Clinical Pharmacology for Truseltiq
Mechanism Of Action
Infigratinib is a small molecule kinase inhibitor of FGFR with IC50 values of 1.1, 1, 2, and 61 nM for FGFR1, FGFR2, FGFR3, and FGFR4, respectively. The major human metabolites of infigratinib, BHS697 and CQM157, have similar in vitro binding affinities for FGFR1, FGFR2, and FGFR3 compared to infigratinib. Infigratinib inhibited FGFR signaling and decreased cell proliferation in cancer cell lines with activating FGFR amplifications, mutations, or fusions. Constitutive FGFR signaling can support the proliferation and survival of malignant cells. Infigratinib had anti-tumor activity in mouse and rat xenograft models of human tumors with activating FGFR2 or FGFR3 alterations, including two patient-derived xenograft models of cholangiocarcinoma that expressed FGFR2-TTC28 or FGFR2-TRA2B fusions. Infigratinib demonstrated brain-to-plasma concentration ratios (based on AUC0-inf) of 0.682 in rats after a single oral dose.
Pharmacodynamics
Serum Phosphate
TRUSELTIQ increased serum phosphate levels due to FGFR inhibition. Serum phosphate increased with increasing exposures across the dose range of 20 to 150 mg once daily (0.16 to 1.2 times the approved recommended dosage), with increased risk of hyperphosphatemia with higher exposure to TRUSELTIQ.
Cardiac Electrophysiology
At the recommended dosing regimen, TRUSELTIQ does not result in a large mean increase (i.e., >20 msec) in the QTc interval. The QT effect of infigratinib at higher exposures associated with CYP3A inhibition has not been studied.
Pharmacokinetics
The infigratinib pharmacokinetic parameters are presented following administration of the approved recommended dosage in cholangiocarcinoma patients, unless otherwise specified.
The mean (coefficient of variation [%CV]) steady-state maximum plasma concentration (Cmax) and area under the curve over a dosing interval (AUC0-24h) of infigratinib and active metabolites, BHS697 and CQM157, are presented in Table 5.
Table 5: Mean (%CV) Exposure of Infigratinib and Active Metabolites
|
Infigratinib |
BHS697 |
CQM157 |
| Cmax |
282.5 ng/mL (54%) |
42.1 ng/mL (65%) |
15.7 ng/mL (92%) |
| AUC0-24h |
3780 ng•h/mL (59%) |
717 ng•h/mL (55%) |
428 ng•h/mL (72%) |
Infigratinib Cmax and AUC increased more than proportionally across the dose range of 5 to 150 mg (0.04 to 1.2 times the approved recommended dose). Steady state was achieved within 15 days and the mean accumulation ratio was 8- and 5-fold for Cmax and AUC, respectively.
Absorption
Median (range) time to achieve peak infigratinib plasma concentration (tmax) was 6 hours (2 to 7 hours) at steady state.
Effect Of Food
Following administration of TRUSELTIQ with a high-fat and high-calorie meal (800 to 1,000 calories with approximately 50% of total caloric content of the meal from fat) in healthy subjects, the mean AUCinf of infigratinib increased by 80%-120% and Cmax increased by 60%-80%, the median Tmax shifted from 4 hours to 6 hours. Following administration of TRUSELTIQ with a low-fat low-calorie meal (approximately 330 calories with 20% of total caloric content of the meal from fat), the mean AUCinf of infigratinib increased by 70%, Cmax increased by 90%, and the median Tmax did not change.
Distribution
The geometric mean (CV%) apparent volume of distribution of infigratinib was 1600 L (33%) at steady state. The mean infigratinib protein binding was 96.8%, primarily to lipoprotein, and was dependent of drug concentration.
Elimination
The geometric mean (CV%) total apparent clearance (CL/F) of infigratinib was 33.1 L/h (59%) at steady state. The geometric mean (CV%) terminal half-life of infigratinib was 33.5 h (39%) at steady state.
Metabolism
Infigratinib is predominantly metabolized by CYP3A4 (~94%) and to a lesser extent by FMO3 (6%) in vitro. The major drug-related moiety in plasma was unchanged infigratinib (38% of dose) in a human [14C] mass balance study, followed by two active metabolites, BHS697 and CQM157 (each at >10% of dose). BHS697 is mainly metabolized by CYP3A4 and CQM157 is metabolized through both Phase I and Phase II biotransformation pathways.
BHS697 and CQM157 contribute about 16% to 33% and 9% to 12% of overall pharmacologic activity, respectively.
Excretion
After a single oral 125 mg dose of radiolabeled infigratinib in healthy subjects, approximately 77% of the dose was recovered in feces (3.4% as unchanged) and 7.2% in urine (1.9% as unchanged).
Specific Populations
No clinically significant differences in the systemic exposure of infigratinib were observed based on age (19-86 years), sex, race/ethnicity (White 70.7%, Black 15.4%, and Asian 8%), or body weight (36.4-169 kg).
Patients With Renal Impairment
The relative potency adjusted steady state AUC of infigratinib plus its active metabolites (BHS697, CQM157) in plasma increased by 32% and 37% in patients with mild (creatinine clearance [CLcr] 60 to 89 mL/min estimated by Cockcroft-Gault) and moderate renal impairment (CLcr 30 to 59 mL/min), respectively, relative to patients with normal renal function (CLcr ≥ 90 mL/min).
The effect of severe renal impairment (CLcr < 30 mL/min) or renal dialysis in end-stage renal disease on infigratinib exposure is unknown.
