Systemic pharmacokinetics and cerebrospinal fluid uptake of intravenous ceftriaxone in patients with amyotrophic lateral sclerosis.

The cephalosporin antibiotic ceftriaxone was evaluated as a potential therapeutic agent for the treatment of amyotrophic lateral sclerosis (ALS). The pharmacokinetics (PK) of ceftriaxone in plasma and cerebrospinal fluid (CSF) were investigated in 66 participants in a previously reported clinical trial. Their mean age was 51 years, and 65 % were male. Participants were randomly assigned to one of three treatment groups receiving intravenous infusions (mean duration: 25 minutes) every 12 hours of either: placebo and placebo; 2 grams ceftriaxone and placebo; or 2 grams ceftriaxone twice. Mean steady-state plasma PK variables were: volume of distribution, 14 liters (0.17 liters/kg); elimination half-life, 8 - 9 hours; total clearance, 17-21 mL/min (0.22 - 0.25 mL/min/kg). Values were not different between dosage groups. CSF PK analysis, determined through sparse CSF sampling, indicated apparent entry and elimination half-life values of 1.0 and 34 hours, respectively. With both dosage regimens, CSF concentrations were maintained above the target threshold of 1.0 μM (0.55 μg/mL) as determined from in vitro models. The plasma and CSF PK profile of ceftriaxone were used as a basis for planning the Phase 3 clinical trial of ceftriaxone in ALS.