Pharmacotherapeutic group: Other respiratory system products; ATC code: R07AX30
Mechanism of action
The CFTR protein is a chloride channel present at the surface of epithelial cells in multiple organs. The F508del mutation impacts the CFTR protein in multiple ways, primarily by causing a defect in cellular processing and trafficking that reduces the quantity of CFTR at the cell surface. The small amount of F508del-CFTR that reaches the cell surface has low channel-open probability (defective channel gating). Lumacaftor is a CFTR corrector that acts directly on F508del-CFTR to improve its cellular processing and trafficking, thereby increasing the quantity of functional CFTR at the cell surface. Ivacaftor is a CFTR potentiator that facilitates increased chloride transport by potentiating the channel-open probability (or gating) of the CFTR protein at the cell surface. The combined effect of lumacaftor and ivacaftor is increased quantity and function of F508del-CFTR at the cell surface, resulting in increased chloride ion transport. The exact mechanisms by which lumacaftor improves cellular processing and trafficking of F508del-CFTR and ivacaftor potentiates F508del-CFTR are not known.
Pharmacodynamic effects
Effects on sweat chloride
Changes in sweat chloride in response to lumacaftor alone or in combination with ivacaftor were evaluated in a double-blind, placebo-controlled, phase 2 clinical trial in patients with CF aged 18 years and older. In this trial, 10 patients (homozygous for F508del-CFTR mutation) completed dosing with lumacaftor alone 400 mg q12h for 28 days followed by the addition of ivacaftor 250 mg q12h for an additional 28 days, and 25 patients (homozygous or heterozygous for F508del) completed dosing with placebo. The treatment difference between lumacaftor 400 mg q12h alone and placebo evaluated as mean change in sweat chloride from baseline to day 28 was statistically significant at -8.2 mmol/L (95% CI: -14, -2). The treatment difference between the combination of lumacaftor 400 mg/ivacaftor 250 mg q12h and placebo evaluated as mean change in sweat chloride from baseline to day 56 was statistically significant at -11 mmol/L (95% CI: -18, -4).
In trial 7 in patients homozygous for the F508del-CFTR mutation aged 6 to less than 12 years, the treatment difference (LS mean) in sweat chloride for the absolute change at week 24 as compared to placebo was -24.9 mmol/L (nominal P < 0.0001). The treatment difference (LS mean) in sweat chloride for the average absolute change at day 15 and at week 4 as compared to placebo was -20.8 mmol/L (95% CI: -23.4, -18.2; nominal P < 0.0001).
In trial 8 in patients homozygous for F508del-CFTR mutation aged 2 to 5 years, the mean absolute within-group change in sweat chloride from baseline at week 24 was -31.7 mmol/L (95% CI: -35.7, -27.6). In addition, the mean absolute change in sweat chloride from week 24 at week 26 following the 2-week washout period (to evaluate off-drug response) was an increase of 33.0 mmol/L (95% CI: 28.9, 37.1; nominal P < 0.0001), representing a return to baseline after treatment washout. At week 24, 16% of children had a reduction in sweat chloride below 60 mmol/L, and none below 30 mmol/L.
In trial 11 in patients homozygous for F508del-CFTR mutation aged 1 to less than 2 years, treatment with lumacaftor/ivacaftor demonstrated a reduction in sweat chloride at week 4 which was sustained through week 24. The mean absolute change from baseline in sweat chloride at week 24 was -29.1 (13.5) mmol/L (95% CI: -34.8, -23.4). In addition, the mean (SD) absolute change in sweat chloride from week 24 at week 26 following the 2-week washout period was 27.3 (11.1) mmol/L (95% CI: 22.3, 32.3). This change represents a return towards baseline after treatment washout.
