Depending on the amount of residual CFTR channel activity in the

membrane and its functionality (reflecting the CFTR genotype of the patient and other factors),

both approaches may be required to effectively treat the clinical manifestations resulting from

defective CFTR-mediated chloride transport.

The most common CFTR mutation, F508del, is present on at least one allele in

approximately 87% of patients with CF who were entered into the US-based CF Foundation

Patient Registry and is on both alleles in approximately 46% (6). The F508del mutation causes

a processing and trafficking defect that reduces the amount of protein on the epithelial

membrane while also disrupting gating of the few channels that reach the surface; these

combined effects result in minimal CFTR-mediated chloride transport (7-10). Improving

chloride transport in patients homozygous for F508del requires combination therapy with both

a CFTR corrector, such as lumacaftor, and a CFTR potentiator (11-13).

3

Ivacaftor is an approved CFTR modulator for the treatment of patients with CF and at

least one of 33 CF- causing mutations (14), accounting for approximately 10% of all patients

with CF in the United States. It was first approved for patients with G551D (approximately 4%

of all patients with CF) or similar gating mutations (15-18) Most patients with G551D carry

F508del on their second allele. Both in vitro and clinical data support that the beneficial impact

of ivacaftor in those with a gating mutation is attributable to its effects on the gating allele (11).

Tezacaftor is a broad-acting CFTR corrector similar to lumacaftor that facilitates the cellular

processing and trafficking of normal CFTR and multiple mutant CFTR forms, including

F508del, thereby increasing the amount of CFTR protein at the cell surface, resulting in

increased chloride transport. The addition of a CFTR corrector to potentiator therapy provides

clinical benefit to those who carry processing and trafficking mutations such as F508del, the

most common CF-causing CFTR mutation (6). Additionally CFTR corrector and potentiator

combination therapy may provide benefit to patients who are compound heterozygous for

F508del and an ivacaftor-responsive mutation.

Tezacaftor is a new CFTR corrector currently being studied in clinical trials. Tezacaftor

in combination with ivacaftor has the potential to fill an important unmet need for CFTR

modulators, including improving the benefit-to-risk profile of CFTR modulation in patients

homozygous for F508del and enhancing the benefit of CFTR modulation for patients with

ivacaftor-responsive mutations. One of the important advantages of tezacaftor is that, unlike

lumacaftor, it is not an inducer of CYP3A4 enzymes (unpublished data) and does not interfere

with metabolism of ivacaftor or many other medications that are frequently used in CF,

reducing drug-drug interactions and dosing complexities (19). This phase 2, placebo-controlled

study evaluated the safety and efficacy of tezacaftor monotherapy and tezacaftor/ivacaftor

combination therapy in subjects with CF who were homozygous for F508del or compound

heterozygous for F508del and G551D.

Some of the results of these studies have been previously reported in the form of

abstracts (20-22).

Methods

Study Design

This was a randomized, placebo-controlled, double-blind, multicenter phase 2 study

(NCT01531673) using a multiple ascending dose and parallel-arm design that included a 28-

day treatment period followed by a 28-day post-treatment observation (washout) period. There

were 14 study arms as shown in the study schema (Figure 1). Because this was a proof-of-

concept study, each dose of tezacaftor was tested for tolerability as monotherapy before

testing in combination with ivacaftor during the dose escalation phase. Results across

treatment arms were assessed to evaluate dose response profiles and define dosing strategies

in subjects homozygous for F508del and to characterize safety and tolerability in subjects

homozygous for F508del or compound heterozygous for F508del and G551D.

Study Oversight

The protocol was reviewed and approved by the institutional review board or ethics committee

at each participating center before the study began. Written informed consent and participant

assent was obtained from each subject or caregiver as appropriate. An independent data

monitoring committee conducted safety reviews throughout the course of the trial.

Study Subjects

All eligible subjects were required to have a confirmed diagnosis of CF (23), defined as a

sweat chloride value greater than 60 mmol/L by quantitative pilocarpine iontophoresis or 2 CF-

causing mutations, and chronic sinopulmonary disease or gastrointestinal/nutritional

abnormalities; a forced expiratory volume in 1 second (FEV1) of 40-90% of the predicted value

for persons of their age, sex, race, and height (24); and a body weight of at least 40 kg and

body mass index of at least 18.5 kg/m2.

Eligible subjects in the dose escalation and alternate dosage regimen testing phases

were at least 18 years of age and homozygous for F508del. Eligible heterozygous subjects

were at least 12 years of age, were compound heterozygous for F508del and G551D, and

must have been taking physician-prescribed ivacaftor for at least 28 days at the time of

screening. Confirmation of genotype results was required before enrollment.

All subjects were randomly assigned in a 4:1 ratio to receive active drug or matched

placebo for 28 days, with an additional 28-day follow-up. Subjects who prematurely

discontinued treatment were required to complete the safety follow-up visit approximately 28

days after administration of the last dose of study drug. During the course of the study,

subjects were required to remain on their routine, stable medication regimen. In the dose

escalation phase, subjects received increasing doses by cohort. Subjects received tezacaftor

10 mg, 30 mg, 100 mg, or 150 mg qday alone or in combination with ivacaftor 150 mg q12h. In

the alternate dosage regimen testing phase, subjects received tezacaftor 100 mg

qday/ivacaftor 50 mg q12h or tezacaftor 50 mg q12h/ivacaftor 150 mg q12h. Subjects who

were compound heterozygous for F508del and G551D received tezacaftor 100 mg qday in

combination with physician-prescribed ivacaftor 150 mg q12h. Placebo subjects in this group

continued on physician-prescribed ivacaftor throughout the study.

Endpoints

The primary endpoints were safety through day 56, as determined by adverse events, clinical

laboratory values, standard digital electrocardiograms (ECGs), and vital signs, and change in

sweat chloride from baseline through day 28. Secondary endpoints included absolute and

relative changes in percent predicted FEV1 (ppFEV1) from baseline through day 28,

pharmacokinetic (PK) parameters, and change in Cystic Fibrosis Questionnaire-Revised

(CFQ-R) respiratory domain score from baseline to each visit up to day 28. Endpoints were

assessed every 7 days during the treatment and washout periods.

Statistical Analyses

Since this was a proof-of-concept study, no formal sample size determination was conducted.

Safety and efficacy were evaluated in all subjects who received at least one dose of study

drug. Independent comparisons of efficacy (eg, ppFEV1) and other clinical parameters were

performed in subjects homozygous for F508del and in those compound heterozygous for

F508del/G551D. Comparisons were made both within and between treatment groups. Change

in sweat chloride or ppFEV1 from baseline through day 28 was analyzed via a mixed-model for

repeated measures (MMRM). The average treatment effect across all post-baseline visits

obtained from the MMRM was used as the effect estimate for within and between group

comparisons. No alpha level adjustment for multiple comparisons was performed. Statistical

significance was defined as P < 0.05 and is only reported for the combination treatment of the

two higher doses of tezacaftor (100 mg qday and 150 mg qday).

Placebo subjects were pooled for between group comparisons in the dose escalation

and alternate dosage regimen testing phases. Subjects who received tezacaftor 100 mg

qday/ivacaftor 150 mg q12h in the dose escalation phase were included in the analyses with

the alternate dosage regimens.

Results

Results for baseline demographics, subject disposition, and safety were pooled into

monotherapy and combination therapy groups. Detailed results for each study arm are

presented in the supplemental appendix.

