Bosutinib

In vitro studies indicate that bosutinib has a low potential to inhibit breast cancer resistance protein (BCRP, systemically), organic anion transporting polypeptide (OATP)1B1, OATP1B3, organic anion transporter (OAT)1, OAT3, organic cation transporter (OCT)2 at clinically relevant concentrations, but may have the potential to inhibit BCRP in the gastrointestinal tract and OCT1.

Bosutinib should be used with caution in patients who have or may develop prolongation of QT, including those patients taking anti-arrhythmic medicinal products such as amiodarone, disopyramide, procainamide, quinidine and sotalol or other medicinal products that may lead to QT prolongation such as chloroquine, halofantrine, clarithromycin, domperidone, haloperidol, methadone, and moxifloxacin.

Automated machine-read QTc prolongation without accompanying arrhythmia has been observed. Bosutinib should be administered with caution to patients who have a history of or predisposition for QTc prolongation, who have uncontrolled or significant cardiac disease including recent myocardial infarction, congestive heart failure, unstable angina or clinically significant bradycardia, or who are taking medicinal products that are known to prolong the QTc (e.g., anti-arrhythmic medicinal products and other substances that may prolong QTc). The presence of hypokalaemia and hypomagnesaemia may further enhance this effect.

Monitoring for an effect on the QTc is advisable and a baseline electrocardiogram (ECG) is recommended prior to initiating therapy with bosutinib and as clinically indicated. Hypokalaemia or hypomagnesaemia must be corrected prior to bosutinib administration and should be monitored periodically during therapy.

The concomitant use of bosutinib with strong CYP3A inducers (including, but not limited to carbamazepine, phenytoin, rifampicin, St. John's Wort), or moderate CYP3A inducers (including, but not limited to bosentan, efavirenz, etravirine, modafinil, nafcillin) should be avoided, as a decrease in bosutinib plasma concentration will occur.

Based on the large reduction in bosutinib exposure that occurred when bosutinib was co-administered with rifampicin, increasing the dose of bosutinib when co-administering with strong or moderate CYP3A inducers is unlikely to sufficiently compensate for the loss of exposure.

Caution is warranted if mild CYP3A inducers are used concomitantly with bosutinib.

Following concomitant administration of a single dose bosutinib with 6 daily doses of 600 mg rifampicin, in 24 healthy subjects in fed state bosutinib exposure (C_max and AUC in plasma) decreased to 14% and 6%, respectively, of the values when bosutinib 500 mg was administered alone.

The concomitant use of bosutinib with strong CYP3A inhibitors (including, but not limited to itraconazole, ketoconazole, posaconazole, voriconazole, clarithromycin, telithromycin, nefazodone, mibefradil, indinavir, lopinavir/ritonavir, nelfinavir, ritonavir, saquinavir, boceprevir, telaprevir, grapefruit products including grapefruit juice) or moderate CYP3A inhibitors (including, but not limited to fluconazole, ciprofloxacin, erythromycin, diltiazem, verapamil, amprenavir, atazanavir, darunavir/ritonavir, fosamprenavir, aprepitant, crizotinib, imatinib) should be avoided, as an increase in bosutinib plasma concentration will occur.

Caution should be exercised if mild CYP3A inhibitors are used concomitantly with bosutinib.

Selection of an alternate concomitant medicinal product with no or minimal CYP3A enzyme inhibition potential, if possible, is recommended.

If a strong or moderate CYP3A inhibitor must be administered during bosutinib treatment, an interruption of bosutinib therapy or a dose reduction in bosutinib should be considered.

In a study of 24 healthy subjects in whom 5 daily doses of 400 mg ketoconazole (a strong CYP3A inhibitor) were co-administered with a single dose of 100 mg bosutinib under fasting conditions, ketoconazole increased bosutinib C_max by 5.2-fold, and bosutinib AUC in plasma by 8.6-fold, as compared with administration of bosutinib alone.

In a study of 20 healthy subjects, in whom a single dose of 125 mg aprepitant (a moderate CYP3A inhibitor) was co-administered with a single dose of 500 mg bosutinib under fed conditions, aprepitant increased bosutinib C_max by 1.5-fold, and bosutinib AUC in plasma by 2.0-fold, as compared with administration of bosutinib alone.

Treatment with bosutinib may result in a clinically significant decline in renal function in CML adult and paediatric patients. A decline over time in estimated glomerular filtration rate (eGFR) has been observed in patients treated with bosutinib in clinical studies.

