GenotoxicityAcceptedBeyond the letter
Positive in vitro clastogenicity for sulopenem etzadroxil and sulopenem; judged non-genotoxic on negative in vivo micronucleus and Ames results
Why: Negative in vitro mutagenicity and in vivo micronucleus assays · Weight of evidence
“Based on the negative results in the in vitro mutagenicity assays and the in vivo micronucleus assays, the weight of evidence supports a negative potential for genotoxicity for sulopenem etzadroxil.”
✓ VerifiedFDA integrated review, p. 261Source ↗ Impurity or metaboliteAcceptedBeyond the letter
Formaldehyde released on prodrug hydrolysis not measurable in toxicology studies because of a high quantitation limit
Why: Formaldehyde formed is much smaller than the normal body burden · Pharmacology or kinetics
“However, measurable quantities of formaldehyde were not observed in any of the rat or monkey toxicology studies, although the lower limit of quantitation for formaldehyde in these studies was high, µg/ml.”
✓ VerifiedFDA integrated review, p. 261Source ↗ “Because the amount of formaldehyde formed through hydrolysis of sulopenem etzadroxil is expected to be much smaller than the normal body burden, the formation of formaldehyde is not a safety concern.”
✓ VerifiedFDA integrated review, p. 261Source ↗ Efficacy modelCriticised but acceptedBeyond the letter
Murine thigh infection model PK/PD targets deemed unreliable because of study design deficiencies
Why: In vitro target attainment and hollow-fiber model results supportive · Other reason
“Due to deficiencies in the murine thigh infection model study design and limited interpretability of the findings, the resulting targets (i.e., 16.6 and 20.3% fT>MIC for stasis and 1-log kill, respectively) were deemed unreliable.”
✓ VerifiedFDA integrated review, p. 45Source ↗ “Despite the limitations of nonclinical PK/PD data (see Section 5.1), the results of PTA analyses and a 5-day in vitro hollow-fiber infection model study are supportive of the effectiveness of 500 mg sulopenem etzadroxil/500 mg probenecid BID in the treatment of uUTI.”
✓ VerifiedFDA integrated review, p. 45Source ↗ Safety marginVerdict not stated
Rabbit maternal toxicity and reduced fetal weights at about 0.1 and 0.2 times clinical sulopenem exposure
“In rabbits, maternal toxicity and reduced fetal body weights occurred at sulopenem etzadroxil doses associated with sulopenem plasma exposures approximately 0.1 and 0.2 times, respectively, the clinical sulopenem exposure for the MRHD of sulopenem etzadroxil.”
✓ VerifiedUS prescribing informationSource ↗