Study Population

The study was conducted from February 2012 through March 2014 at 37 CF centers in the

United States, Canada, Germany, and the United Kingdom. The screening, randomization, and

follow-up of subjects are shown in Figures 2 and E1. Overall, 185 of 190 subjects (97.4%)

completed the study and follow-up; 94.2% of subjects completed the full dosage regimen, with

a mean compliance (calculated as the number of tablets consumed relative to the number of

tablets administered) of 97.9%.

Baseline characteristics were well balanced among all study arms in subjects

homozygous for F508del (Tables 1; E1). Overall, the mean age was 30 years (SD 8.0), 44%

were female, the mean sweat chloride concentration was 95 mmol/L (SD 18.7), and the mean

ppFEV1 was 61 (SD 14.1). Baseline mean sweat chloride for subjects compound heterozygous

for F508del/G551D was 52.9 mmol/L (SD 19.6) in the active drug arm and 56.7 mmol/L (SD

22.1) in the placebo arm, consistent with the effects of ivacaftor (15,18).

Safety

The incidence of adverse events through day 56 was similar across study arms. Five subjects

homozygous for F508del discontinued the study (1 due to an adverse event, 1 due to

noncompliance, 1 was lost to follow-up, and 2 for other reasons, which were unspecified). Four

discontinuations occurred during the dose escalation phase (1 subject receiving tezacaftor 10

mg qday monotherapy, 1 receiving 100 mg qday monotherapy, 1 receiving 10 mg qday

combination therapy, and 1 receiving 30 mg qday combination therapy) and 1 during the

dosage regimen testing phase (tezacaftor 100 mg qday/ivacaftor 50 mg q12h). No subjects in

the F508del/G551D genotype cohort discontinued the study.

Tables 2 and E2 summarize the overall adverse events, serious adverse events, and

discontinuations that occurred through day 56. A total of 152 (88.4%) of 172 subjects

homozygous for F508del had at least 1 adverse event, with an incidence of 30 (90.9%)

subjects in the tezacaftor monotherapy arm, 92 (86.8%) subjects in the tezacaftor/ivacaftor

arm, and 30 (90.9%) subjects in the placebo arm. The majority (81.4%) of adverse events

were mild to moderate in nature. The most common adverse events by subject (≥15% in any

treatment group) were infective pulmonary exacerbation of CF, cough, increased sputum,

nausea, diarrhea, headache, and fatigue. Adverse events occurring in ≥15% of subjects in any

active drug arm are shown in Tables 3 and E3. Four adverse events, including cough, nausea,

fatigue, and increased sputum were more common in the tezacaftor monotherapy arm

compared with combination therapy (Table 3). However, the number of patients in the pooled

monotherapy arms was low (n=30), and examination of adverse events by cohort does not

suggest a dose relationship or dose-related increased intolerability. Serious adverse events

were reported in 15 subjects homozygous for F508del; ten of 139 subjects were in an active

drug arm (7%), and 5 of 33 subjects were in a placebo arm (15%). Fourteen of the 15 serious

adverse events were pulmonary exacerbations. One subject compound heterozygous for

F508del/G551D who received tezacaftor reported a serious adverse event of arthritis that was

considered not related to the study drug by the investigator. No deaths occurred during the

study.

Adverse events that occurred during the 28-day washout period were collected and

reported separately in Tables E4 and E5. During the washout period, a total of 120 (69.8%) of

172 subjects homozygous for F508del had at least 1 adverse event, with an incidence of 20

(60.6%) subjects in the tezacaftor monotherapy arm, 76 (71.7%) subjects in the

tezacaftor/ivacaftor arm, and 24 (72.7%) subjects in the placebo arm. The most common

adverse events by subject (≥15% in any treatment group) were infective pulmonary

exacerbation of CF, cough, headache, and nausea.

There were no clinically significant trends for laboratory tests, ECG parameters, vital

signs, weight, and body mass index.

Pharmacokinetics

Table E6 summarizes the PK of tezacaftor in all subjects. In subjects homozygous for

F508del, tezacaftor was rapidly absorbed following oral administration and reached steady

state by approximately 2 weeks. In the monotherapy arms, exposures of tezacaftor increased

in an approximately dose-proportional manner. Exposures of tezacaftor and its metabolites,

M1 and M2, were similar following tezacaftor monotherapy and tezacaftor/ivacaftor

combination therapy. In the dosage regimen testing phase, steady state area under the curve

(AUC) estimates of tezacaftor were similar when dosed at 50 mg q12h or 100 mg qday. The

geometric least squares mean ratios interval for tezacaftor exposures with combination therapy

(tezacaftor 100 mg qday/ivacaftor 150 mg q12h) relative to tezacaftor 100 mg qday

monotherapy were 0.998 (90% confidence interval [CI], 0.768, 1.30) for AUC and 1.07 (90%

CI, 0.844, 1.36) for Cmax. The mean accumulation ratios of tezacaftor based on AUC0-24h (day

28/day 1) were also similar following qday dosing of tezacaftor monotherapy and tezacaftor

100 mg qday/ivacaftor 150 mg q12h.

Table E7 summarizes the PK of ivacaftor in all subjects treated in the combination

therapy groups. Exposures of ivacaftor and its metabolites, M1 and M6, were also unaffected

by the co-administration with increasing doses of tezacaftor and were consistent with

previously observed exposures (25).

Tezacaftor 100 mg qday/ivacaftor 150 mg q12h in subjects compound heterozygous for

F508del/G551D yielded steady state exposures of tezacaftor and ivacaftor that were similar to

subjects homozygous for F508del (Tables E6 and E7).

Efficacy in the Dose Escalation Phase in Subjects Homozygous for F508del

In subjects homozygous for F508del, treatment resulted in mean within-group decreases in

sweat chloride from baseline through day 28 with the 2 higher doses of tezacaftor

monotherapy (100 mg qday and 150 mg qday) and with tezacaftor doses of 10 mg qday, 30

mg qday, and 100 mg qday given in combination with ivacaftor 150 mg q12h (P < 0.05 for 100

mg qday; Figure 3). Sweat chloride changes with tezacaftor 100 mg qday/ivacaftor 150 mg

q12h were also significant when compared with placebo through day 28 (P < 0.05; Table E8).

A clear dose response pattern was not observed in monotherapy or combination therapy

treatment arms. However the size of the treatment arms, particularly in the monotherapy

groups, was small. In all treatment arms, sweat chloride returned to near pretreatment levels

28 days after stopping treatment.

Treatment resulted in within-group improvements from baseline in ppFEV1 (absolute)

through day 28 with tezacaftor 10 mg qday monotherapy, while no treatment effect was

observed at the 3 higher doses. With combination therapy, within-group improvements from

baseline in ppFEV1 (absolute) were observed with tezacaftor doses of 30 mg qday, 100 mg

qday, and 150 mg qday in combination with ivacaftor 150 mg q12h (P < 0.05 for 100 mg qday

and 150 mg qday; Figure 3), in a pattern that suggested a dose-response relationship. The

absolute increase in ppFEV1 observed at the 2 higher doses of tezacaftor/ivacaftor was also

significant when compared with placebo through day 28 (P < 0.05 for both; Table E8). The

analyses of relative change in ppFEV1 were consistent with those of absolute change in

ppFEV1 (Table E8). In all treatment arms, ppFEV1 returned to near pretreatment levels 28 days

after stopping treatment (Figure 4).

The largest improvement in ppFEV1 (absolute) was observed in the tezacaftor 100 mg

qday/ivacaftor 150 mg q12h combination therapy arm (within-group increase from baseline of

3.75 percentage points [Figure 3]; treatment effect vs placebo: 3.89 percentage points; 95%

CI: 0.94, 6.83; P < 0.05 [Table E8]). The proportion of subjects experiencing an increase in

ppFEV1 from baseline through day 28 in this treatment arm was larger than that observed in

the placebo arm (Figure 4).