Changes in FEV1
Changes in ppFEV1 in response to lumacaftor alone or in combination with ivacaftor were also evaluated in the double-blind, placebo-controlled, phase 2 trial in patients with CF aged 18 years and older. The treatment difference between lumacaftor 400 mg q12h alone and placebo evaluated as mean absolute change in ppFEV1 was -4.6 percentage points (95% CI: -9.6, 0.4) from baseline to day 28, 4.2 percentage points (95% CI: –1.3, 9.7) from baseline to day 56, and 7.7 percentage points (95% CI: 2.6, 12.8; statistically significant) from day 28 to day 56 (following the addition of ivacaftor to lumacaftor monotherapy).
Decrease in heart rate
During the 24-week, placebo-controlled, phase 3 studies, a maximum decrease in mean heart rate of 6 beats per minute (bpm) from baseline was observed on day 1 and day 15 around 4 to 6 hours after dosing. After day 15, heart rate was not monitored in the period after dosing in these studies. From week 4, the change in mean heart rate at pre-dose ranged from 1 to 2 bpm below baseline among patients treated with lumacaftor/ivacaftor. The percentage of patients with heart rate values < 50 bpm on treatment was 11% for patients who received lumacaftor/ivacaftor, compared to 4.9% for patients who received placebo.
Cardiac electrophysiology
No meaningful changes in QTc interval or blood pressure were observed in a thorough QT clinical study evaluating lumacaftor 600 mg once daily/ivacaftor 250 mg q12h and lumacaftor 1000 mg once daily/ivacaftor 450 mg q12h.
Clinical efficacy and safety
Trials in patients with CF aged 12 years and above who are homozygous for the F508del mutation in the CFTR gene
The efficacy of lumacaftor/ivacaftor in patients with CF who are homozygous for the F508del mutation in the CFTR gene was evaluated in two randomised, double-blind, placebo-controlled clinical trials of 1,108 clinically stable patients with CF, in which 737 patients were randomised to and dosed with lumacaftor/ivacaftor. Patients in both trials were randomised 1:1:1 to receive lumacaftor 600 mg once daily/ivacaftor 250 mg q12h, lumacaftor 400 mg q12h/ivacaftor 250 mg q12h, or placebo. Patients took the study drug with fat-containing food for 24 weeks in addition to their prescribed CF therapies (e.g., bronchodilators, inhaled antibiotics, dornase alfa, and hypertonic saline). Patients from these trials were eligible to roll over into a blinded extension study.
Trial 1 evaluated 549 patients with CF who were aged 12 years and older (mean age 25.1 years) with percent predicted FEV1 (ppFEV1) at screening between 40-90 (mean ppFEV1 60.7 at baseline [range: 31.1 to 94.0]). Trial 2 evaluated 559 patients aged 12 years and older (mean age 25.0 years) with ppFEV1 at screening between 40-90 (mean ppFEV1 60.5 at baseline [range: 31.3 to 99.8]). Patients with a history of colonisation with organisms such as Burkholderia cenocepacia, Burkholderia dolosa, or Mycobacterium abscessus or who had 3 or more abnormal liver function tests (ALT, AST, AP, GGT ≥ 3 times the ULN or total bilirubin ≥ 2 times the ULN) were excluded.
The primary efficacy endpoint in both studies was the absolute change from baseline in ppFEV1 at week 24. Other efficacy variables included relative change from baseline in ppFEV1, absolute change from baseline in BMI, absolute change from baseline in CFQ-R Respiratory Domain, the proportion of patients achieving ≥ 5% relative change from baseline in ppFEV1 at week 24, and the number of pulmonary exacerbations (including those requiring hospitalisation or IV antibiotic therapy) through week 24.
