Not reported in the public reviews. Reviewers summarise selectively, so this usually means it wasn't discussed publicly, not that it wasn't studied.
Biodistribution & persistence
Low brain, lens and bone levels in rat QWBA; relebactam not prone to cross the blood-brain barrier
“Brain, seminal vesicles, eye lens and bone were among the tissues with lowest concentrations of radioactivity (<1.5 μg equiv/g at Tmax). The low levels of radioactivity in the brain suggests REL is not prone to pass the blood brain barrier.”
CNS toxicity (rat) and renal toxicity (monkey), possibly additive with imipenem
“Because nonclinical studies with relebactam revealed a potential for CNS toxicity in rats and renal toxicity in monkeys, it may be important to determine if an additive or synergisticpotential for these toxicities can occur when imipenem/cilastatin are clinically administered concomitantly with relebactam.”
✓ VerifiedFDA multi-discipline review, p. 40Source ↗