Combination therapy of tezacaftor 100 mg or 150 mg with ivacaftor 150 mg q12h

resulted in within-group increases from baseline in CFQ-R respiratory domain score through

day 28 of 5.15 points (P = 0.093)) and 7.62 points (P = 0.011), respectively. No significant

within-group changes in CFQ-R respiratory domain were observed in any other treatment

groups. No significant changes were observed when compared with placebo for any

monotherapy or combination therapy groups.

Efficacy in the Dosage Regimen Testing Phase in Subjects Homozygous for F508del

Tezacaftor 100 mg qday in combination with ivacaftor 150 mg q12h was selected during the

dose escalation phase as the most effective dose. During the dosage regimen testing phase,

alternate regimens, including a twice daily tezacaftor regimen (tezacaftor 50 mg q12h/ivacaftor

150 mg q12h) and a low dose ivacaftor regimen (tezacaftor 100 mg qday/ivacaftor 50 mg

q12h) were compared with responses to tezacaftor 100 mg qday with ivacaftor 150 q12h

observed during the dose escalation phase. All 3 dosage regimens resulted in within-group

decreases in sweat chloride from baseline through day 28 (Figure 5). Tezacaftor 50 mg

q12h/ivacaftor 150 mg q12h also resulted in a reduction in sweat chloride compared with

placebo (Table E9). However, treatment with the twice daily regimen or the low dose of

ivacaftor arm did not result in improvements (either within group, or vs placebo) in ppFEV1

(Figure 5; Table E9). Similarly, no changes (either within group or vs placebo) in CFQ-R

respiratory domain score were observed with either alternate regimen.

Efficacy in Subjects Compound Heterozygous for F508del and G551D

Subjects who were compound heterozygous for F508del and G551D received tezacaftor 100

mg qday or matched placebo while continuing to receive physician-prescribed ivacaftor 150

mg q12h. While the within-group decrease in sweat chloride from baseline through day 28 was

not significant (Figure 6), treatment resulted in a statistically significant mean absolute

decrease compared with placebo (treatment effect, −17.20, P < 0.05; Table E10). Treatment

also resulted in statistically significant mean absolute and relative within-group increases in

ppFEV1 from baseline through day 28 (4.60 and 7.29 percentage points, respectively, P < 0.05

for both; Figure 6 and data not shown). The treatment effect vs placebo, however, was not

significant for either absolute or relative change in ppFEV1 (Table E10). Concentrations of

sweat chloride and ppFEV1 values returned to near pretreatment levels 28 days after stopping

treatment (day 56) (Figure E2). Individual absolute change in ppFEV1 responses indicate that

12 of 14 (86%) subjects receiving tezacaftor in combination with ivacaftor experienced

increases in ppFEV1 from baseline through day 28 (Figure E2).

Combination of tezacaftor 100 mg qday with ivacaftor 150 mg q12h showed a mean

within-group increase in the CFQ-R respiratory domain score of 3.79 points (P = 0.1679) from

baseline through day 28. The treatment effect vs placebo was 6.81 points (P = 0.2451).

Discussion

This study is the first clinical trial of oral tezacaftor treatment in combination with ivacaftor in

subjects with CF homozygous for F508del and compound heterozygous for F508del/G551D.

Our results demonstrate that tezacaftor monotherapy and in combination with ivacaftor is well

tolerated, with low rates of discontinuation and similar incidences of adverse events in the

placebo, tezacaftor monotherapy, and tezacaftor/ivacaftor combination groups.

The most common adverse events were pulmonary or infectious in nature, which is

consistent with common manifestations of CF. The majority of adverse events were mild to

moderate in severity. The incidence of serious adverse events was lower in the tezacaftor

monotherapy and tezacaftor/ivacaftor combination groups than the placebo group, due largely

to the numerically lower number of pulmonary exacerbations. No other clinically significant

differences in safety profile were observed across any of the treatment groups.

In subjects homozygous for F508del, within-group and between-group decreases in

sweat chloride from baseline through day 28 were observed in the higher-dose tezacaftor

monotherapy groups (100 mg and 150 mg qday) and in most tezacaftor/ivacaftor combination

therapy groups. Changes in sweat chloride following tezacaftor monotherapy or

tezacaftor/ivacaftor combination therapy were not clearly dose dependent, suggesting that

there may be a threshold response among subjects homozygous for F508del. For absolute

and relative change in ppFEV1, within-group or compared with placebo, statistically significant

improvements were observed with tezacaftor/ivacaftor at the higher doses of tezacaftor (100

mg qday and 150 mg qday). The increases observed in the monotherapy groups were variable

and not dose dependent. By contrast, the increases in ppFEV1 in the combination therapy

groups showed dose dependency. Following discontinuation of treatment, sweat chloride and

lung function values returned to near pretreatment levels (day 28 to day 56), providing further

evidence that the effects observed during active dosing were treatment related.

The greatest improvements in both sweat chloride and lung function were observed in

the tezacaftor 100 mg qday/ivacaftor 150 mg q12h group during the dose escalation phase. In

the dosage regimen testing phase, lung function improvements were smaller when using a

twice-daily dosage regimen of tezacaftor (50 mg q12h) with ivacaftor 150 mg q12h or

tezacaftor 100 mg qday with a reduced dose of ivacaftor (50 mg q12h).

Improvements in lung function in patients homozygous for F508del were generally

comparable to or numerically greater than those observed in patients treated with

lumacaftor/ivacaftor in the phase 3, 24-week TRAFFIC/TRANSPORT studies (26). Treatment

initiation with lumacaftor/ivacaftor is sometimes associated with respiratory events and acute

lung function decline (26-30), which can restrict the number of patients willing to start

treatment. The improved benefit-to-risk profile makes tezacaftor/ivacaftor a potential treatment

option for a greater proportion of patients homozygous for F508del.

In subjects compound heterozygous for F508del and G551D, a numerical mean within-

group decrease in sweat chloride from baseline through day 28 was observed in the group

receiving tezacaftor 100 mg qday. Statistically significant within-group improvements from

baseline through day 28 were also observed in the tezacaftor group for the absolute and

relative change in ppFEV1. It is important to note that these subjects had been receiving

physician-prescribed ivacaftor for at least 28 days prior to initiation of tezacaftor treatment and

continued taking ivacaftor through the treatment and follow-up period; likewise, placebo

subjects were also taking ivacaftor during the study period. Therefore the treatment effects

observed with the addition of tezacaftor in these heterozygous subjects are greater than the

effect observed from ivacaftor alone, suggesting the potential to further enhance the benefit of

ivacaftor monotherapy in those who are compound heterozygous for F508del and an ivacaftor-

responsive mutation.

Lumacaftor/ivacaftor combination therapy is the only approved CFTR modulator

treatment for patients with CF homozygous for the F508del mutation. The combination of a

CFTR corrector and potentiator was a milestone treatment approach for CF (13) but is not

approved for patients with the F508del mutation who carry gating or other ivacaftor-responsive

mutations on their second allele. Tezacaftor in combination with ivacaftor may provide an

enhanced benefit-to-risk profile that could benefit a broader population of patients with CF than

either ivacaftor or lumacaftor/ivacaftor combination therapy.

Overall, these clinical trial results support the continued development of tezacaftor 100

mg qday in combination with ivacaftor 150 mg q12h in patients with CF. Based on these

results, this dosage regimen was chosen for phase 3 development. At the time this study was

initiated, ivacaftor was only approved for patients with the G551D gating mutation, therefore

patients with other gating mutations were not enrolled. Phase 3 studies are currently underway

to continue to evaluate tezacaftor/ivacaftor combination therapy in subjects heterozygous for

F508del and a gating mutation that has been shown to be clinically responsive to ivacaftor

(NCT02412111), in subjects homozygous for F508del (NCT02347657), and in subjects

heterozygous for F508del and a second mutation resulting in residual function

(NCT02392234).