In both trials, treatment with lumacaftor/ivacaftor resulted in a statistically significant improvement in ppFEV1 (see Table 6). Mean improvement in ppFEV1 was rapid in onset (day 15) and sustained throughout the 24‑week treatment period. At day 15, the treatment difference between lumacaftor 400 mg/ivacaftor 250 mg q12h and placebo for the mean absolute change (95% CI) in ppFEV1 from baseline was 2.51 percentage points in the pooled trials 1 and 2 (P < 0.0001). Improvements in ppFEV1 were observed regardless of age, disease severity, sex, and geographic region. The phase 3 trials of lumacaftor/ivacaftor included 81 patients with ppFEV1 < 40 at baseline. The treatment difference in this subgroup was comparable to that observed in patients with ppFEV1 ≥ 40. At week 24, the treatment difference between lumacaftor 400 mg/ivacaftor 250 mg q12h and placebo for the mean absolute change (95% CI) in ppFEV1 from baseline in the pooled trials 1 and 2 were 3.39 percentage points (P = 0.0382) for patients with ppFEV1 < 40 and 2.47 percentage points (P < 0.0001) for patients with ppFEV1 ≥ 40.
Table 6: Summary of primary and key secondary outcomes in trial 1 and trial 2*
| | Trial 1 | Trial 2 | Pooled (trial 1 and trial 2) |
| Placebo (n = 184) | LUM 400 mg q12h/ IVA 250 mg q12h (n = 182) | Placebo (n = 187) | LUM 400 mg q12h/IVA 250 mg q12h (n = 187) | Placebo (n = 371) | LUM 400 mg q12h/IVA 250 mg q12h (n = 369) |
| Absolute change in ppFEV1 at week 24 (percentage points) | Treatment difference | – | 2.41 (P = 0.0003) † | – | 2.65 (P = 0.0011) † | – | 2.55 (P < 0.0001) |
| Within-group change | -0.73 (P = 0.2168) | 1.68 (P = 0.0051) | -0.02 (P = 0.9730) | 2.63 (P < 0.0001) | -0.39 (P < 0.3494) | 2.16 (P < 0.0001) |
| Relative change in ppFEV1 at week 24 (%) | Treatment difference | – | 4.15 (P = 0.0028)† | – | 4.69 (P = 0.0009)† | – | 4.4 (P < 0.0001) |
| Within-group change | -0.85 (P = 0.3934) | 3.3 (P = 0.0011) | 0.16 (P = 0.8793) | 4.85 (P < 0.0001) | -0.34 (P = 0.6375) | 4.1 (P < 0.0001) |
| Absolute change in BMI at week 24 (kg/m2) | Treatment difference | – | 0.13 (P = 0.1938) | – | 0.36 (P < 0.0001)† | – | 0.24 (P = 0.0004) |
| Within-group change | 0.19 (P = 0.0065) | 0.32 (P < 0.0001) | 0.07 (P = 0.2892) | 0.43 (P < 0.0001) | 0.13 (P = 0.0066) | 0.37 (P < 0.0001) |
| Absolute change in CFQ-R Respiratory Domain Score at week 24 (points) | Treatment difference | – | 1.5 (P = 0.3569) | – | 2.9 (P = 0.0736) | – | 2.2 (P = 0.0512) |
| Within-group change | 1.1 (P = 0.3423) | 2.6 (P = 0.0295) | 2.8 (P = 0.0152) | 5.7 (P < 0.0001) | 1.9 (P = 0.0213) | 4.1 (P < 0.0001) |
| Proportion of patients with ≥5% relative change in ppFEV1 at week 24 | % | 25% | 32% | 26% | 41% | 26% | 37% |
| Odds ratio | – | 1.43 (P = 0.1208) | – | 1.90 (P = 0.0032) | – | 1.66 (P = 0.0013) |
| Number of pulmonary exacerbations through week 24 | # of events (rate per 48 weeks) | 112 (1.07) | 73 (0.71) | 139 (1.18) | 79 (0.67) | 251 (1.14) | 152 (0.70) |
| Rate ratio | – | 0.66 (P = 0.0169) | – | 0.57 (P = 0.0002) | – | 0.61 (P < 0.0001) |
* In each study, a hierarchical testing procedure was performed within each active treatment arm for primary and secondary endpoints vs. placebo; at each step, P ≤ 0.0250 and all previous tests also meeting this level of significance was required for statistical significance.
