th the following laboratory values were excluded from the pralatrexate lymphoma clinical trials: total bilirubin >1.5mg/dL; aspartate aminotransferase (AST) or alanine aminotransferase (ALT) > 2.5 × upper limit of normal (ULN); and AST or ALT > 5 × ULN if documented hepatic involvement with lymphoma.
8.7 Renal Impairment
[see Warnings and Precautions (5.7) and Clinical Pharmacology (12.3)].
10 OVERDOSAGE
No specific information is available on the treatment of overdosage of FOLOTYN. If an overdose occurs, general supportive measures should be instituted as deemed necessary by the treating physician. Based on FOLOTYN'S mechanism of action the prompt administration of leucovorin should be considered.
11 DESCRIPTION
FOLOTYN (pralatrexate injection) contains pralatrexate, which is an antineoplastic folate analog. Pralatrexate has the chemical name (2S)-2-[[4-[(1RS)-1-[(2, 4-diaminopteridin-6-yl)methyl]but-3-ynyl]benzoyl]amino]pentanedioic acid. The structural formula is as follows:
Pralatrexate is a 1:1 racemic mixture of S- and R- diastereomers at the C10 position (indicated with *).
The molecular formula is C23H23N7O5 and the molecular weight is 477.48 g/mol.
Pralatrexate is an off-white to yellow solid. It is soluble in aqueous solutions at pH 6.5 or higher. Pralatrexate is practically insoluble in chloroform and ethanol. The pKa values are 3.25, 4.76, and 6.17.
FOLOTYN is supplied as a preservative-free, sterile, isotonic, non-pyrogenic clear yellow aqueous parenteral solution contained in a single-use clear glass vial (Type I) for intravenous administration. Each 1 mL of solution contains 20 mg of pralatrexate, sufficient sodium chloride to achieve an isotonic (280-300mOsm) solution, and sufficient sodium hydroxide, and hydrochloric acid if needed, to adjust and maintain the pH at 7.5-8.5. FOLOTYN is supplied as either 20 mg (1 mL) or 40 mg (2 mL) single-use vials at a concentration of 20 mg/mL.
12 CLINICAL PHARMACOLOGY
12.1 Mechanism of Action
Pralatrexate is a folate analog metabolic inhibitor that competitively inhibits dihydrofolate reductase. It is also a competitive inhibitor for polyglutamylation by the enzyme folylpolyglutamyl synthetase. This inhibition results in the depletion of thymidine and other biological molecules the synthesis of which depends on single carbon transfer.
12.3 Pharmacokinetics
Absorption
The pharmacokinetics of pralatrexate administered as a single agent at a dose of 30 mg/m2 administered as an intravenous push over 3-5 minutes once weekly for 6 weeks in 7-week cycles have been eva luated in 10 patients with PTCL. The total systemic clearance of pralatrexate diastereomers was 417mL/min (S-diastereomer) and 191 mL/min (R-diastereomer). The terminal elimination half-life of pralatrexate was 12-18 hours (coefficient of variance [CV] = 62-120%). Pralatrexate total systemic exposure (AUC) and maximum plasma concentration (Cmax) increased proportionally with dose (dose range 30-325 mg/m2, including pharmacokinetics data from high-dose solid tumor clinical studies). The pharmacokinetics of pralatrexate did not change significantly over multiple treatment cycles, and no accumulation of pralatrexate was observed.
Distribution
Pralatrexate diastereomers showed a steady-state volume of distribution of 105 L (S-diastereomer) and 37 L (R-diastereomer). In vitro studies indicated tha