Acknowledgements

Additional data review was performed by Kristin Stephan, PhD, an employee of Vertex

Pharmaceuticals Incorporated. Medical writing and editorial support were provided by

Stephanie Vadasz, PhD, and Dena McWain of Ashfield Healthcare Communications, which

received funding from Vertex Pharmaceuticals Incorporated. This project was supported in part

by the National Institutes of Health through grant numbers UL1RR024153 and UL1TR000005

(University of Pittsburgh) and the UK National Institute for Health Research (NIHR) Respiratory

Disease Biomedical Research Unit at the Royal Brompton and Harefield NHS Foundation

Trust and Imperial College London. The views expressed in this publication are those of the

authors and not necessarily those of the National Health Service, NIHR, or the Department of

Health. The full list of investigators is provided in the online data supplement.

Disclosures

JC, JAL, LV, and LTW are employees of Vertex Pharmaceuticals Incorporated and may own

stock or stock options in that company. SHD has served as a consultant for AlgiPharma AS

and has received research funding from Vertex Pharmaceuticals Incorporated, Gilead

Sciences, Parion Sciences, N30 Pharmaceuticals, and Grifols. JMP has served on advisory

boards for Vertex Pharmaceuticals Incorporated. ET has received fees from Vertex

Pharmaceuticals Incorporated related to consultation, participation on advisory boards, and

speaking engagements and has served on advisory boards for Novartis and Proteostasis. JCD

has served on advisory boards for Novartis, Pharmaxis, Proteostasis, Pulmocide, and Vertex

Pharmaceuticals Incorporated, and has undertaken educational activities for Vertex

Pharmaceuticals Incorporated (the funder of the study), for which her institution, Imperial

College, has received payment. MG has served on advisory boards for Vertex

Pharmaceuticals Incorporated and PTC Therapeutics for which he has received payment.

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Table 1. Baseline Characteristics

Subjects Homozygous for F508del

Subjects Compound Heterozygous for F508del and

G551DPooled

Tezacaftor Monotherapy

Pooled Tezacaftor

Combination Pooled Placebo

Active Combination

Drug

Placebo(Ivacaftor

Monotherapy)

Tezacaftor Dose10 mg qday-150 mg qday

10 mg qday-150 mg qday or 50

mg q12h NA 100 mg qday 100 mg qday

Ivacaftor Dose NA150 mg qday or

50 mg q12h NA 150 mg q12h NAN 33 106 33 14 4

Female, n (%) 14 (42.4) 47 (44.3) 13 (39.4) 6 (42.9) 3 (75.0)

Age, mean, y (SD) 30.8 (7.9) 29.5 (8.0) 30.7 (8.4) 26.6 (7.0) 34.5 (7.6)

BMI, mean, kg/m2 (SD) 22.4 (3.1) 22.5 (2.8) 21.8 (3.0) 24.6 (3.9) 22.9 (1.0)Sweat chloride, mean, mmol/L (SD) 101.8 (9.2) 99.0 (12.6) 98.4 (13.7) 52.9 (19.6) 56.7 (22.1)

FEV1, % predicted

Mean (SD) 61.1 (14.0) 61.5 (13.8) 58.0 (14.5) 59.1 (16.6) 62.6 (12.7)Range 35.6-89.0 34.2-90.7 35.2-89.9 31.1-79.4 52.6-80.9BMI=body mass index; FEV1=forced expiratory volume in 1 second; NA=not applicable; SD=standard deviation.

25

Table 2. Adverse Events in Subjects Homozygous for F508del Pooled Tezacaftor

MonotherapyPooled Tezacaftor

Combination Pooled PlaceboN 33 106 33Any AE, n (%) 30 (90.9) 92 (86.8) 30 (90.9)Any serious AE, n (%) 2 (6.1) 8 (7.5) 5 (15.2)Serious pulmonary exacerbation 2 (6.1) 7 (6.6) 5 (15.2)Discontinuation due to AE 1 (3.0) 4 (3.8) 0AE=adverse event.

Table 3. Adverse Events in Subjects Homozygous for F508del Occurring in ≥15% of Subjects in Any Active Drug Arm

Pooled Tezacaftor Monotherapy

Pooled Tezacaftor Combination

Pooled Placebo

N 33 106 33Adverse Event, n (%)Infective pulmonary exacerbation of CF 4 (12.1) 24 (22.6) 9 (27.3)Cough 10 (30.3) 17 (16.0) 6 (18.2)Headache 4 (12.1) 16 (15.1) 8 (24.2)Increased sputum 7 (21.2) 11 (10.4) 2 (6.1)Fatigue 7 (21.2) 7 (6.6) 3 (9.1)Nausea 8 (24.2) 11 (10.4) 1 (3.0)Diarrhea 5 (15.2) 6 (5.7) 2 (6.1)CF=cystic fibrosis.

FIGURE LEGENDS

Figure 1. Study Design aStudy arm analyzed in both the dose escalation and dosage regimen testing phases; bFive subjects counted in both pooled placebo groups.

Figure 2. Subject DispositionDisposition in subjects homozygous for F508del-pooled groups in the dose escalation phase (A), the alternate dosage regimen testing phase (B), and in subjects compound heterozygous for F508del and G551D (C). Figure E1 (available online) provides more detail on each study arm.aFive subjects were counted in both pooled placebo groups; bSeventeen subjects who received tezacaftor 100 mg qday/ivacaftor 150 mg q12h were counted in both the dose escalation and dosage regimen testing phases.

Figure 3. Efficacy in Subjects Homozygous for F508del in the Dose Escalation PhaseChange in sweat chloride (A) and absolute change in ppFEV1 (B) from baseline through day 28. Subjects in the combination therapy arms were treated with ivacaftor 150 mg q12h. Monotherapy arms are represented by solid bars. Combination therapy arms are presented by hatched bars. *P < 0.05 vs baseline within group; †P < 0.05 vs placebo; P values only reported for tezacaftor 100 mg qday and tezacaftor 150 mg qday/ivacaftor 150 mg q12h. CI=confidence interval; LS=least squares; ppFEV1=percent predicted forced expiratory volume in 1 second.

Figure 4. Efficacy in Combination Treatment in Subjects Homozygous for F508del in During the Dose Escalation PhaseMean absolute changes in ppFEV1 for the treatment and washout periods for tezacaftor + ivacaftor 150 mg q12h in the dose escalation phase (A) and individual subject absolute changes in ppFEV1 at day 28 for the tezacaftor 100 mg qday + ivacaftor 150 mg q12h (B) and placebo (C) cohorts. Analysis of change from baseline at all measurements up to day 28 was based on a mixed-effect model for repeated measures. For the washout period, summary statistics are shown. LS=least squares; ppFEV1=percent predicted forced expiratory volume in 1 second.

Figure 5. Efficacy in Subjects Homozygous for F508del in the Dosage Regimen Testing Phase Change in sweat chloride (A) and absolute change in ppFEV1 (B) from baseline through day 28. aSubjects also analyzed in the dose escalation phase; bComparison vs placebo not calculated.*P < 0.05 vs baseline within group; †P < 0.05 vs placebo through day 28; P values only reported for tezacaftor 100 mg qday and tezacaftor 150 mg qday/ivacaftor 150 mg q12h. CI=confidence interval; LS=least squares; ppFEV1=percent predicted forced expiratory volume in 1 second.