† Indicates statistical significance confirmed in the hierarchical testing procedure.
At week 24, the proportion of patients who remained free from pulmonary exacerbations was significantly higher for patients treated with lumacaftor/ivacaftor compared with placebo. In the pooled analysis, the rate ratio of exacerbations through week 24 in subjects treated with lumacaftor/ivacaftor (lumacaftor 400 mg/ivacaftor 250 mg q12h; n = 369) was 0.61 (P < 0.0001), representing a reduction of 39% relative to placebo. The event rate per year, annualised to 48 weeks, was 0.70 in the lumacaftor/ivacaftor group and 1.14 in the placebo group. Treatment with lumacaftor/ivacaftor significantly decreased the risk for exacerbations requiring hospitalisation versus placebo by 61% (rate ratio = 0.39, P < 0.0001; event rate per 48 weeks 0.17 for lumacaftor/ivacaftor and 0.45 for placebo) and reduced exacerbations requiring treatment with intravenous antibiotics by 56% (rate ratio = 0.44, P < 0.0001; event rate per 48 weeks 0.25 for lumacaftor/ivacaftor and 0.58 for placebo). These results were not considered statistically significant within the framework of the testing hierarchy for the individual studies.
Long-term safety and efficacy rollover trial
Trial 3 was a phase 3, parallel‑group, multicentre, rollover extension study in patients with CF that included patients aged 12 years and older from trial 1 and trial 2. This extension trial was designed to evaluate the safety and efficacy of long-term treatment of lumacaftor/ivacaftor. Of the 1,108 patients who received any treatment in trial 1 or trial 2, 1,029 (93%) were dosed and received active treatment (lumacaftor 600 mg once daily/ivacaftor 250 mg q12h or lumacaftor 400 mg q12h/ivacaftor 250 mg q12h) in trial 3 for up to an additional 96 weeks (i.e., up to a total of 120 weeks). The primary efficacy analysis of this extension study included data up to week 72 of trial 3 with a sensitivity analysis that included data up to week 96 of trial 3.
Patients treated with lumacaftor/ivacaftor in trial 1 or trial 2 showed an effect that was maintained with respect to baseline after an additional 96 weeks through trial 3. For patients who transitioned from placebo to active treatment similar changes as those observed in patients treated with lumacaftor/ivacaftor in trial 1 or trial 2 were seen (see Table 6). Results from trial 3 are presented in Figure 1 and Table 7.
| Figure 1. Absolute change from baseline in percent predicted FEV1 at each visit† |
| |
| † From trials 1, 2, and 3. |
| Table 7: Long-term effect of lumacaftor/ivacaftor in trial 3* |
| | Placebo transitioned to lumacaftor 400 mg q12h/ ivacaftor 250 mg q12h (n = 176)** | lumacaftor 400 mg q12h/ ivacaftor 250 mg q12h (n = 369)† |
| Baseline and endpoint | Mean (SD) | LS Means (95% CI) | P value | Mean (SD) | LS Means (95% CI) | P value |
| Baseline ppFEV1‡ | 60.2 (14.7) | | | 60.5 (14.1) | | |
| Absolute change from baseline ppFEV1 (percentage points) |
| Extension week 72 | | (n = 134) 1.5 (0.2, 2.9) | 0.0254 | | (n = 273) 0.5 (-0.4, 1.5) | 0.2806 |
| Extension week 96 | | (n = 75) 0.8 (-0.8, 2.3) | 0.3495 | | (n = 147) 0.5 (-0.7, 1.6) | 0.4231 |
| Relative change from baseline ppFEV1 (%) |
