Ibrutinib

Administration of ibrutinib with inducers of CYP3A4 can decrease ibrutinib plasma
concentrations.

Co-administration of rifampicin, a strong CYP3A4 inducer, in 18 fasted healthy subjects, decreased exposure (C_max and AUC) of ibrutinib by 92 and 90%, respectively. Avoid concomitant use of strong or moderate CYP3A4 inducers (e.g. carbamazepine, rifampicin, phenytoin). Preparations containing St. John’s Wort are contraindicated during treatment with ibrutinib, as efficacy may be reduced. Consider alternative agents with less CYP3A4 induction. If the benefit outweighs the risk and a strong or moderate CYP3A4 inducer must be used, monitor patient closely for lack of efficacy. Mild inducers may be used concomitantly with ibrutinib, however, patients should be monitored for potential lack of efficacy.

Based on in vitro data, ibrutinib is a weak reversible inhibitor towards CYP3A4 at the intestinal level and may therefore increase the exposure to CYP3A4 substrates sensitive to gut CYP3A metabolism. No clinical data are available on this interaction. Caution should be exercised if co-administering ibrutinib with CYP3A4 substrates administered orally with narrow therapeutic range (such as dihydroergotamine, ergotamine, fentanyl, cyclosporine, sirolimus and tacrolimus).

Based on in vitro data, ibrutinib is a weak CYP2B6 inducer and may have the potential to affect the expression of other enzymes and transporters regulated via the constitutive androstane receptor (CAR), e.g. CYP2C9, CYP2C19, UGT1A1 and MRP2. The clinical relevance is not known, but the exposure to substrates of CYP2B6 (such as efavirenz and bupropion) and of co-regulated enzymes may be reduced upon co-administration with ibrutinib.

Co-administration of grapefruit juice, containing CYP3A4 inhibitors, in eight healthy subjects, increased exposure (C_max and AUC) of ibrutinib by approximately 4- and 2-fold, respectively. Grapefruit and Seville oranges should be avoided during ibrutinib treatment, as these contain moderate inhibitors of CYP3A4.

Ibrutinib is a P-gp and breast cancer resistance protein (BCRP) inhibitor in vitro. As no clinical data are available on this interaction, it cannot be excluded that ibrutinib could inhibit intestinal P-gp and BCRP after a therapeutic dose. To minimise the potential for an interaction in the GI tract, oral narrow therapeutic range, P-gp or BCRP substrates such as digoxin or methotrexate should be taken at least 6 hours before or after ibrutinib. Ibrutinib may also inhibit BCRP in the liver and increase the exposure of medicinal products that undergo BCRP-mediated hepatic efflux, such as rosuvastatin.

Strong CYP3A4 inhibitors increase the exposure of ibrutinib.

The dose of ibrutinib should be reduced to 140 mg once daily or withheld for up to 7 days when it is used concomitantly with strong CYP3A4 inhibitors.

Co-administration of ketoconazole, a very strong CYP3A4 inhibitor, in 18 fasted healthy subjects, increased exposure (C_max and AUC) of ibrutinib by 29- and 24-fold, respectively. Simulations using fasted conditions suggested that the strong CYP3A4 inhibitor clarithromycin may increase the AUC of ibrutinib by a factor of 14. In patients with B-cell malignancies taking ibrutinib with food, co-administration of the strong CYP3A4 inhibitor voriconazole increased C_max by 6.7-fold and AUC by 5.7-fold. Strong inhibitors of CYP3A4 (e.g. ketoconazole, indinavir, nelfinavir, ritonavir, saquinavir, clarithromycin, telithromycin, itraconazole, nefazodon, cobicistat, voriconazole and posaconazole) should be avoided. If the benefit outweighs the risk and a strong CYP3A4 inhibitor must be used, reduce the ibrutinib dose to 140 mg for the duration of the inhibitor use or withhold ibrutinib temporarily (for 7 days or less). Monitor patient closely for toxicity and follow dose modification guidance as needed.

Moderate CYP3A4 inhibitors increase the exposure of ibrutinib.

The dose of ibrutinib should be reduced to 280 mg once daily when used concomitantly with moderate CYP3A4 inhibitors.