Figure 6. Efficacy in Subjects Compound Heterozygous for F508del and G551D Who Received Combination TherapyChange in sweat chloride (A) and absolute change in ppFEV1 (B) from baseline through day 28.*P < 0.05 vs baseline within group; †P < 0.05 vs placebo through day 28. CI=confidence interval; LS=least squares; ppFEV1=percent predicted forced expiratory volume in 1 second.

Tezacaftor/Ivacaftor in Subjects with Cystic Fibrosis and F508del/F508del-CFTR or F508del/G551D-CFTR

Scott Donaldson, Joseph M. Pilewski, Matthias Griese, Jon Cooke, Lakshmi Viswanathan, Elizabeth Tullis, Jane C. Davies, Julie A. Lekstrom-Himes, Linda T. Wang

Online Data Supplement

List of InvestigatorsThe VX-661-101 Study Group included: Steven Rowe, University of Alabama at Birmingham; John Clancy, Cincinnati Children’s Hospital Medical Center; Karen McCoy, Nationwide Children’s Hospital; Moira Aitken, University of Washington; Scott Donaldson, University of North Carolina School of Medicine; Joseph Pilewski, University of Pittsburgh; Theodore Liou, University of Utah; Philip Black, Children’s Mercy Hospital; Rubin Cohen, Hofstra University; Robert Vender, Pennsylvania State University; Allen Lapey, Massachusetts General Hospital; Manu Jain, Northwestern University Feinberg School of Medicine; Susan Millard, Helen DeVos Children’s Hospital CF Care Center; Gregory Shay, Kaiser Permanente; Henry Thompson, St. Luke’s CF Clinic; Robert Zanni, Monmouth Medical Center; Patrick Flume, Medical University of South Carolina; James Royall, University of Oklahoma Health Sciences Center; Laurie LeClair, University of Vermont College of Medicine; Elizabeth Tullis, St. Michael’s Hospital; Pearce Wilcox, Pacific Lung Research Centre; Roger Michael, Queen Elizabeth II Health Sciences Center; Harvey Rabin, University of Calgary; Yves Berthiaume, University of Montreal Hospital Research Centre; Burkhard Tuemmler, Hannover Medical School; Matthias Griese, Ludwig-Maximilians University; Jochen Mainz, Jena University Hospital; Theodor Zimmerman, University of Erlangen; Silke Van Koningsbruggen-Rietschel, University Hospital of Cologne; Manfred Ballmann, St. Josef-Hospital; Nico Derichs, Charite University Medicine Berlin; Wolfgang Gleiber, J.W. Goethe-University Hospital; Charles Haworth, Papworth Hospital; Ian Ketchell, University Hospital Llandough; Mary Carrol, Southampton General Hospital; Alex Horsley, University of Manchester.

Table E1. Baseline Characteristics Subjects Homozygous for F508del Subjects Compound

Heterozygous for F508del/G551DDose Escalation

Dosage Regimen Testing

Monotherapy Combination

Pooled Placeb

oa Active Drugb

Pooled Placeb

oa

ActiveCombination

Drug

Placebo(Ivacaftor

Monotherapy)

Tezacaftor Dose10 mg qday

30 mg qday

100 mg qday

150 mg qday

10 mg qday

30 mg qday

100 mg qdayb

150 mg qday NA

100 mg qday

50 mg q12h NA

100 mg qday NA

Ivacaftor Dose NA 150 mg q12h NA50 mg q12h

150 mg q12h NA 150 mg q12h NA

N 8 8 8 9 18 19 17 17 24 19 16 14 14 4Female, n

(%)4

(50.0)4

(50.0)3

(37.5)3

(33.3)6

(33.3)6

(31.6)11

(64.7)10

(58.8)8

(33.3)7

(36.8)7

(43.8)6

(42.9)6

(42.9)3

(75.0)

Age, mean, y (SD)

35.3(8.3)

30.8(6.6)

29.1(7.1)

28.2(8.6)

28.3(7.1)

29.2(6.4)

31.0(9.3)

28.2(6.5)

30.2(7.8)

27.9(5.6)

32.8(11.9)

31.4(9.1)

26.6(7.0)

34.5(7.6)

BMI, mean, kg/m2 (SD)

22.7(4.2)

23.6(3.6)

21.4(2.0)

22.2(2.3)

23.0(3.5)

22.3(2.6)

23.0(3.7)

22.0(2.3)

21.7(2.4)

21.9(2.5)

23.1(2.1)

22.2(4.0)

24.6(3.9)

22.9(1.0)

Sweat chloride, mean, mmol/L

(SD)

98.3(6.8)

102.7(8.8)

102.2(11.9)

103.7(9.3)

107.1(8.0)

102.3(10.5)

103.3(6.0)

101.2(6.3)

102.3(8.2)

79.2(9.5)

102.7(9.6)

92.5(16.9)

52.9(19.6)

56.7(22.1)

FEV1, % predicted

Mean (SD)

64.3(11.6)

61.4(19.2)

62.5(13.1)

56.9(12.8)

61.8(13.0)

62.0(13.6)

58.7(16.0)

59.8(16.0)

57.8(15.3)

62.6(14.6)

64.0(10.2)

58.7(14.8)

59.1(16.6)

62.6(12.7)

Range 50.0-80.4

35.6-89.0

43.8-86.5

37.8-77.1

42.1-86.7

40.6-87.5

36.4-90.5

34.2-90.7

35.2-89.9

39.3-84.5

44.3-77.1

39.9-84.3

31.1-79.4

52.6-80.9

aFive subjects counted in both pooled placebo groups; bSeventeen subjects counted in both the dose escalation and dosage regimen testing groups.BMI=body mass index;FEV1=forced expiratory volume in 1 second; NA=not applicable; SD, standard deviation.

Table E2. Summary of Adverse Events  Subjects Homozygous for F508del Subjects Compound

Heterozygous for F508del/G551DDose Escalation

Dosage Regimen Testing

Pooled PlaceboMonotherapy Combination Active Druga

Active Combination

Drug

Placebo (Ivacaftor

Monotherapy)

Tezacaftor Dose10 mgqday

30 mgqday

100 mgqday

150 mgqday

10 mgqday

30 mg qday

100 mgqdaya

150 mgqday

100 mg qday

50 mg q12h NA

100 mgqday NA

Ivacaftor Dose NA150 mgq12h

50 mg q12h

150 mg q12h NA 150 mg q12h NA

N 8 8 8 9 18 19 17 17 19 16 33 14 4Any AE, n

(%)8

(100)7

(87.5)7

(87.5)8

(88.9)15

(83.3)18

(94.7)10

(58.8)17

(100)16

(84.2)16

(100)30

(90.9)12

(85.7)2

(50.0)

Any serious AE, n(%)

1(12.5)

1(12.5)

0 (0)

0(0)

1(5.6)

2(10.5)

2(11.8)

0(0)

1(5.3)

2(12.5)

5(15.2)

1(7.1)

0(0)

Serious pulmonary exacerbation, n

(%)

1(12.5)

1(12.5)

0(0)

0(0)

1(5.6)

1(5.3)

2(11.8)

0(0)

1(5.3)

2(12.5)

5(15.2)

0(0)

0(0)

Discontinuation due to AE, n

(%)

1(12.5)

0(0)

0(0)

0(0)

1(5.6)

0(0)

2(11.8)

1(5.9)

0(0)

0(0)

0(0)

0(0)

0(0)

aSeventeen subjects counted in both the dose escalation and dosage regimen testing groups.AE=adverse event.