It is important that renal function is assessed prior to treatment initiation and closely monitored during therapy with bosutinib, with particular attention in those patients who have preexisting renal compromise or in those patients exhibiting risk factors for renal dysfunction, including concomitant use of medicinal products with potential for nephrotoxicity, such as diuretics, angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers, and nonsteroidal anti-inflammatory drugs (NSAIDs).

In a renal impairment study, bosutinib exposures were increased in subjects with moderately and severely impaired renal function. Dose reduction is recommended for patients with moderate or severe renal impairment.

Patients with serum creatinine >1.5 × ULN were excluded from the CML studies.

Clinical data are very limited (n=3) for CML patients with moderate renal impairment receiving an escalated dose of 600 mg bosutinib.

Caution should be exercised when administering bosutinib concomitantly with PPIs. Short-acting antacids should be considered as an alternative to PPIs and administration times of bosutinib and antacids should be separated (i.e. take bosutinib in the morning and antacids in the evening) whenever possible. Bosutinib displays pH-dependent aqueous solubility in vitro. When a single oral dose of bosutinib (400 mg) was co-administered with multiple-oral doses of lansoprazole (60 mg) in a study of 24 healthy fasting subjects, bosutinib C_max and AUC decreased to 54% and 74%, respectively, of the values seen when bosutinib (400 mg) was given alone.

Based on non-clinical findings, bosutinib has the potential to impair reproductive function and fertility in humans. Men being treated with bosutinib are advised to seek advice on conservation of sperm prior to treatment because of the possibility of decreased fertility due to therapy with bosutinib.

Treatment with bosutinib in adult and paediatric patients is associated with diarrhoea and vomiting; therefore, patients with recent or ongoing clinically significant gastrointestinal disorder should use this medicinal product with caution and only after a careful benefit-risk assessment as respective patients were excluded from the clinical studies.

Elevation in serum lipase has been observed. Caution is recommended in patients with previous history of pancreatitis.

There are limited amount of data in pregnant women from the use of bosutinib. Studies in animals have shown reproductive toxicity. Bosutinib is not recommended for use during pregnancy, or in women of childbearing potential not using contraception. If bosutinib is used during pregnancy, or the patient becomes pregnant while taking bosutinib, she should be apprised of the potential hazard to the foetus.

It is unknown whether bosutinib and its metabolites are excreted in human milk. A study of [¹⁴C] radiolabelled bosutinib in rats demonstrated excretion of bosutinib-derived radioactivity in breast milk. A potential risk to the breast-feeding infant cannot be excluded. Breast-feeding should be discontinued during treatment with bosutinib.

Women of childbearing potential/Contraception

Women of childbearing potential should be advised to use effective contraception during treatment with bosutinib and for at least 1 month after the last dose and to avoid becoming pregnant while receiving bosutinib. In addition, the patient should be advised that vomiting or diarrhoea may reduce the efficacy of oral contraceptives by preventing full absorption.

Fertility

Based on non-clinical findings, bosutinib has the potential to impair reproductive function and fertility in humans. Men being treated with bosutinib are advised to seek advice on conservation of sperm prior to treatment because of the possibility of decreased fertility due to therapy with bosutinib.

Bosutinib has no or negligible influence on the ability to drive and use machines. However, if a patient taking bosutinib experiences dizziness, fatigue, visual impairment or other undesirable effects with a potential impact on the ability to drive or use machines safely, the patient should refrain from these activities for as long as the undesirable effects persist.

Summary of safety profile

A total of 1 372 leukaemia adult patients received at least 1 dose of single-agent bosutinib. The median duration of therapy was 26.30 months (range: 0.03 to 170.49 months). These patients were either newly-diagnosed, with CP CML or were resistant or intolerant to prior therapy with chronic, accelerated, or blast phase CML or Ph+ acute lymphoblastic leukaemia (ALL). The safety analyses included data from a completed extension study.