| Extension week 72 | | (n = 134) 2.6 (0.2, 5.0) | 0.0332 | | (n = 273) 1.4 (-0.3, 3.2) | 0.1074 |
| Extension week 96 | | (n = 75) 1.1 (-1.7, 3.9) | 0.4415 | | (n = 147) 1.2 (-0.8, 3.3) | 0.2372 |
| Baseline BMI (kg/m2)‡ | 20.9 (2.8) | | | 21.5 (3.0) | | |
| Absolute change from baseline in BMI (kg/m2) |
| Extension week 72 | | (n = 145) 0.62 (0.45, 0.79) | < 0.0001 | | (n = 289) 0.69 (0.56, 0.81) | < 0.0001 |
| Extension week 96 | | (n = 80) 0.76 (0.56, 0.97) | < 0.0001 | | (n = 155) 0.96 (0.81, 1.11) | < 0.0001 |
| Baseline CFQ-R Respiratory Domain Score (points)‡ | 70.4 (18.5) | | | 68.3 (18.0) | | |
| Absolute change in CFQ-R Respiratory Domain Score (points) |
| Extension week 72 | | (n = 135) 3.3 (0.7, 5.9) | 0.0124 | | (n = 269) 5.7 (3.8, 7.5) | < 0.0001 |
| Extension week 96 | | (n = 81) 0.5 (-2.7, 3.6) | 0.7665 | | (n = 165) 3.5 (1.3, 5.8) | 0.0018 |
| Number of Pulmonary exacerbations (events) ** † *** |
| Number of events per patient- year (95% CI) (rate per 48 weeks) Number of events requiring hospitalisation per patient-year (95% CI) (rate per 48 weeks) Number of events requiring intravenous antibiotics per patient-year (95% CI) (rate per 48 weeks) | | 0.69 (0.56, 0.85) 0.30 (0.22, 0.40) 0.37 (0.29, 0.49) | | | 0.65 (0.56, 0.75) 0.24 (0.19, 0.29) 0.32 (0.26, 0.38) | |
* A total of 82% (421 of 516 eligible patients) completed 72 weeks of this study; 42% completed 96 weeks. Majority of patients discontinued for reasons other than safety.
** For patients rolled over from trials 1 and 2 (placebo-to-lumacaftor/ivacaftor group) total exposure was up to 96 weeks. Presentation of the lumacaftor 400 mg q12h/ivacaftor 250 mg q12h dose group is consistent with recommended posology.
*** The event rate per patient-year was annualised to 48 weeks.
† For patients rolled over from trials 1 and 2 (lumacaftor/ivacaftor-to-lumacaftor/ivacaftor group) total exposure was up to 120 weeks. Presentation of the lumacaftor 400 mg q12h/ivacaftor 250 mg q12h dose group is consistent with recommended posology.
‡ Baseline for the placebo transitioned to lumacaftor 400 mg q12h/ivacaftor 250 mg q12h group was the trial 3baseline. Baseline for the lumacaftor 400 mg q12h/ivacaftor 250 mg q12h group was the trial 1 and 2 baseline.
Trial in patients with CF who are heterozygous for the F508del mutation in the CFTR gene
Trial 4 was a multicentre, double–blind, randomised, placebo–controlled, phase 2 trial in 125 patients with CF aged 18 years and older who had a ppFEV1 of 40 to 90, inclusive, and have the F508del mutation on one allele plus a second allele with a mutation predicted to result in the lack of CFTR production or a CFTR that is not responsive to ivacaftor in vitro.
Patients received either lumacaftor/ivacaftor (n = 62) or placebo (n = 63) in addition to their prescribed CF therapies. The primary endpoint was improvement in lung function as determined by the mean absolute change from baseline at day 56 in ppFEV1. Treatment with lumacaftor/ivacaftor resulted in no significant improvement in ppFEV1 relative to placebo in patients with CF heterozygous for the F508del mutation in the CFTR gene (treatment difference 0.60 [P = 0.5978]) and no meaningful improvements in BMI or weight (see section 4.4).