Table E3. Adverse Events Occurring in ≥15% of Subjects in Any Active Drug Arm Subjects Homozygous for F508del Subjects Compound

Heterozygous for F508del/G551D

 Dose Escalation

Dosage Regimen Testinga

Pooled PlaceboMonotherapy Combination

Active Combination

Drug

Placebo (Ivacaftor

Monotherapy)

Tezacaftor Dose10 mgqday

30 mgqday

100 mgqday

150 mgqday

10 mgqday

30 mgqday

100 mgqdaya

150 mgqday

100 mg qday

50 mg q12h NA

100 mgqday NA

Ivacaftor Dose NA150 mg

q12h50 mg q12h

150 mg q12h NA

150 mg q12h NA

N 8 8 8 9 18 19 17 17 19 16 33 14 4Adverse Event, n (%)Infective pulmonary exacerbation of CF 1 (12.5) 1 (12.5) 1 (12.5) 1 (11.1) 5 (27.8) 5 (26.3) 4 (23.5) 2 (11.8) 3 (15.8) 5 (31.3) 9 (27.3) 3 (21.4) 1 (25.0)

Cough 3 (37.5) 3 (37.5) 2 (25.0) 2 (22.2) 2 (11.1) 3 (15.8) 2 (11.8) 3 (17.6) 4 (21.1) 3 (18.8) 6 (18.2) 4 (28.6) 0 (0)

Headache 1 (12.5) 1 (12.5) 1 (12.5) 1 (11.1) 2 (11.1) 4 (21.1) 0 (0) 2 (11.8) 4 (21.1) 4 (25.0) 8 (24.2) 3 (21.4) 0 (0)

Increased sputum 2 (25.0) 2 (25.0) 1 (12.5) 2 (22.2) 2 (11.1) 1 (5.3) 2 (11.8) 1 (5.9) 2 (10.5) 3 (18.8) 2 (6.1) 0 (0) 0 (0)

Fatigue 4 (50.0) 1 (12.5) 1 (12.5) 1 (11.1) 1 (5.6) 3 (15.8) 0 (0) 2 (11.8) 0 (0) 1 (6.3) 3 (9.1) 1 (7.1) 0 (0)

Nausea 1 (12.5) 2 (25.0) 1 (12.5) 4 (44.4) 2 (11.1) 2 (10.5) 1 (5.9) 0 (0) 1 (5.3) 5 (31.3) 1 (3.0) 2 (14.3) 0 (0)

Diarrhea 2 (25.0) 1 (12.5) 1 (12.5) 1 (11.1) 2 (11.1) 1 (5.3) 0 (0) 1 (5.9) 0 (0) 2 (12.5) 2 (6.1) 0 (0) 0 (0)

Hemoptysis 2 (25.0) 0 (0) 2 (25.0) 0 (0) 0 (0) 2 (10.5) 1 (5.9) 1 (5.9) 0 (0) 1 (6.3) 2 (6.1) 1 (7.1) 0 (0)

Vomiting 0 (0) 1 (12.5) 1 (12.5) 2 (22.2) 1 (5.6) 2 (10.5) 0 (0) 1 (5.9) 0 (0) 1 (6.3) 1 (3.0) 1 (7.1) 0 (0)

Pyrexia 3 (37.5) 0 (0) 0 (0) 1 (11.1) 0 (0) 1 (5.3) 0 (0) 1 (5.9) 1 (5.3) 0 (0) 2 (6.1) 2 (14.3) 0 (0)

Rales 2 (25.0) 0 (0) 0 (0) 0 (0) 2 (11.1) 1 (5.3) 2 (11.8) 1 (5.9) 0 (0) 0 (0) 0 (0) 1 (7.1) 1 (25.0)

Nasopharyngitis 0 (0) 1 (12.5) 0 (0) 0 (0) 1 (5.6) 2 (10.5) 0 (0) 3 (17.6) 0 (0) 3 (18.8) 1 (3.0) 1 (7.1) 1 (25.0)Musculoskeletal chest pain 0 (0) 0 (0) 2 (25.0) 0 (0) 1 (5.6) 0 (0) 0 (0) 1 (5.9) 0 (0) 0 (0) 2 (6.1) 0 (0) 0 (0)

Nasal congestion 2 (25.0) 0 (0) 1 (12.5) 1 (11.1) 0 (0) 0 (0) 0 (0) 1 (5.9) 2 (10.5) 1 (6.3) 1 (3.0) 1 (7.1) 1 (25.0)

Sinusitis 2 (25.0) 0 (0) 0 (0) 0 (0) 1 (5.6) 0 (0) 0 (0) 1 (5.9) 0 (0) 0 (0) 3 (9.1) 1 (7.1) 0 (0)

Dizziness 0 (0) 3 (37.5) 0 (0) 1 (11.1) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 1 (6.3) 0 (0) 0 (0) 0 (0)

Gastroenteritis 2 (25.0) 0 (0) 0 (0) 1 (11.1) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0)

Flatulence 0 (0) 2 (25.0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 1 (6.3) 0 (0) 0 (0) 0 (0)

Abdominal pain 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) 1 (5.3) 0 (0) 0 (0) 3 (15.8) 1 (6.3) 2 (6.1) 0 (0) 0 (0)aSeventeen subjects counted in both the dose escalation and dosage regimen testing groups.

CF=cystic fibrosis; NA=not applicable.

Table E4. Adverse Events in Subjects Homozygous for F508del Occurring in ≥15% of Subjects in Any Active Drug Arm During the 28-Day Washout

Pooled Tezacaftor Monotherapy

Pooled Tezacaftor Combination Pooled Placebo

N 33 106 33AE, n (%)Any AE 20 (60.6) 76 (71.7) 24 (72.7)

Infective pulmonary exacerbation of CF 1 (3.0) 21 (19.8) 5 (15.2)

Cough 5 (15.2) 8 (7.5) 3 (9.1)Headache 3 (18.8) 0 (0) 1 (3.0)Nausea 5 (15.2) 6 (5.7) 0 (0)

AE=adverse event; CF=cystic fibrosis.

Table E5. Adverse Events Occurring in ≥15% of Subjects in Any Active Drug Arm During the 28-Day WashoutSubjects Homozygous for F508del Subjects Compound

Heterozygous for F508del/G551D

 Dose Escalation

Dosage Regimen Testinga

Pooled PlaceboMonotherapy Combination

Active Combination

Drug

Placebo (Ivacaftor

Monotherapy)

Tezacaftor Dose10 mgqday

30 mgqday

100 mgqday

150 mgqday

10 mgqday

30 mgqday

100 mgqdaya

150 mgqday

100 mg qday

50 mg q12h NA

100 mgqday NA

Ivacaftor Dose NA150 mg

q12h50 mg q12h

150 mg q12h NA

150 mg q12h NA

N 8 8 8 9 18 19 17 17 19 16 33 14 4AE, n (%)

Any AE 7 (87.5) 4 (50.0) 2 (25) 7 (77.8) 13 (72.2) 14 (73.7) 9 (52.9) 15 (88.2) 13 (68.4) 12 (75.0) 24

(72.7) 7 (50.0) 2 (50.0)

Infective pulmonary exacerbation of CF

0 (0) 0 (0) 0 (0) 1 (11.1) 5 (27.8) 5 (26.3) 4 (23.5) 2 (11.8) 2 (10.5) 3 (18.8) 5 (15.2) 2 (14.3) 1 (25.0)

Cough 1 (12.5) 2 (25.0) 0 (0) 2 (22.2) 1 (5.6) 0 (0) 1 (5.9) 1 (5.9) 3 (15.8) 2 (12.5) 3 (9.1) 2 (14.3) 0 (0)

Headache 0 (0) 0 (0) 0 (0) 0 (0) 1 (5.6) 1 (5.3) 0 (0) 0 (0) 0 (0) 3 (18.8) 1 (3.0) 1 (7.1) 0 (0)

Nausea 1 (12.5) 1 (12.5) 0 (0) 3 (33.3) 1 (5.6) 1 (5.3) 0 (0) 0 (0) 1 (5.3) 3 (18.8) 0 (0) 1 (7.1) 0 (0)

Diarrhea 2 (25.0) 0 (0) 0 (0) 1 (11.1) 1 (5.6) 1 (5.3) 0 (0) 1 (5.9) 0 1 (6.3) 1 (3.0) 0 (0) 0 (0)

Pyrexia 3 (37.5) 0 (0) 0 (0) 0 (0) 1 (5.6) 1 (5.3) 0 (0) 0 (0) 0 (0) 0 (0) 1 (3.0) 1 (7.1) 0 (0)aSeventeen subjects counted in both the dose escalation and dosage regimen testing groups.AE=adverse event; CF=cystic fibrosis; NA=not applicable.