At least 1 adverse reaction of any toxicity grade was reported for 1,349 (98.3%) patients. The most frequent adverse reactions reported for ≥20% of patients were diarrhoea (80.4%), nausea (41.5%), abdominal pain (35.6%), thrombocytopenia (34.4%), vomiting (33.7%), rash (32.8%), ALT increased (28.0%), anaemia (27.2%), pyrexia (23.4%), AST increased (22.5%), fatigue (32.0%), and headache (20.3%). At least 1 Grade 3 or Grade 4 adverse reaction was reported for 943 (68.7%) patients. The Grade 3 or Grade 4 adverse reactions reported for ≥5% of patients were thrombocytopenia (19.7%), ALT increased (14.6%), neutropenia (10.6%), diarrhoea (10.6%), anaemia (10.3%), lipase increased (10.1%), AST increased (6.7%), and rash (5.0%).

Tabulated list of adverse reactions

These adverse reactions are presented by system organ class and frequency. Frequency categories are defined as: 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), very rare (<1/10 000), not known (cannot be estimated from the available data). Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness.

Adverse reactions for bosutinib:

^a Respiratory tract infection includes Lower respiratory tract infection, Respiratory tract infection, Respiratory tract infection viral, Upper respiratory tract infection, Viral upper respiratory tract infection
^b Influenza includes H1N1 influenza, Influenza
^c Pneumonia includes Atypical pneumonia, Pneumonia, Pneumonia bacterial, Pneumonia fungal, Pneumonia necrotising, Pneumonia streptococcal
^d Thrombocytopenia includes Platelet count decreased, Thrombocytopenia
^e Anaemia includes Anaemia, Haemoglobin decreased, Red blood cell count decreased
^f Neutropenia includes Neutropenia, Neutrophil count decreased
^g Leukopenia includes Leukopenia, White blood cell count decreased
^h Hypophosphataemia includes Blood phosphorus decreased, Hypophosphataemia
ⁱ Hyperkalaemia includes Blood potassium increased, Hyperkalaemia
^j Cardiac failure includes Cardiac failure, Cardiac failure acute, Cardiac failure chronic, Cardiac failure congestive, Cardiogenic shock, Cardiorenal syndrome, Ejection fraction decreased, Left ventricular failure
^k Cardiac ischaemic includes Acute coronary syndrome, Acute myocardial infarction, Angina pectoris, Angina unstable, Arteriosclerosis coronary artery, Coronary artery disease, Coronary artery occlusion, Coronary artery stenosis, Myocardial infarction, Myocardial ischaemia, Troponin increased
^l Hypertension includes the Blood pressure increased, Blood pressure systolic increased, Essential hypertension, Hypertension, Hypertensive crisis
^m Pulmonary hypertension includes Pulmonary arterial hypertension, Pulmonary arterial pressure increased, Pulmonary hypertension
ⁿ Acute pulmonary oedema includes Acute pulmonary oedema, Pulmonary oedema
° Abdominal pain includes Abdominal discomfort, Abdominal pain, Abdominal pain lower, Abdominal pain upper, Abdominal tenderness, Gastrointestinal pain
^p Gastrointestinal haemorrhage includes Anal haemorrhage, Gastric haemorrhage, Gastrointestinal haemorrhage, Intestinal haemorrhage, Lower gastrointestinal haemorrhage, Rectal haemorrhage, Upper gastrointestinal haemorrhage
^q Pancreatitis acute includes Pancreatitis, Pancreatitis acute
^r Hepatic function abnormal includes Hepatic enzyme increased, Hepatic function abnormal, Liver function test abnormal, Liver function test increased, Transaminases increased
^s Hepatotoxicity includes Hepatitis, Hepatitis toxic, Hepatotoxicity, Liver disorder
^t Liver injury includes Drug-induced liver injury, Hepatocellular injury, Liver injury
^u Rash includes Rash, Rash macular, Rash maculo-papular, Rash papular, Rash pruritic
^v Photosensitivity reaction includes Photosensitivity reaction, Polymorphic light eruption
^w Fatigue includes Asthenia, Fatigue, Malaise
^x Oedema includes Eyelid oedema, Face oedema, Generalised oedema, Localised oedema, Oedema, Oedema peripheral, Periorbital oedema, Periorbital swelling, Peripheral swelling, Swelling, Swelling of eyelid
^y Chest pain includes Chest discomfort, Chest pain
^z Alanine aminotransferase increased includes Alanine aminotransferase abnormal, Alanine aminotransferase increased
^aa Lipase increased includes Hyperlipasaemia, Lipase increased
^bb Amylase increased includes Amylase increased, Hyperamylasaemia
^cc Blood bilirubin increased includes Bilirubin conjugated increased, Blood bilirubin increased, Blood bilirubin unconjugated increased, Hyperbilirubinaemia
^dd Electrocardiogram QT prolonged includes Electrocardiogram QT prolonged, Long QT syndrome
^** Adverse reaction identified post marketing in adults.