In patients with B-cell malignancies taking ibrutinib with food, co-administration of the
CYP3A4 inhibitor erythromycin increased C_max by 3.4-fold and AUC by 3.0-fold. If a moderate CYP3A4 inhibitor (e.g. fluconazole, erythromycin, amprenavir, aprepitant, atazanavir, ciprofloxacin, crizotinib, diltiazem, fosamprenavir, imatinib, verapamil, amiodarone and dronedarone) is indicated, reduce ibrutinib dose to 280 mg for the duration of the inhibitor use. Monitor patient closely for toxicity and follow dose modification guidance as needed.

Simulations using fasted conditions suggested that the mild CYP3A4 inhibitors azithromycin and fluvoxamine may increase the AUC of ibrutinib by <2-fold. No dose adjustment is required in combination with mild inhibitors. Monitor patient closely for toxicity and follow dose modification guidance as needed.

Hydration should be maintained and serum creatinine levels monitored periodically. Administer ibrutinib to patients with severe renal impairment (<30 mL/min creatinine clearance) only if the benefit outweighs the risk and monitor patients closely for signs of toxicity. There are no data in patients with severe renal impairment or patients on dialysis.

Ibrutinib is metabolised in the liver. In a hepatic impairment study, data showed an increase in ibrutinib exposure. For patients with mild liver impairment (Child-Pugh class A), the recommended dose is 280 mg daily.

Ibrutinib is metabolised in the liver. In a hepatic impairment study, data showed an increase in ibrutinib exposure. For patients with moderate liver impairment (Child-Pugh class B), the recommended dose is 140 mg daily. Monitor patients for signs of ibrutinib toxicity and follow dose modification guidance as needed.

Ibrutinib is metabolised in the liver. In a hepatic impairment study, data showed an increase in ibrutinib exposure. It is not recommended to administer ibrutinib to patients with severe hepatic impairment (Child-Pugh class C).

Use of either anticoagulants or medicinal products that inhibit platelet function (antiplatelet agents) concomitantly with ibrutinib increases the risk of major bleeding. A higher risk for major bleeding was observed with anticoagulant than with antiplatelet agents. Consider the risks and benefits of anticoagulant or antiplatelet therapy when co-administered with ibrutinib. Monitor for signs and symptoms of bleeding.

Warfarin or other vitamin K antagonists should not be administered concomitantly with ibrutinib.

There have been reports of bleeding events in patients treated with ibrutinib, both with and without thrombocytopenia. These include minor bleeding events such as contusion, epistaxis, and petechiae; and major bleeding events, some fatal, including gastrointestinal bleeding, intracranial haemorrhage, and haematuria.

Hypertension has occurred in patients treated with ibrutinib. Regularly monitor blood pressure in patients treated with ibrutinib and initiate or adjust antihypertensive medication throughout treatment with ibrutinib as appropriate.

Cases of interstitial lung disease have been reported in patients treated with ibrutinib. Monitor patients for pulmonary symptoms indicative of ILD. If symptoms develop, interrupt ibrutinib and manage ILD appropriately. If symptoms persist, consider the risks and benefits of ibrutinib treatment and follow the dose modification guidelines.

Cases of cerebrovascular accident, transient ischaemic attack and ischaemic stroke including fatalities have been reported with the use of ibrutinib, with and without concomitant atrial fibrillation and/or hypertension. Latency from the initiation of treatment with ibrutinib to the onset of ischaemic central nervous vascular conditions was in the most cases after several months (more than 1 month in 78% and more than 6 months in 44% of cases) emphasising the need for regular monitoring of patients.

Tumour lysis syndrome has been reported with ibrutinib therapy. Patients at risk of tumour lysis syndrome are those with high tumour burden prior to treatment. Monitor patients closely and take appropriate precautions.

Cases of leukostasis have been reported in patients treated with ibrutinib. A high number of circulating lymphocytes (>400,000/mcL) may confer increased risk. Consider temporarily withholding ibrutinib. Patients should be closely monitored. Administer supportive care including hydration and/or cytoreduction as indicated.

