The following adverse reaction is discussed in greater detail in other sections of the label:

• Transaminase Elevations [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

The overall safety profile of KALYDECO is based on pooled data from placebo-controlled clinical trials conducted in 353 patients with CF who had a G551D mutation in the CFTR gene or were homozygous for the F508del mutation. Of the 353 patients, 50% of patients were female and 97% were Caucasian; 221 received KALYDECO and 132 received placebo from 16 to 48 weeks. Patients treated with KALYDECO were between the ages of 6 and 53 years.

In these trials, the proportion of patients who prematurely discontinued study drug due to adverse reactions was 2% for KALYDECO-treated patients and 5% for placebo-treated patients. Serious adverse reactions, whether considered drug-related or not by the investigators, which occurred more frequently in KALYDECO-treated patients included abdominal pain, increased hepatic enzymes, and hypoglycemia.

Overall, the most common adverse reactions in 221 patients with CF who had either a G551D mutation or were homozygous for the F508del mutation in the CFTR and treated with KALYDECO were headache (17%), upper respiratory tract infection (16%), nasal congestion (16%), nausea (10%), rash (10%), rhinitis (6%), dizziness (5%), arthralgia (5%), and bacteria in sputum (5%).

The incidence of adverse reactions below is based upon two double-blind, placebo-controlled 48-week clinical trials in a total of 213 patients with CF ages 6 to 53 who have a G551D mutation in the CFTR gene and who were treated with KALYDECO 150 mg orally or placebo twice daily. Table 1 shows adverse reactions occurring in ≥8% of KALYDECO-treated patients with CF who have a G551D mutation in the CFTR gene that also occurred at a higher rate than in the placebo-treated patients in the two double-blind, placebo-controlled trials.

Table 1: Incidence of Adverse Drug Reactions in ≥8% of KALYDECO-Treated Patients with a G551D Mutation in the CFTR Gene and Greater than Placebo in 2 Placebo-Controlled Phase 3 Clinical Trials of 48 Weeks Duration

Adverse reactions that occurred in the KALYDECO group at a frequency of 4 to 7% where rates exceeded that in the placebo group include:

Infections and infestations: rhinitis

Investigations: aspartate aminotransferase increased, bacteria in sputum, blood glucose increased, hepatic enzyme increased

Musculoskeletal and connective tissue disorders: arthralgia, musculoskeletal chest pain, myalgia

Nervous system disorders: sinus headache

Respiratory, thoracic and mediastinal disorders: pharyngeal erythema, pleuritic pain, sinus congestion, wheezing

Skin and subcutaneous tissue disorders: acne

Laboratory Abnormalities

Transaminase Elevations: During 48-week, placebo-controlled clinical studies, the incidence of maximum transaminase (ALT or AST) >8, >5 or >3 x ULN was 2%, 3% and 6% in KALYDECO-treated patients and 2%, 2% and 8% in placebo-treated patients, respectively. Two patients (2%) on placebo and 1 patient (0.5 %) on KALYDECO permanently discontinued treatment for elevated transaminases, all >8x ULN. Two patients treated with KALYDECO were reported to have serious adverse reactions of elevated liver transaminases compared to none on placebo [see WARNINGS AND PRECAUTIONS].

Read the Kalydeco (ivacaftor) Side Effects Center for a complete guide to possible side effects »

Potential for other drugs to affect ivacaftor

Inhibitors of CYP3A

Ivacaftor is a sensitive CYP3A substrate. Co-administration with ketoconazole, a strong CYP3A inhibitor, significantly increased ivacaftor exposure [measured as area under the curve (AUC)] by 8.5-fold. Therefore, a reduction of the KALYDECO dose to 150 mg twice-a-week is recommended for coadministration with strong CYP3A inhibitors, such as ketoconazole, itraconazole, posaconazole, voriconazole, telithromycin, and clarithromycin.

Co-administration with fluconazole, a moderate inhibitor of CYP3A, increased ivacaftor exposure by 3-fold. Therefore, a reduction of the KALYDECO dose to 150 mg once daily is recommended for patients taking concomitant moderate CYP3A inhibitors, such as fluconazole and erythromycin.

Co-administration of KALYDECO with grapefruit juice, which contains one or more components that moderately inhibit CYP3A, may increase exposure of ivacaftor. Therefore, food containing grapefruit or Seville oranges should be avoided during treatment with KALYDECO [see CLINICAL PHARMACOLOGY].

Inducers of CYP3A

Co-administration with rifampin, a strong CYP3A inducer, significantly decreased ivacaftor exposure (AUC) by approximately 9-fold. Therefore, coadministration with strong CYP3A inducers, such as rifampin, rifabutin, phenobarbital, carbamazepine, phenytoin, and St. John's Wort is not recommended [see WARNINGS AND PRECAUTIONS and CLINICAL PHARMACOLOGY].

Potential for ivacaftor to affect other drugs

CYP3A and/or P-gp Substrates

Ivacaftor and its M1 metabolite have the potential to inhibit CYP3A and P-gp. Co-administration with midazolam, a sensitive CYP3A substrate, increased midazolam exposure 1.5-fold, consistent with weak inhibition of CYP3A by ivacaftor. Administration of KALYDECO may increase systemic exposure of drugs which are substrates of CYP3A and/or P-gp, which may increase or prolong their therapeutic effect and adverse events. Therefore, caution is recommended when co-administering KALYDECO with CYP3A and/or P-gp substrates, such as digoxin, cyclosporine, and tacrolimus [see CLINICAL PHARMACOLOGY].

Last reviewed on RxList: 10/10/2012
This monograph has been modified to include the generic and brand name in many instances.