Paediatric populations

A total of 55 paediatric patients ≥1 year of age received at least 1 dose of bosutinib in the Phase I/II, multicentre, international, single-arm, open-label BCHILD study. The median duration of treatment was 13.5 months (range: 0.2 to 60.9 months). These patients were either newly-diagnosed CP Ph+ CML or resistant or intolerant Ph+ CML-CP and CML-AP.

At least 1 adverse reaction of any toxicity grade was reported for 54 (98.2%) paediatric patients. The most frequent adverse reactions reported were diarrhoea (82%), abdominal pain (65%), vomiting (56%), nausea (51%), rash (36%), fatigue (35%), thrombocytopenia (35%), headache (33%), pyrexia (33%), ALT increased (29%), and decreased appetite (24%).

The most frequent Grade 3 or Grade 4 adverse reactions reported were thrombocytopenia (18%), ALT increased (15%) and diarrhoea (13%).

Blood and lymphatic system disorders

Blood and lymphatic events in 55 paediatric patients in the BCHILD study include thrombocytopenia in 19 (34.5%) patients, anaemia in 10 patients (18.2%), and neutropenia in 7 patients (12.7%). One patient discontinued treatment due to Grade 4 neutropenia. Among patients with blood and lymphatic events, 37.5% were managed with treatment interruption and 16.7% required dose reduction. Among patients with dose interruptions, none had a positive rechallenge when bosutinib was restarted. The median time to first event was 13 days (range: 1 to 757 days) and the median cumulative duration of grade ¾ events was 16.0 (range: 4 to 47) days.

Hepatobiliary disorders

Of the 55 participants, the incidence based on laboratory data of ALT and AST increased was 67.3% and 63.6%, respectively and 43 (78.2% participants experienced an increase in either ALT or AST). Most cases of transaminase elevation occurred early in treatment; of participants who experienced transaminase elevations of any grade, 83.7% experienced their first event within 3 months. The median time to onset of ALT and AST increased was 22.0 days (range: 9 to 847 days) and 18.5 days (range: 9 to 169 days), respectively. The median duration of Grade ¾ events was 18.0 days (range: 2 to 132 days) and 12 days (range: 5 to 19 days) for ALT and AST increased, respectively.

Gastrointestinal disorders

Gastrointestinal disorders of diarrhoea, vomiting and nausea occurred in 81.8%, 56.4%, and 50.9% of the 55 paediatric patients treated with bosutinib in the BCHILD study, respectively. Three (5.5%) patients discontinued bosutinib treatment due to diarrhoea (n=3), abdominal pain (n=2), nausea (n=1) and/or vomiting (n=1). Among paediatric patients with gastrointestinal disorders, 9 (19%) were managed with treatment interruption and 4 (8.3%) required dose reduction. Among the 9 patients who required a treatment interruption, 8 (88.9%) were rechallenged. Of these, 55.6% were successfully rechallenged. The median time to onset for diarrhoea was 2 days and the median duration of any grade diarrhoea was 2 days.

Renal disorders

In the paediatric study, 45 (82%) of the total 55 patients had normal eGFR (≥ 90 mL/min/1.73 m² estimated by Bedside Schwartz Equation) at baseline. Among these 45 patients, 19 (34.5%) experienced a decline in eGFR to Grade 1 (60 < 90 mL/min/1.73 m²) and 1 (1.8%) patient to Grade 2 (30 < 60 mL/min/1.73 m²) at 13.47 months. No participant had a post-baseline eGFR < 45 mL/min/1.73 m² regardless of baseline values.

Description of selected adverse reactions

Blood and lymphatic system disorders Of the 372 (27.1%) adult patients with reports of adverse reactions of anaemia, 6 patients discontinued bosutinib due to anaemia. Maximum toxicity of Grade 1 occurred in 95 (25.5%) patients, Grade 2 in 135 (36.3%) patients, Grade 3 in 113 patients (30.4%), and Grade 4 in 29 (7.8%) patients. Among these patients, the median time to first event was 29 days (range: 1 to 3 999 days) and the median duration per event was 22 days (range: 1 to 3 682 days).