Non-melanoma skin cancers were reported more frequently in patients treated with ibrutinib than in patients treated with comparators in pooled comparative randomised phase 3 studies. Monitor patients for the appearance of non-melanoma skin cancer.

Ibrutinib should be held at least 3 to 7 days pre- and post-surgery depending upon the type of surgery and the risk of bleeding.

Infections (including sepsis, neutropenic sepsis, bacterial, viral, or fungal infections) were observed in patients treated with ibrutinib. Some of these infections have been associated with hospitalisation and death. Most patients with fatal infections also had neutropenia. Patients should be monitored for fever, neutropenia and infections and appropriate anti-infective therapy should be instituted as indicated. Consider prophylaxis according to standard of care in patients who are at increased risk for opportunistic infections.

Cases of invasive fungal infections, including cases of Aspergillosis, Cryptococcosis and Pneumocystis jiroveci infections have been reported following the use of ibrutinib. Reported cases of invasive fungal infections have been associated with fatal outcomes.

Cases of progressive multifocal leukoencephalopathy (PML) including fatal ones have been reported following the use of ibrutinib within the context of a prior or concomitant immunosuppressive therapy. Physicians should consider PML in the differential diagnosis in patients with new or worsening neurological, cognitive or behavioral signs or symptoms. If PML is suspected then appropriate diagnostic evaluations should be undertaken and treatment suspended until PML is excluded. If any doubt exists, referral to a neurologist and appropriate diagnostic measures for PML including MRI scan preferably with contrast, cerebrospinal fluid (CSF) testing for JC Viral DNA and repeat neurological assessments should be considered.

Cases of hepatitis B reactivation have been reported in patients receiving ibrutinib. Hepatitis B virus (HBV) status should be established before initiating treatment with ibrutinib. For patients who test positive for HBV infection, consultation with a physician with expertise in the treatment of hepatitis B is recommended. If patients have positive hepatitis B serology, a liver disease expert should be consulted before the start of treatment and the patient should be monitored and managed following local medical standards to prevent hepatitis B reactivation.

Ibrutinib therapy should be withheld for any new onset or worsening grade ≥3 non-haematological toxicity, grade 3 or greater neutropenia with infection or fever, or grade 4 haematological toxicities. Once the symptoms of the toxicity have resolved to grade 1 or baseline (recovery), ibrutinib therapy may be reinitiated at the starting dose. If the toxicity reoccurs, the once daily dose should be reduced by one capsule (140 mg). A second reduction of dose by 140 mg may be considered as needed. If these toxicities persist or recur following two dose reductions, discontinue the medicinal product.

Recommended dose modifications are described below:

Atrial fibrillation, atrial flutter and cases of ventricular tachyarrhythmia have been reported in patients treated with ibrutinib. Cases of atrial fibrillation and atrial flutter have been reported particularly in patients with cardiac risk factors, hypertension, acute infections, and a previous history of atrial fibrillation. Periodically monitor all patients clinically for cardiac arrhythmia. Patients who develop arrhythmic symptoms or new onset of dyspnoea, dizziness or fainting should be evaluated clinically and if indicated have an electrocardiogram (ECG) performed.

In patients who develop signs and/or symptoms of ventricular tachyarrhythmia, ibrutinib should be temporarily discontinued and a thorough clinical benefit/risk assessment should be performed before possibly restarting therapy.

In patients with preexisting atrial fibrillation requiring anticoagulant therapy, alternative treatment options to ibrutinib should be considered. In patients who develop atrial fibrillation on therapy with ibrutinib a thorough assessment of the risk for thromboembolic disease should be undertaken. In patients at high risk and where alternatives to ibrutinib are non-suitable, tightly controlled treatment with anticoagulants should be considered.

Treatment-emergent grade 3 or 4 cytopenias (neutropenia, thrombocytopenia and anaemia) were reported in patients treated with ibrutinib. Monitor complete blood counts monthly.

Supplements such as fish oil and vitamin E preparations should be avoided in co-administration with ibrutinib.

Ibrutinib should not be used during pregnancy. There are no data from the use of ibrutinib in pregnant women. Studies in animals have shown reproductive toxicity.