Paediatric population
Trials in patients with CF aged 6 to less than 12 years old who are homozygous for the F508del mutation in the CFTR gene
Trial 7 was a 24-week, placebo-controlled, phase 3 clinical study in 204 patients with CF aged 6 to less than 12 years old (mean age 8.8 years). Trial 7 evaluated subjects with lung clearance index (LCI2.5) ≥ 7.5 at the initial screening visit (mean LCI2.5 10.28 at baseline [range: 6.55 to 16.38]) and ppFEV1 ≥ 70 at screening (mean ppFEV1 89.8 at baseline [range: 48.6 to 119.6]). Patients received either lumacaftor 200 mg/ivacaftor 250 mg every 12 hours (n = 103) or placebo (n = 101) in addition to their prescribed CF therapies. Patients who had 2 or more abnormal liver function tests (ALT, AST, AP, GGT ≥ 3 times the ULN), or ALT or AST > 5 times ULN, or total bilirubin > 2 times ULN were excluded.
The primary efficacy endpoint was absolute change in LCI2.5 from baseline through week 24. Key secondary endpoints included average absolute change from baseline in sweat chloride at day 15 and week 4 and at week 24 (see section 5.1 Pharmacodynamic effects), absolute change from baseline in BMI at week 24, absolute change from baseline in CFQ-R Respiratory Domain through week 24. These results are presented in Table 8 below:
Table 8: Summary of primary and key secondary outcomes in trial 7
| | Placebo (n = 101) | LUM 200 mg/IVA 250 mg q12h (n = 103) |
| Primary Endpoint |
| Absolute change in lung clearance index (LCI2.5) from baseline through week 24 | Treatment difference | – | -1.09 (P < 0.0001) |
| Within-group change | 0.08 (P = 0.5390) | -1.01 (P < 0.0001) |
| Key Secondary Endpoints* |
| Absolute change in BMI at week 24 (kg/m2) | Treatment difference | – | 0.11 (P = 0.2522) |
| Within-group change | 0.27 (P = 0.0002) | 0.38 (P < 0.0001) |
| Absolute change in CFQ-R Respiratory Domain Score through week 24 (points) | Treatment difference | – | 2.5 (P = 0.0628) |
| Within-group change | 3.0 (P = 0.0035) | 5.5 (P < 0.0001) |
* Trial included key secondary and other secondary endpoints.
Percent predicted FEV1 was also evaluated as a clinically meaningful other secondary endpoint. In the lumacaftor/ivacaftor patients, the treatment difference for absolute change in ppFEV1 from baseline through week 24 was 2.4 (P = 0.0182).
Patients with CF aged 6 years and older from trial 6 and trial 7 were included in a phase 3, multicentre, rollover extension study (trial 9). This extension trial was designed to evaluate the safety and efficacy of long-term treatment of lumacaftor/ivacaftor. Of the 262 patients who received any treatment in trial 6 or trial 7, 239 (91%) were dosed and received active treatment (patients 6 to less than 12 years of age received lumacaftor 200 mg q12h/ivacaftor 250 mg q12h; patients ≥12 years of age received lumacaftor 400 mg q12h/ivacaftor 250 mg q12h) in the extension study for up to an additional 96 weeks (i.e., up to a total of 120 weeks) (see section 4.8). Secondary efficacy results and pulmonary exacerbation event rate per patient year are presented in Table 9.
