Quizartinib

Co-administration of quizartinib with other medicinal products that prolong the QT interval may further increase the incidence of QT prolongation. Examples of QT prolonging medicinal products include but are not limited to antifungal azoles, ondansetron, granisetron, azithromycin, pentamidine, doxycycline, moxifloxacin, atovaquone, prochlorperazine and tacrolimus. Caution should be used when co-administering medicinal products that prolong the QT interval with quizartinib.

Quizartinib is associated with QT interval prolongation. QT interval prolongation may increase the risk of ventricular arrhythmias or torsade de pointes. Patients with congenital long QT syndrome and/or a previous history of torsade de pointes were excluded from the quizartinib development programme. Quizartinib must not be used in patients with congenital long QT syndrome.

Quizartinib should be used with caution in patients who are at significant risk of developing QT interval prolongation. These include patients with uncontrolled or significant cardiovascular disease (e.g., history of second-or third-degree heart block (without pacemaker), myocardial infarction within 6 months, uncontrolled angina pectoris, uncontrolled hypertension, congestive heart failure, history of clinically relevant ventricular arrhythmias or torsade de pointes), and patients receiving concomitant medicinal products known to prolong the QT interval. Electrolytes should be maintained in the normal range.

Do not start treatment with quizartinib if the QTcF interval is greater than 450 ms.

During induction and consolidation, ECGs should be performed prior to initiation and then once weekly during quizartinib treatment or more frequently as clinically indicated.

During maintenance, ECGs should be performed prior to initiation and then once weekly for the first month following dose initiation and escalation, and thereafter as clinically indicated. The maintenance starting dose should not be escalated if the QTcF interval is greater than 450 ms.

Permanently discontinue quizartinib in patients who develop QT interval prolongation with signs or symptoms of life-threatening arrhythmia.

ECG monitoring of the QT interval should be performed more frequently in patients who are at significant risk of developing QT interval prolongation and torsade de pointes.

Monitoring and correction of hypokalaemia and hypomagnesaemia should be performed prior to and during treatment with quizartinib. More frequent monitoring of electrolytes and ECGs should be performed in patients who experience diarrhoea or vomiting.

Co-administration of ketoconazole (200 mg twice daily for 28 days), a strong CYP3A/P-gp inhibitor, with a single dose of quizartinib increased quizartinib maximum plasma concentration (C_max) and area under the curve (AUC_inf) by 1.17-fold and 1.94-fold, respectively, and decreased AC886 C_max and AUC_inf by 2.5-fold and 1.18-fold, respectively, compared to quizartinib alone. At steady state, quizartinib exposure (C_max and AUC_0-24h) was estimated to be increased by 1.86-fold and 1.96-fold, respectively, and AC886 exposure (C_max and AUC_0-24h) decreased by 1.22-fold and 1.17-fold, respectively. Increased quizartinib exposure may increase the risk of toxicity.

The dose of quizartinib should be reduced as shown in the table below if concomitant use with strong CYP3A inhibitors cannot be avoided.

Examples of strong CYP3A/P-gp inhibitors include itraconazole, posaconazole, voriconazole, clarithromycin, nefazodone, telithromycin and antiretroviral medicinal products (Certain medicines used to treat HIV may either increase the risk of side effects (e.g., ritonavir) or reduce the effectiveness (e.g., efavirenz or etravirine) of quizartinib).

Co-administration of efavirenz (lead-in treatment at 600 mg once daily for 14 days), a moderate CYP3A inducer, with a single dose of quizartinib decreased quizartinib C_max and AUC_inf by approximately 1.18-fold and 9.7-fold, respectively, compared to quizartinib alone. The C_max and AUC_inf of AC886 decreased by approximately 3.1-fold and 26-fold, respectively.

Decreased quizartinib exposure may lead to reduced efficacy. Co-administration of quizartinib with strong or moderate CYP3A inducers should be avoided.

Examples of strong CYP3A4 inducers include apalutamide, carbamazepine, enzalutamide, mitotane, phenytoin, rifampicin and certain herbal medicinal products such as St. John’s Wort (also known as Hypericum perforatum). Examples of moderate CYP3A4 inducers include efavirenz, bosentan, etravirine, phenobarbital and primidone.

Quizartinib is not recommended for use in patients with severe renal impairment (CLcr <30 mL/min, estimated by Cockcroft-Gault), as safety and efficacy have not been established in this population.

Quizartinib is not recommended for use in patients with severe hepatic impairment (Child-Pugh Class C), as safety and efficacy have not been established in this population.

There are no human data on the effect of quizartinib on fertility. Based on findings in animals, female and male fertility may be impaired during treatment with quizartinib.

There are no data on the use of quizartinib in pregnant women. Based on findings in animals, quizartinib may cause embryo-foetal toxicity when administered to pregnant women.

Quizartinib should not be used during pregnancy and in women of childbearing potential not using contraception, unless the clinical condition of the woman requires treatment. Pregnant women should be advised of the potential risk to the foetus.

It is unknown whether quizartinib or its active metabolites are excreted in human milk. A risk to breast-fed children cannot be excluded. Because of the potential for serious adverse reactions in breast-fed children, women must not breast-feed during treatment with quizartinib and for at least 5 weeks after the last dose.

Women of childbearing potential / Contraception in males and females

Women of childbearing potential should undergo pregnancy testing within 7 days before starting treatment with quizartinib.