It is not known whether ibrutinib or its metabolites are excreted in human milk. A risk to breast-fed children cannot be excluded. Breast-feeding should be discontinued during treatment with ibrutinib.

Women of child-bearing potential/Contraception in females

Based on findings in animals, ibrutinib may cause foetal harm when administered to pregnant women. Women should avoid becoming pregnant while taking ibrutinib and for up to 3 months after ending treatment. Therefore, women of child-bearing potential must use highly effective contraceptive measures while taking ibrutinib and for three months after stopping treatment. It is currently unknown whether ibrutinib may reduce the effectiveness of hormonal contraceptives, and therefore women using hormonal contraceptives should add a barrier method.

Fertility

No effects on fertility or reproductive capacities were observed in male or female rats up to the maximum dose tested, 100 mg/kg/day (Human Equivalent Dose [HED] 16 mg/kg/day). No human data on the effects of ibrutinib on fertility are available.

Ibrutinib has minor influence on the ability to drive and use machines.

Fatigue, dizziness and asthenia have been reported in some patients taking ibrutinib and should be considered when assessing a patient’s ability to drive or operate machines.

Summary of the safety profile

The safety profile is based on pooled data from 1200 patients treated with ibrutinib in three phase 2 clinical studies and six randomised phase 3 studies and from post-marketing experience. Patients treated for MCL in clinical studies received ibrutinib at 560 mg once daily and patients treated for CLL or WM in clinical studies received ibrutinib at 420 mg once daily. All patients in clinical studies received ibrutinib until disease progression or no longer tolerated.

The most commonly occurring adverse reactions (≥20%) were diarrhoea, rash, haemorrhage (e.g. bruising), neutropenia, musculoskeletal pain, nausea, and thrombocytopenia. The most common grade ¾ adverse reactions (≥5%) were neutropenia, pneumonia, and thrombocytopenia.

Tabulated list of adverse reactions

Adverse reactions in patients treated with ibrutinib for B-cell malignancies and post-marketing adverse reactions are listed below by system organ class and frequency grouping. Frequencies are defined as follows: very common (≥1/10), common (≥1/100 to <1/10), uncommon (≥1/1,000 to <1/100), rare (≥1/10,000 to <1/1,000), not known (cannot be estimated from the available data). Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness.

Adverse reactions reported in clinical studies or during post marketing surveillance in patients with B-cell malignancies†:

^† Frequencies are rounded to the nearest integer.
* Includes multiple adverse reaction terms.
^# Includes events with fatal outcome.
^@ Lower level term (LLT) used for selection.
^a Spontaneous reports from post-marketing experience.
^b Frequency calculated from monotherapy clinical studies.

Description of selected adverse reactions

Discontinuation and dose reduction due to adverse reactions

Of the 1200 patients treated with ibrutinib for B-cell malignancies, 5% discontinued treatment primarily due to adverse reactions. These included pneumonia, atrial fibrillation, haemorrhage, and thrombocytopenia. Adverse reactions leading to dose reduction occurred in approximately 7% of patients.

Elderly

Of the 1200 patients treated with ibrutinib, 64% were 65 years of age or older. Grade 3 or higher pneumonia occurred more frequently among elderly patients treated with ibrutinib (12% of patients age ≥65 versus 7% of patients <65 years of age).

Long-term safety

The long-term safety data over 5 years from 1178 patients (treatment-naïve CLL/SLL n=162, relapsed/refractory CLL/SLL n=646, and relapsed/refractory MCL n=370) treated with ibrutinib were analysed. The median duration of treatment for CLL/SLL was 51 months (range, 0.2 to 98 months) with 70% and 52% of patients receiving treatment for more than 2 years and 4 years, respectively. The median duration of treatment for MCL was 11 months (range, 0 to 87 months) with 31% and 17% of patients receiving treatment for more than 2 years and 4 years, respectively. The overall known safety profile of ibrutinib-exposed patients remained consistent, other than an increasing prevalence of hypertension, with no new safety concerns identified. The prevalence for Grade 3 or greater hypertension was 4% (year 0-1), 6% (year 1-2), 8% (year 2-3), 9% (year 3-4), and 9% (year 4-5). The incidence for the 5-year period was 11%.