The objective is to determine whether the test product, Methotrexate 40 mg/mL solution for injection administered subcutaneously by the prefilled and needle-free delivery system Zeneo®, and the reference product, Methotrexate Biodim® 25 mg/mL, solution for injection administered subcutaneously by a conventional syringe with needle are bioequivalent.

ABSTRACT Objective: Zeneo1 is a needle-free injection device. We performed a pharmacokinetic study to investigate the bioequivalence of methotrexate administered subcutaneously using either the needle-free injection device or a conventional needle and syringe.

Research design and methods: This was a single-dose, open-label, laboratory-blind, randomized crossover study performed in adult healthy volunteers. Each participant received two methotrexate injections (each 25mg), one via needle-free injection device and one via conventional injection, with a 21-28 day wash-out interval between dosing. For each participant, the administration site for both injections was either the abdomen or the thigh.

Main outcome measures: The primary pharmacokinetic outcome parameters were AUC(0-t) and Cmax.

Bioequivalence was assessed by standard criteria: whether 90% confidence intervals of geometric mean ratios for the two administration methods were within 80-125%.

Results: Fifty-two individuals completed the study. Bioequivalence criteria were met for AUC(0-t), for the overall analysis (both injection sites: 90% confidence interval: 99.4-103.1%), and for each injection site separately. Bioequivalence was similarly demonstrated with AUC(0-1). Bioequivalence criteria for Cmax were fulfilled for abdominal administration but not for the overall analysis. Injection via the needle- free injection device was well tolerated.

Limitations: Limitations include conducting the study in healthy volunteers and the relatively small subject number (albeit satisfactory for bioequivalence).

Conclusions: This study shows that methotrexate injection via needle-free injection device is bioequivalent to a conventional needle and syringe in relation to AUC(0-t) and AUC(0-1). Studies of needle-free injection device use in patients requiring methotrexate therapy are planned.

Inclusion Criteria:

• Healthy subjects
• BMI between 18.5 and 30 kg/m2
• Body mass > 60 kg
• Non-tobacco user
• Written consent given for participation in the study

Exclusion Criteria:

• Evidence of clinically relevant oral, cardiovascular, hematologic, gastrointestinal, hepatic, renal, endocrine, pulmonary, neurologic, psychiatric or skin disorder
• Heavy alcohol consumption and regular exposure to drug of abuse