Quizartinib may cause embryo-foetal harm when administered to pregnant women; therefore, women of childbearing potential should use effective contraception during treatment with quizartinib and for at least 7 months after the last dose.

Male patients with female partners of childbearing potential should use effective contraception during treatment with quizartinib and for at least 4 months after the last dose.

Fertility

There are no human data on the effect of quizartinib on fertility. Based on findings in animals, female and male fertility may be impaired during treatment with quizartinib.

Quizartinib has no or negligible influence on the ability to drive and use machines.

Summary of the safety profile

The most common adverse reactions were increased alanine aminotransferase (58.9%), decreased platelet count (40.0%), decreased haemoglobin (37.4%), diarrhoea (37.0%), nausea (34.0%), abdominal pain (29.4%), headache (27.5%), vomiting (24.5%) and decreased neutrophil count (21.9%).

The most common Grade 3 or 4 adverse reactions were decreased platelet count (40%), decreased haemoglobin (35.5%), decreased neutrophil count (21.5%), increased alanine aminotransferase (12.1%), bacteraemia (7.2%) and fungal infections (5.7%). The most common serious adverse reactions in the quizartinib arm were neutropenia (3.0%), fungal infections (2.3%) and herpes infections (2.3%). Adverse reactions with fatal outcome were fungal infections (0.8%) and cardiac arrest (0.4%).

The most common adverse reactions associated with dose interruption of quizartinib were neutropenia (10.6%), thrombocytopenia (4.5%) and prolonged electrocardiogram QT interval (2.6%).

The most common adverse reactions associated with dose reduction were neutropenia (9.1%), thrombocytopenia (4.5%) and prolonged electrocardiogram QT interval (3.8%).

The most common adverse reaction associated with permanent discontinuation of quizartinib was thrombocytopenia (1.1%).

Tabulated list of adverse reactions

The safety of quizartinib was investigated in QuANTUM-First, a randomised, double-blind, placebo-controlled study in adult patients with newly diagnosed FLT3-ITD positive AML.

Adverse reactions are listed according to MedDRA System Organ Class (SOC). Within each SOC, the adverse reactions are ranked by frequency with the most frequent reactions first, using the following convention: 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 category, adverse reactions are presented in order of decreasing seriousness.

Adverse reactions:

Standard chemotherapy = cytarabine (cytosine arabinoside) and anthracycline (daunorubicin or idarubicin).
^a Upper respiratory tract infections include upper respiratory tract infection, nasopharyngitis, sinusitis, rhinitis, tonsillitis, laryngopharyngitis, pharyngitis bacterial, pharyngotonsillitis, viral pharyngitis and acute sinusitis.
^b Fungal infections include oral candidiasis, bronchopulmonary aspergillosis, fungal infection, vulvovaginal candidiasis, aspergillus infection, lower respiratory tract infection fungal, oral fungal infection, candida infection, fungal skin infection, mucormycosis, oropharyngeal candidiasis, aspergillosis oral, hepatic infection fungal, hepatosplenic candidiasis, onychomycosis, fungemia, systemic candida and systemic mycosis.
^c Herpes infections include oral herpes, herpes zoster, herpes virus infections, herpes simplex, human herpesvirus 6 infection, genital herpes and herpes dermatitis.
^d Bacteraemia includes bacteraemia, Klebsiella bacteraemia, Staphylococcal bacteraemia, Enterococcal bacteraemia, Streptococcal bacteraemia, device-related bacteraemia, Escherichia bacteraemia, Corynebacterium bacteraemia and Pseudomonal bacteraemia.
^e Terms based on laboratory data.
^f Headache includes headache, tension headache and migraine.
^g One subject experienced two events (ventricular fibrillation and cardiac arrest).
^h Diarrhoea includes diarrhoea and diarrhoea haemorrhagic.
ⁱ Abdominal pain includes abdominal pain, abdominal pain upper, abdominal discomfort, abdominal pain lower and gastrointestinal pain.
^j Oedema includes oedema peripheral, face oedema, oedema, fluid overload, generalised oedema, peripheral swelling, localised oedema and face swelling.
^k Electrocardiogram QT prolonged includes electrocardiogram QT prolonged and electrocardiogram QT interval abnormal.

Description of selected adverse reactions

Cardiac disorders

Quizartinib prolongs the QT interval on ECG. Any grade QT interval prolongation treatment-emergent adverse reactions were reported in 14.0% of quizartinib-treated patients and 3.0% of patients experienced reactions of Grade 3 or higher severity. QT prolongation was associated with dose reduction in 10 (3.8%) patients, dose interruption in 7 (2.6%) patients, and discontinuation in 2 (0.8%) patients. QTcF >500 ms occurred in 2.3% of patients based on central review of ECG data. Two (0.8%) patients treated with quizartinib experienced cardiac arrest with recorded ventricular fibrillation, one with a fatal outcome, both in the setting of severe hypokalaemia. Electrocardiograms, monitoring and correction of hypokalaemia and hypomagnesemia should be performed prior to and during treatment with quizartinib.

Other special populations

Elderly

Fatal infections have occurred more frequently with quizartinib in elderly patients (i.e., older than 65 years), compared to younger patients (13% vs. 5.7%), especially in the early treatment period.

Patients older than 65 years of age should be closely monitored for the occurrence of severe infections during induction.