Infigratinib

Uses

Infigratinib is an FGFR inhibitor used to treat locally advanced or metastatic cholangiocarcinoma in adults with a fibroblast growth factor receptor 2 (FGFR2) rearrangement.

Infigratinib is indicated for the treatment of previously treated, unresectable locally advanced or metastatic cholangiocarcinoma in adults with a fibroblast growth factor receptor 2 (FGFR2) fusion or another rearrangement as detected by an FDA-approved test.

Infigratinib is also used to associated treatment for these conditions: Unresectable, locally advanced Cholangiocarcinomas, Unresectable, metastatic Cholangiocarcinomas

How Infigratinib works

Fibroblast growth factor receptors (FGFRs) are tyrosine kinase receptors that play a role in cell proliferation, differentiation, migration, survival, and angiogenesis. Upon binding of extracellular signals, primarily fibroblast growth factors, FGFR dimerizes to promote phosphorylation of downstream molecules and activation of the Ras-mitogen-activated protein kinase (MAPK) pathway. In some cancers, the FGFR signalling pathway is aberrant and disrupted, leading to unregulated cell proliferation and growth, including malignant cells. Alterations in the FGFR receptors, including mutations, amplifications, and fusions, are associated with a wide array of neoplasms, including prostate, urothelial, ovarian, breast, and liver cancer. In particular, FGFR2 fusion is closely related to intrahepatic cholangiocarcinoma: recent studies show that up to 45% of patients with intrahepatic cholangiocarcinoma exhibited gene rearrangements resulting in FGFR2 fusion proteins. Alterations in FGFR in tumours can lead to constitutive FGFR signalling, supporting the proliferation and survival of malignant cells. Infigratinib is a reversible, non-competitive inhibitor of all four FGFR subtypes - FGFR1, FGFR2, FGFR3, and FGFR4 - that blocks FGFR signalling and inhibits cell proliferation in cancer cell lines with activating FGFR amplification, mutations, or fusions. Out of the four FGFR subtypes, infigratinib has the highest affinity for FGFR1, FGFR2, and FGFR3. Infigratinib binds to the allosteric site between the two kinase lobes of the FGFR - or more specifically, to the ATP-binding cleft. Binding to this cleft prevents autophosphorylation of the receptor and blocks downstream signalling cascades that would otherwise activate MAPK.

Toxicity

There is limited information on lethal doses and overdose of infigratinib. In clinical trials, infigratinib was associated with ocular toxicity (retinal pigment epithelial detachment), hyperphosphatemia leading to soft tissue mineralization, and embryo-fetal toxicity.

Food Interaction

• Take on an empty stomach. Take drug at least 1 hour before or 2 hours after food, at approximately the same time each day. Food increases the systemic exposure to infigratinib.
• Take with a full glass of water. Do not crush, chew or dissolve.

[Major] ADJUST DOSING INTERVAL: Food may increase the oral bioavailability of infigratinib.

Coadministration with a high-fat, high-calorie meal (800 to 1,000 calories, with approximately 50% of total calories from fat) in healthy subjects increased mean infigratinib peak plasma concentration (Cmax) and total systemic exposure (AUC) by 60% to 80% and 80% to 120%, respectively, and increased the median time to Cmax from 4 hours to 6 hours.

When coadministered with a low-fat, low-calorie meal (approximately 330 calories, with 20% of total calories from fat), mean infigratinib Cmax and AUC increased by 90% and 70%, respectively, while the median time to Cmax did not change.

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of infigratinib and one of its active metabolites, BHS697, both of which are primarily metabolized by CYP450 3A4 in vitro.

The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit.

Inhibition of hepatic CYP450 3A4 may also contribute.

The interaction has not been studied with grapefruit juice but has been reported for other CYP450 3A4 inhibitors.

Coadministration of infigratinib with multiple doses of itraconazole, a potent CYP450 3A4 inhibitor, increased infigratinib peak plasma concentration (Cmax) and total systemic exposure (AUC) by 164% and 622%, respectively, and the AUC for the active metabolite, BHS697, by 174%.

In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands.

Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition.

Increased exposure to infigratinib and BHS697 may increase the incidence and severity of serious adverse reactions such as infections, anemia, pyrexia, abdominal pain, hypercalcemia, hyperphosphatemia, ocular toxicity (e.g., retinal pigment epithelial detachment), sepsis, stomatitis, diarrhea, palmar-plantar erythrodysesthesia syndrome, increased blood creatinine, increased lipase, and onycholysis.

MANAGEMENT: Infigratinib should be administered on an empty stomach at least one hour before or two hours after food.

Patients should avoid consumption of grapefruit, grapefruit juice, or supplements that contain grapefruit during treatment with infigratinib.

Infigratinib Disease Interaction

Moderate: liver impairment, phosphate imbalance, renal impairment, retinal disorder

Volume of Distribution

At steady state, the geometric mean (CV%) apparent volume of distribution of infigratinib was 1600 L (33%). In rats receiving a single oral dose, infigratinib had brain-to-plasma concentration ratios (based on AUC_0-inf) of 0.682.

Elimination Route

Mean (%CV) C_max is 282.5 ng/mL (54%) and AUC_0-24h is 3780 ngxh/mL (59%) for infigratinib. Infigratinib C_max and AUC increase more than proportionally across the dose range of 5 to 150 mg and steady state is achieved within 15 days. At steady state, median time to achieve peak infigratinib plasma concentration (T_max) is six hours, with a range between two and seven hours.

Mean (%CV) C_max is 42.1 ng/mL (65%) for BHS697 and 15.7 ng/mL (92%) for CQM157. Mean (%CV) AUC_0-24h is 717 ngxh/mL (55%) for BHS697 and 428 ngxh/mL (72%) for CQM157. In healthy subjects, a high-fat and high-calorie meal increased AUCinf of infigratinib by 80%-120% and C_max by 60%-80%. The median T_max also shifted from four hours to six hours. A low-fat low-calorie meal increased the mean AUC_inf of infigratinib by 70% and C_max by 90%/

Half Life

The geometric mean (CV%) terminal half-life of infigratinib was 33.5 h (39%) at steady state.

Clearance

The geometric mean (CV%) total apparent clearance (CL/F) of infigratinib was 33.1 L/h (59%) at steady state.

Elimination Route

Following administration of a single oral dose of radiolabeled infigratinib in healthy subjects, approximately 77% of the dose was recovered in feces, where 3.4% of the dose was in the unchanged parent form. About 7.2% was recovered in urine with 1.9% of the dose was unchanged.

Innovators Monograph

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