Accelerating safe drug development: an ideal approach to approval

Daphnia magna and Xenopus laevis as in vivo models to probe toxicity and uptake of quantum dots functionalized with gH625

The use of quantum dots (QDs) for nanomedicine is hampered by their potential toxicologic effects and difficulties with delivery into the cell interior. We accomplished an in vivo study exploiting Daphnia magna and Xenopus laevis to evaluate both toxicity and uptake of QDs coated with the membranotropic peptide gH625 derived from the glycoprotein H of herpes simplex virus and widely used for drug delivery studies. We evaluated and compared the effects of QDs and gH625-QDs on the survival, uptake, induction of several responsive pathways and genotoxicity in D. magna, and we found that QDs coating plays a key role. Moreover, studies on X. laevis embryos allowed to better understand their cell/tissue localization and delivery efficacy. X. laevis embryos raised in Frog Embryo Teratogenesis Assay-Xenopus containing QDs or gH625-QDs showed that both nanoparticles localized in the gills, lung and intestine, but they showed different distributions, indicating that the uptake of gH625-QDs was enhanced; the functionalized QDs had a significantly lower toxic effect on embryos’ survival and phenotypes. We observed that D. magna and X. laevis are useful in vivo models for toxicity and drug delivery studies.

Approving molecularly targeted drugs: different approval processes for cytotoxic agents

BACKGROUND

Recently, the approval of some molecularly targeted drugs has been questioned, due to differing opinions on their risks and benefits. The approval process remains a challenge in regulatory science.

METHODS

We analyzed the molecularly targeted drugs listed in the 2013 Medical Formulary. For the 21 identified drugs, 32 published Pharmaceuticals and Medical Devices Agency (PMDA) reports were open to the public. Data regarding clinical trials were extracted from these reports and assessed in order to clarify the characteristic examinations required for the approval of molecularly targeted drugs.

RESULTS

There was no correlation between the application year and the time between application and approval (p = 0.139). The median number of clinical trials in these reports was 5 (range 1-22). Phase III studies were not included in the assessment materials for 11 reports. A survival benefit was demonstrated for six of the 32 drugs. The PMDA issued approval terms, including all-case surveillance and additional clinical trials, for 24 of these 32 drugs.

CONCLUSION

Molecularly targeted drugs were approved by the PMDA using a flexible process based on drug safety and efficacy. Doctors and patients who are administering or receiving these drugs should be fully informed about the lack of Japanese data assessment during these approval processes.