Table E6. Pharmacokinetic Parameters of TezacaftorSubjects Homozygous for F508del Subjects Compound

Heterozygous for F508del/G551D

 Dose Escalation

Dosage Regimen TestingaMonotherapy Combination

Active Combination Drug

Tezacaftor Dose10 mgqday

30 mgqday

100 mgqday

150 mgqday

10 mgqday

30 mgqday

100 mgqdaya

150 mgqday

100 mg qday

50 mg q12h

100 mgqday

Ivacaftor Dose NA150 mgq12h

50 mg q12h

150 mg q12h

150 mg q12h

Day 1N 8 8 8b 9 18c 16 15d 16 18e 16f 13g

tmax, median (range), h

3.86 (2.08-4.02)

2.50 (0.50-6.02)

3.52 (2.00-4.08)

2.98 (1.00-4.02)

3.00 (0.95-23.90)

2.06 (1.00-6.00)

3.30 (0.98-6.25)

2.47 (0.97-6.00)

3.40 (2.00-11.10)

2.59 (1.00-11.00)

3.07 (1.00-9.08)

Cmax, mean (CV%), ng*h/mL

479 (29)

1490 (43)

5530 (24)

7120 (24)

524 (30)

1360 (22)

5260 (29)

8200 (29)

4720 (20)

2270 (33)

5120 (23)

AUC0-24h, mean (CV%), ng*h/mL

4450 (28)

13200 (21)

57400 (38)

75000 (21)

4880 (23)

13000 (20)

51900 (30)

83900 (29)

49800 (16)

31400 (23)

57200 (20)

Day 28N 7h 8 8i 9 17j 13k 15l 16m 17n 16o 14p

tmax, median (range), h

3.18 (0.97-6.22)

2.48 (0.97-3.83)

4.08 (2.00-1.40)

3.98 (1.95-6.00)

2.02 (0.87-8.08)

2.05 (1.00-4.13)

4.00 (1.00-9.28)

2.97 (2.00-5.85)

2.85 (1.00-9.00)

3.45 (0.97-9.00)

3.28 (1.92-8.72)

Cmax, mean (CV%), ng*h/mL

563 (29)

1930 (26)

6250 (42)

7790 (13)

751 (24)

2240 (21)

6520 (28)

10200 (28)

6270 (25)

4300 (27)

6670 (30)

AUC0-24h, mean (CV%), ng*h/mL

6260 (42)

23000 (28)

88100 (58)

98900 (20)

8950 (27)

26300 (22)

82700 (28)

138000 (36)

77600 (23)

73300 (31)

90600 (34)

CLss/F, mean (CV%), L/h

1.84 (41)

1.43 (37)

1.34 (33)

1.58 (21)

1.20 (28)

1.19 (22)

1.31 (31)

1.25 (43)

1.37 (31)

1.46 (24)

1.26 (43)

t1/2, mean (CV%), h89.9 (43)

173 (26)

111 (26)

166 (26)

105 (64)

136 (31)

156 (34)

147 (24)

149 (38)

158 (37)

170 (29)

ARAUC0-24h,q mean (CV%), ng*h/mL

1.39 (15)

1.76 (22)

1.54 (23)

1.34 (16)

1.94 (20)

1.88 (23)

1.59 (20)

1.69 (23)

1.55 (16)

2.23 (20)

1.67 (31)

aSeventeen subjects counted in both the dose escalation and dosage regimen testing groups; bN=7 for AUC0-24h; cN=17 for AUC0-24h; dN=12 for AUC0-24h; eN=17 for AUC0-24h; fN=13 for AUC0-24h; gN=10 for AUC0-24h; hN= 6 for t1/2; iN=7 for t1/2 and ARAUC0-24h; jN=16 for AUC0-24h; kN=12 for t1/2 and N=10 for AUC0-24h; lN=14 for t1/2 and N=12 for ARAUC0-24h; mN=15 for ARAUC0-24h; nN=15 for ARAUC0-24h; oN=15 for AUC0-24h and CLssF/N; N=14 for t1/2; N=12 for ARAUC0-24h; pN=10 for ARAUC0-24h; qARAUC0-24h was calculated as day 28 tezacaftor AUC0-24h/day 1 tezacaftor AUC0-24h.AR=accumulation ratio; AUC=area under the concentration versus time curve; CLss/F=total systemic clearance; Cmax=maximum concentration; CV=coefficient of variation; NR=not reported; tmax=time of maximum concentration.

Table E7. Pharmacokinetic Parameters of IvacaftorSubjects Homozygous for F508del Subjects Compound

Heterozygous for F508del/G551Da

 Dose Escalation

Dosage Regimen Testinga

Tezacaftor Dose10 mgqday

30 mgqday

100 mgqdayb

150 mgqday

100 mg qday

50 mg q12h

100 mgqday

Ivacaftor Dose150 mgq12h

50 mg q12h

150 mg q12h

150 mg q12h

Day 1N 18c 18c 17d 13e 19e 16f 13g

tmax, median (range), h

3.96(2.05-5.98)

4.00(2.98-9.17)

4.05(3.00-11.20)

4.00(1.83-12.00)

4.08(1.93-12.00)

5.08(2.00-11.03)

3.97(1.98-6.00)

Cmax, mean (CV%), ng*h/mL

660 (35)

681 (43)

699 (44)

872 (47)

207 (47)

687 (46)

1150 (46)

AUC0-12h, mean (CV%), ng*h/mL

4590 (38)

5370 (39)

4720 (32)

6530 (48)

1570 (34)

4450 (31)

8850 (37)

Day 28N 17h 11i 14j 13k 16l 15m 14tmax, median (range), h

3.17 (0.48-11.02)

4.13 (200-11.00)

4.00 (3.00-6.08)

4.02 (2.98-6.02)

4.01 (2.00-9.12)

3.77 (1.88-6.00)

4.04 (2.03-8.72)

Cmax, mean (CV%), ng*h/mL

1130 (37)

1280 (40)

1280 (35)

1720 (61)

395 (47)

1410 (42)

1350 (47)

AUC0-12h, mean (CV%), ng*h/mL

10100 (43%)

11800(42%)

10900 (36)

16000 (65)

3690 (40)

11800 (46)

12400 (50)

CLss/F, mean (CV%), L/h

17.1 (35)

15.3 (50)

15.7 (41)

14.0 (86)

16.1 (47)

14.9 (35)

16.7 (68)

t1/2, mean (CV%), h21.4 (62)

11.6 (42)

16.0 (152)

10.3 (24)

10.9 (39)

11.4 (60) NR

ARAUC0-12h,n mean (CV%), ng*h/mL

2.71 (84)

2.14 (47)