Of the 209 (15.2%) adult patients with reports of adverse reactions of neutropenia, 19 patients discontinued bosutinib due to neutropenia. Maximum toxicity of Grade 1 occurred in 19 patients (9.1%), Grade 2 in 45 (21.5%) patients, Grade 3 in 95 (45.5%) patients, and Grade 4 in 50 (23.9%) patients. Among these patients, the median time to first event was 56 days (range: 1 to 1 769 days), and the median duration per event was 15 days (range: 1 to 913 days).

Of the 472 (34.4%) adult patients with reports of adverse reactions of thrombocytopenia, 42 patients discontinued bosutinib due to thrombocytopenia. Maximum toxicity of Grade 1 occurred in 114 (24.2%) patients, Grade 2 in 88 (18.6%) patients, Grade 3 in 172 (36.4%) patients, and Grade 4 in 98 (20.8%) patients. Among these patients, the median time to first event was 28 days (range: 1 to 1 688 days), and median duration per event was 15 days (range: 1 to 3 921 days).

Hepatobiliary disorders

Among adult patients with reports of adverse reactions of elevations in either ALT or AST (all grades), the median time of onset observed was 29 days with a range of onset 1 to 3 995 days for ALT 17 and AST. The median duration of an event was 17 days (range: 1 to 1 148 days), and 15 days (range: 1 to 803 days) for ALT and AST, respectively.

Two cases consistent with drug-induced liver injury (defined as concurrent elevations in ALT or AST ≥3 × ULN with total bilirubin >2 × ULN and with alkaline phosphatase <2 × ULN) without alternative causes have occurred in 2/1 711 (0.1%) adult subjects treated with bosutinib.

Hepatitis B reactivation

Hepatitis B reactivation has been reported in association with BCR-ABL TKIs. Some cases resulted in acute hepatic failure or fulminant hepatitis leading to liver transplantation or a fatal outcome.

Gastrointestinal disorders

Of the 1 103 (80.4%) patients that experienced diarrhoea, 14 patients discontinued bosutinib due to this event. Concomitant medicinal products were given to treat diarrhoea in 756 (68.5%) patients. Maximum toxicity of Grade 1 occurred in 575 (52.1%) patients, Grade 2 in 383 (34.7%) patients, Grade 3 in 144 (13.1%) patients; 1 patient (0.1%) experienced a Grade 4 event. Among patients with diarrhoea, the median time to first event was 2 days (range: 1 to 2 702 days) and the median duration of any grade of diarrhoea was 2 days (range: 1 to 4 247 days).

Among the 1 103 patients with diarrhoea, 218 patients (19.8%) were managed with treatment interruption and of these 208 (95.4%) were rechallenged with bosutinib. Of those who were rechallenged, 201 (96.6%) did not have a subsequent event or did not discontinue bosutinib due to a subsequent event of diarrhoea.

Cardiac disorders

Among 1372 patients, cardiac failure occurred in 50 (3.6%) patients and cardiac ischaemic events in 57 (4.2%) patients.

Seven patients (0.5%) experienced QTcF prolongation (greater than 500 ms). Eleven (0.8%) patients experienced QTcF increase >60 ms from baseline. Patients with uncontrolled or significant cardiovascular disease including QTc prolongation, at baseline, were not included in clinical studies.

Renal disorders

In patients with newly-diagnosed- CP CML treated with 400 mg, the median decline from baseline in eGFR (estimated by MDRD Equation) was 11.1 mL/min/1.73 m² at 1 year and 14.1 mL/min/1.73 m² at 5 years for patients on-treatment. Treatment-naïve CML patients treated with 500 mg showed a median eGFR decline of 9.2 mL/min/1.73 m² at 1 year, 12.0 mL/min/1.73 m² at 5 years and 16.6 mL/min/1.73 m² at 10 years for patients on-treatment. In pre-treated patients with CP and advanced stage CML treated with 500 mg the median eGFR decline was 7.6 mL/min/1.73 m² at 1 year, 12.3 mL/min/1.73 m² at 5 years and 15.9 mL/min/1.73 m² at 10 years for patients on-treatment. In patients with Ph+ CML previously treated with 1 or more TKI(s) treated with 500 mg, the median eGFR decline from baseline was 9.2 mL/min/1.73 m² at 1 year and 14.5 mL/min/1.73 m² at 4 years for patients on-treatment.