Study lengthAcceptedBeyond the letter
No long-term repeat-dose toxicity study in cynomolgus monkey
Why: 10-fold exposure margin not feasible due to immunosuppression and severe infections requiring antibiotics · Pharmacology or kinetics
“In their advice, the CHMP had acknowledged that evaluating doses corresponding to a 10-fold exposure margin when compared to the exposure in the MS patients would not be feasible due to immunosuppression and severe infections.”
✓ VerifiedEMA assessment report, p. 25Source ↗ “Overall, the CHMP had concluded that no further long-term repeat dose testing in cynomolgus monkey was warranted.”
✓ VerifiedEMA assessment report, p. 25Source ↗ CarcinogenicityAcceptedBeyond the letter
No carcinogenicity testing for a repeated-course immunosuppressive therapy
Why: No appropriate animal model; indirect tumorigenicity risk from prolonged immunosuppression already well established; prior CHMP scientific advice · No relevant species · Weight of evidence
“The CHMP also considered acceptable that no carcinogenicity testing was performed, taking into account the lack of an appropriate animal model, the well-established risk of indirect tumorigenicity caused by prolonged immunosuppression and the previous scientific advice provided by the CHMP.”
✓ VerifiedEMA assessment report, p. 25Source ↗ SpeciesAcceptedBeyond the letter
Reproductive and developmental toxicity studied in huCD52 transgenic mice instead of monkeys
Why: Neutralising anti-drug antibodies in a proportion of monkeys · No relevant species
“Cynomolgus monkey was not considered an appropriate species for reasons of anti-alemtuzumab antibodies developing in proportion of monkeys, which in some cases could exert a neutralizing activity. The CHMP also considered that the studies were conducted in compliance with the CHMP scientific advice.”
✓ VerifiedEMA assessment report, p. 26Source ↗ Safety marginVerdict not stated
Developmental toxicity NOAEL in transgenic mice below clinical exposure by Cmax; 0.6- to 4.4-fold by AUC
“Based on Cmax values, the exposures were significantly below those observed in the clinical setting, following administration of the recommended therapeutic dose. Higher exposure margins were established by the applicant based on AUC values obtained in a PK study. The use of these AUC data yielded exposure margins of 0.6- to 4.4-fold.”
✓ VerifiedEMA assessment report, p. 26Source ↗ Efficacy modelAcceptedBeyond the letter
No proof-of-concept studies in the EAE model of multiple sclerosis
Why: Clinical experience with alemtuzumab in MS already available · Human data
“No proof-of-concept studies in this model were conducted by the applicant. However, as clinical experience with alemtuzumab in the treatment of MS was already available at the time huCD52 transgenic mice were developed and characterised, the lack of these studies was considered acceptable by the CHMP.”
✓ VerifiedEMA assessment report, p. 24Source ↗