2.58 (29)

2.32 (32)

2.46 (46)

1.87 (30) NA

aIvacaftor levels were steady state on day 1; bSeventeen subjects counted in both the dose escalation and dosage regimen testing groups; cN=14 for AUC0-12h; dN=12 for AUC0-12h; eN=11 for AUC0-12h; fN=9 for AUC0-12h; gN=8 for AUC0-12h; hN=16 for AUC0-12h and CLss/F; N=15 for t1/2; N=12 for ARAUC0-12h; iN=9 for t1/2 and ARAUC0-12h; jN=13 for AUC0-12h, CLss/F, and t1/2; N=10 for ARAUC0-12h; kN=11 for ARAUC0-12h; lN=15 for AUC0-12h CLss/F; N=12 for t1/2; N=8 for ARAUC0-12h; mN=14 for AUC0-12h, CLss/F, and t1/2; N=7 for ARAUC0-12h; nARAUC0-12h was calculated as day 28 ivacaftor AUC0-12/day 1 ivacaftor AUC0-12h.AR=accumulation ratio; AUC0-24h=area under the concentration versus time curve; CLss/F=total systemic clearance; Cmax=maximum concentration; CV=coefficient of variation; NA=not applicable; NR=not reported; tmax=time of maximum concentration.

Table E8. Treatment Effects Compared with Placebo in the Dose Escalation Phase in Subjects Homozygous for F508del

Monotherapy CombinationPooled Placebo

Tezacaftor Dose

10 mg qday

30 mg qday

100 mg qday

150 mg qday

10 mg qday

30 mg qday

100 mg qday

150 mg qday NA

Ivacaftor Dose NA 150 mg q12h NAAbsolute change in sweat chloride from baseline through day 28a (mmol/L)Nb 8 6 8 9 18 18 17 17 24Treatment effectc

4.77 −3.91 −19.58 −9.60 −4.20 −5.14 −5.19 −1.77 NA

95% CI −0.30, 9.84 −9.50, 1.68 −24.57, −14.59

−14.38, −4.82

−8.10, −0.31

−9.03, −1.25

−9.16, −1.21

−5.71, 2.17 --

P value NR NR NR NR NR NR 0.0110* 0.3745 --

Absolute change in ppFEV1 from baseline through day 28a (percentage points)N 8 8 8 9 18 19 17 17 24Treatment effectc

3.63 1.76 1.74 2.68 1.44 3.03 3.89 3.75 NA

95% CI −0.16, 7.42 −1.99, 5.52 −2.01, 5.50 −0.92, 6.27 −1.43, 4.31 0.19, 5.88 0.94, 6.83 0.82, 6.68 --P value NR NR NR NR NR NR 0.0101* 0.0125* --

Relative change in ppFEV1 from baseline through day 28a (percentage points)N 8 8 8 9 18 19 17 17 24Treatment effectc

4.87 2.32 2.78 4.15 2.61 4.73 7.04 6.47 NA

95% CI −1.91, 11.65 −4.40, 9.03 −3.94, 9.50 −2.28, 10.59 −2.53, 7.75 −0.37, 9.82 1.77, 12.31 1.23,

11.71 --

P value NR NR NR NR NR NR 0.0093* 0.0160* --aObtained from mixed-effect model for repeated measures (MMRM) with dependent variable absolute change from baseline, fixed effects for treatment, categorical visit (day 7, day 14, day 21, and day 28), and treatment by visit interaction, with adjustment for continuous baseline values, using a compound symmetry covariance matrix;. bThree subjects did not have post-baseline sweat chloride assessments; cDifference between treatments for the least squares mean change from baseline and P value for between treatment comparison. *P < 0.05 vs placebo through day 28; P values only reported for tezacaftor 100 mg qday and tezacaftor 150 mg qday/ivacaftor 150 mg q12h.CI=confidence interval; LS=least squares; NA=not applicable; NR=not reported; ppFEV1=percent predicted forced expiratory volume in 1 second.

Table E9. Treatment Effects Compared with Placebo in the Dosage Regimen Testing Phase

Active Combination Drug Pooled PlaceboTezacaftor Dose 50 mg q12h 100 mg qday NAIvacaftor Dose 150 mg q12h 50 mg qday NAAbsolute change in sweat chloride from baseline through day 28a (mmol/L)Nb 16 18 14Treatment effectc −6.70 −4.89 NA95% CI −12.94, −0.46 −11.20, 1.42 --

Absolute change in ppFEV1 from baseline through day 28a (percentage points)Nc 16 18 14Treatment effectc 0.84 −0.53 NA95% CI −2.82, 4.51 −4.10, 3.04 --

Relative change in ppFEV1 from baseline through day 28a (percentage points)Nc 16 18 14Treatment effectc 1.02 −1.57 NA95% CI −6.04, 8.08 −8.44, 5.30 --

aObtained from mixed-effect model for repeated measures (MMRM) with dependent variable absolute change from baseline, fixed effects for treatment, categorical visit (day 7, day 14, day 21, and day 28), and treatment by visit interaction, with adjustment for continuous baseline values, using a compound symmetry covariance matrix; bOne subject did not have post-baseline assessments; cDifference between treatments for the least squares mean change from baseline and P value for between treatment comparison. CI=confidence interval; LS=least squares; NA=not applicable; ppFEV1=percent predicted forced expiratory volume in 1 second.

Tezacaftor 100 mg qday/Ivacaftor 150 mg q12h

Placebo/Ivacaftor 150 mg q12h

Absolute change in sweat chloride from baseline through day 28a (mmol/L)Nb 13 4Treatment effectc −17.20 NA95% CI −31.75, −2.65 --P value 0.0238* --

Absolute change in ppFEV1 from baseline through day 28a (percentage points)N 14 4Treatment effectc 3.20 NA95% CI −4.10, 10.51 --P value 0.3646 --Relative change in ppFEV1 from baseline through day 28a (percentage points)N 14 4Treatment effectc 3.72 NA95% CI −7.77, 15.21 --P value 0.5007 --Table E10. Treatment Effects Compared with Placebo in Subjects Compound Heterozygous for F508del and G551D Who Were Receiving Physician-Prescribed IvacaftoraObtained from mixed-effect model for repeated measures (MMRM) with dependent variable absolute change from baseline, fixed effects for treatment, categorical visit (day 7, day 14, day 21, and day 28), and treatment by visit interaction, with adjustment for continuous baseline values, using a compound symmetry covariance matrix; bOne subject did not have post-baseline sweat chloride assessments; cDifference between treatments for the least squares mean change from baseline and P value for between treatment comparison.*P < 0.05 vs placebo through day 28.CI=confidence interval; LS=least squares; NA=not applicable; ppFEV1=percent predicted forced expiratory volume in 1 second.

Figure E1. Subject Disposition Disposition for all subjects in the dose escalation phase (A), the dosage regimen testing phase (B), and in subjects compound heterozygous for F508del and G551D (C).aFive subjects were counted in both pooled placebo groups; bSeventeen subjects who received tezacaftor 100 mg qday/ivacaftor 150 mg q12h were counted in both the dose escalation and dosage regimen testing phases.

Figure E2. Efficacy in Subjects Compound Heterozygous for F508del and G551DMean absolute changes in ppFEV1 for the treatment and washout periods (A) and individual subject absolute changes in ppFEV1 at day 28 for the tezacaftor 100 mg qday + ivacaftor 150 mg q12h (B) and placebo (C) cohorts. Analysis of change from baseline at all measurements up to day 28 was based on a mixed-effect model for repeated measures. For the washout period, summary statistics are shown. LS=least squares; ppFEV1=percent predicted forced expiratory volume in 1 second.