| Table 9: Long-term effect of lumacaftor/ivacaftor in trial 9 |
| | Placebo transitioned to lumacaftor / ivacaftor (P-L/I) (n = 96)* | lumacaftor / ivacaftor – lumacaftor / ivacaftor (L/I-L/I) (n = 143)* |
| Baseline and endpoint | Mean (SD) | LS Mean (95% CI) | Mean (SD) | LS Mean (95% CI) |
| | n = 101 | | n = 128 | |
| Baseline LCI2.5‡** | 10.26 (2.24) | | 10.24 (2.42) | |
| Absolute change from baseline in LCI2.5 |
| Extension week 96 | | (n = 69) -0.86 (-1.33, -0.38) | | (n = 88) -0.85 (-1.25, -0.45) |
| | n = 101 | | n = 161 | |
| Baseline BMI (kg/m2)‡ | 16.55 (1.96) | | 16.56 (1.77) | |
| Absolute change from baseline in BMI (kg/m2) |
| Extension week 96 | | (n = 83) 2.04 (1.77, 2.31) | | (n =130) 1.78 (1.56, 1.99) |
| | n = 78 | | n = 135 | |
| Baseline CFQ-R‡ Respiratory Domain Score (points) | 77.1 (15.5) | | 78.5 (14.3) | |
| Absolute change in CFQ-R Respiratory Domain Score (points) |
| Extension week 96 | | (n = 65) 6.6 (3.1, 10.0) | | (n = 108) 7.4 (4.8, 10.0) |
| Number of pulmonary exacerbations (events) (trial 7 FAS and ROS)† |
| Number of events per patient- year (95% CI) | | n = 96 0.30 (0.21, 0.43) | | n = 103 0.45 (0.33, 0.61) |
| *Subjects treated with placebo in trial 7 (n=96) and transitioned onto active LUM/IVA treatment in the extension study (P-L/I). Subjects treated with LUM/IVA in either parent study [trial 6 (n=49) or trial 7 (n=94)] and continued active LUM/IVA treatment in the extension (L/I-L/I). ‡Baseline for both groups (P-L/I and L/I-L/I) was the trial 6 and trial 7 (parent study) baseline and the corresponding n refers to the analysis set in the parent study. **The LCI sub-study included 117 subjects in the L/I-L/I group and 96 subjects in the P-L/I group. †FAS = Full Analysis Set (n=103) includes subjects who received L/I in trial 7 and in trial 9, assessed over the cumulative study period for L/I; ROS = Rollover Set (n=96) includes subjects who received placebo in trial 7 and L/I in trial 9, assessed over the current study period for trial 9. |
Trial 8: Safety and tolerability study in paediatric patients with CF aged 2 to 5 years homozygous for the F508del mutation in the CFTR gene
Trial 8 evaluated 60 patients aged 2 to 5 years at screening (mean age at baseline 3.7 years). According to their weight at screening, patients were administered granules mixed with food every 12 hours, at a dose of lumacaftor 100 mg/ivacaftor 125 mg granules for patients weighing less than14 kg (n = 19) or lumacaftor 150 mg/ivacaftor 188 mg for patients weighing 14 kg or greater (n = 41), for 24 weeks in addition to their prescribed CF therapies. In order to evaluate off drug effects, patients had a safety follow-up visit following a 2-week washout period.
Secondary endpoints included absolute change from baseline in sweat chloride at week 24 and absolute change in sweat chloride from week 24 at week 26 (see section 5.1 Pharmacodynamic effects) as well as the endpoints listed in Table 10. The clinical relevance of the magnitude of these changes in children 2 to 5 years with cystic fibrosis has not been clearly ascertained in longer-term treatment.
Table 10: Summary of secondary outcomes in trial 8
| Secondary endpoints* | LUM/IVA |
| Absolute change from baseline in body mass index (BMI) | n = 57 0.27 95% CI: 0.07, 0.47; P = 0.0091 |
| Absolute change from baseline in BMI-for-age z-score | n = 57 0.29 95% CI: 0.14, 0.45; P = 0.0003 |
| Absolute change from baseline in weight (kg) | n = 57 1.4 95% CI: 1.2, 1.7; P < 0.0001 |
| Absolute change from baseline in weight-for-age z-score | n = 57 0.26 95% CI: 0.15, 0.38; P < 0.0001 |
| Absolute change from baseline in stature (cm) | n = 57 3.6 95% CI: 3.3, 3.9; P < 0.0001 |
| Absolute change from baseline in stature-for-age z-score | n = 57 0.09 95% CI: 0.02, 0.15; P = 0.0104 |
| Absolute change from baseline in faecal elastase-1 (FE-1) levels (µg/g)** | n = 35 52.6 95% CI: 22.5, 82.7; P = 0.0012 |
| LCI 2.5 | n = 17 -0.58 95% CI: -1.17, 0.02; P = 0.0559 |
Note: P values in the table are nominal.