Patients With Hepatic Impairment
The relative potency adjusted steady state AUC of infigratinib plus its active metabolites (BHS697, CQM157) in plasma increased by 47%-62% and 99% in patients with mild (total bilirubin > upper limit of normal [ULN] to 1.5 × ULN or AST > ULN) and moderate hepatic impairment (total bilirubin > 1.5 to 3 × ULN with any AST), respectively, relative to patients with normal hepatic function (total bilirubin ≤ ULN and AST ≤ ULN).
The effect of severe hepatic impairment (total bilirubin > 3 × ULN with any AST) on infigratinib exposure is unknown [see Use In Specific Populations].
Drug Interaction Studies
Clinical Studies
Strong CYP3A Inhibitors
Coadministration of multiple doses of itraconazole (strong CYP3A inhibitor) increased infigratinib AUC0-inf by 622% and Cmax by 164%, increased BHS697 AUC0-inf by 174%, and decreased CQM157 Cmax by 69%, respectively [see DRUG INTERACTIONS].
Strong CYP3A Inducers
Coadministration of multiple doses of rifampin (strong CYP3A inducer) decreased infigratinib AUC0-inf by 56% and Cmax by 44%, decreased BHS697 AUC0-inf by 65% and Cmax by 27%, and decreased CQM157 AUC0-inf by 76% and Cmax by 50%, respectively [see DRUG INTERACTIONS].
Gastric Acid-Lowering Agents
Coadministration of multiple doses of lansoprazole (proton pump inhibitor) decreased infigratinib AUC0-inf by 45% and Cmax by 49%, decreased BHS697 AUC0-inf by 32% and Cmax by 44%, and decreased CQM157 AUC0-inf by 72% and Cmax by 55%, respectively [see DRUG INTERACTIONS].
CYP3A4 Substrates
No clinically significant differences in pharmacokinetics of midazolam (sensitive CYP3A4 substrate) were observed when co-administered with TRUSELTIQ [see DRUG INTERACTIONS].
In Vitro Studies
Cytochrome P450 Enzymes
Infigratinib does not induce CYP1A2, CYP2B6, CYP2C9, or CYP3A4. Infigratinib, BHS697, and CQM157 do not inhibit major CYP450 isozymes at clinically relevant concentrations.
Transporter Systems
Infigratinib inhibits MATE1 and BCRP. Infigratinib has a low potential to inhibit P-gp, BSEP, OCT1, OCT2 and MATE-2K at clinically relevant concentrations. Infigratinib is a substrate for P-gp and BCRP. The metabolites BHS697 and CQM157 have a low potential to inhibit OATP1B1, OATP1B3, P-gp, or BCRP at clinically relevant concentrations. The effect of these metabolites to inhibit MATE or OCT at clinically relevant concentrations is unknown.
Clinical Studies
Cholangiocarcinoma
Study CBGJ398X2204 (NCT02150967), a multicenter open-label single-arm trial, evaluated the efficacy of TRUSELTIQ in 108 patients with previously treated, unresectable locally advanced or metastatic cholangiocarcinoma with an FGFR2 fusion or rearrangement as determined for enrollment by local (89%) or central testing (11%). Qualifying in-frame fusions and other rearrangements were predicted to have a breakpoint within intron 17/exon 18 of the FGFR2 gene that leaves the FGFR2 kinase domain intact.
Patients received TRUSELTIQ at a dosage of 125 mg orally once daily for 21 consecutive days followed by 7 days off therapy, in 28-day cycles until disease progression or unacceptable toxicity. The major efficacy outcome measures were overall response rate (ORR) and duration of response (DoR), as determined by blinded independent central review (BICR) according to Response Evaluation Criteria in Solid Tumors (RECIST) v1.1.
The median age was 53 years (range: 23 to 81 years), 62% were female, 72% were White, 3.7% were Black or African American, 10% were Asian, and 99% had a baseline Eastern Cooperative Oncology Group (ECOG) performance status of 0 (42%) or 1 (57%). The presence of FGFR2 fusions or other rearrangements was determined in 104 enrolled patients (96%) with Next Generation Sequencing (NGS) testing. Eighty-eight (81%) patients had in-frame FGFR2 fusions, and BICC1 the most commonly reported fusion partner (n=27, 25%). Twenty (19%) patients had other FGFR2 rearrangements that may not be in-frame with the partner gene or the partner gene was not identifiable.
Ninety-nine percent of patients had metastatic (Stage IV) disease at the time of study entry. All patients had received at least 1 prior line of systemic therapy, 32% had 2 prior lines of therapy, and 29% had 3 or more prior lines of therapy. Ninety-nine percent of patients received prior gemcitabine-based therapy and most (88%) had progressed on their prior gemcitabine-based therapy.
Efficacy results are summarized in Table 6. The median time to response was 3.6 months (range 1.4 – 7.4 months).
Table 6: Efficacy Results in Study CBGJ398X2204
| Efficacy Parameter |
TRUSELTIQ
N=108 BICR Assessment |
| ORR (95% CI) |
23% (16, 32) |
| Complete Response, n (%) |
1 (1%) |
| Partial Response, n (%) |
24 (22%) |
| Median DoR (months) (95% CI) |
5.0 (3.7, 9.3) |
| Patients with DoR ≥6 months, n (%) |
8 (32%) |
| Patients with DoR ≥12 months, n (%) |
1 (4%) |
Abbreviations: BICR= blinded independent central review; CI=confidence interval; DoR=duration of response; ORR=overall response rate.
Note: Data are according to RECIST v1.1. |