* For the endpoints listed, absolute change from baseline is the mean absolute change from baseline at week 24.
** All patients had pancreatic insufficiency at baseline. Three of the 48 patients who had faecal elastase-1 values < 100 µg/g at baseline achieved a level of ≥ 200 µg/g at week 24.
Trial 11: Safety and tolerability study in paediatric patients with CF aged 1 to less than 2 years homozygous for the F508del mutation in the CFTR gene
Trial 11 was a single-arm, uncontrolled, trial evaluating the pharmacokinetic profile, pharmacodynamic effects and safety of lumacaftor/ivacaftor in 46 patients with CF aged 1 to less than 2 years (mean age at baseline18.1 months). The pharmacodynamic effects observed in this study are similar to effects observed in patients aged 12 years and older (trials 1 and 2). The efficacy of lumacaftor/ivacaftor in patients aged 1 to less than 2 years is extrapolated from patients aged 12 years and older.
In trial 11 Part B the primary endpoint of safety and tolerability was evaluated across 24 weeks. Secondary endpoints evaluated were pharmacokinetics and absolute change from baseline in sweat chloride at week 24 (see section 5.1 Pharmacodynamic effects). According to their weight at screening, patients were administered granules mixed with food every 12 hours for 24 weeks, at a dose of lumacaftor75 mg/ivacaftor 94 mg granules (one patient weighing 7 kg to < 9 kg) or lumacaftor 100 mg/ivacaftor 125 mg granules (44 patients weighing 9 kg to <14 kg) or lumacaftor 150 mg /ivacaftor 188 mg granules (one patient weighing ≥14 kg), in addition to their prescribed CF therapies. In order to evaluate off-drug effects, patients had a safety follow-up visit following a 2-week washout period. Tertiary endpoints included efficacy measures such as faecal elastase-1, immunoreactive trypsinogen (IRT), and growth parameters (see Table 11).
Table 11: Summary of tertiary outcomes listed in trial 11
| Tertiary endpoints* | LUM/IVA |
| Absolute change from baseline in BMI-for-age-z-score | n = 38 0.04 95% CI: (-0.14, 0.22) |
| Absolute change from baseline in weight-for-age z-score | n = 38 0.06 95% CI: (-0.05, 0.17) |
| Absolute change from baseline in weight-for-length-z-score | n = 38 0.04 95% CI: (-0.13, 0.22) |
| Absolute change from baseline in length-for-age z-score | n = 38 0.07 95% CI: (-0.11, 0.24) |
| Absolute change from baseline in faecal elastase-1 (FE-1) levels (mg/kg)** | n = 28 73.1 95% CI: (29.4, 116.8) |
| Absolute change from baseline in serum levels of immunoreactive trypsinogen (IRT) (μg/L) | n = 31 -295.5 95% CI: (-416.6, -174.5) |
| *For all endpoints listed, absolute change from baseline is the mean absolute change from baseline at week 24. **Of the 28 subjects with both baseline and week 24 FE-1 levels (all of which were <200 mg/kg at baseline), 4 (14.3%) had levels ≥200 mg/kg at week 24. |
The MHRA has deferred the obligation to submit the results of studies with Orkambi in one or more subsets of the paediatric population in cystic fibrosis (see section 4.2 for information on paediatric use).