The historical context for this commentary can be found in this blogpost. This latest report, based on activity-based profiling (ABPP), constitutes the first open biochemical investigation of BIA 10-2474 (1). The ABPP results show it inhibits several lipases that are not targeted by PF04457845, a highly selective and clinically tested FAAH inhibitor. In addition BIA 10-2474 (but not PF04457845) produced substantial alterations in lipid networks in human cortical neurons. The authors are appropriately cautious in not over-extrapolating their findings to causality of pathology recorded in the unfortunate patients (see clinical report in PMID 27806235). However, biochemical and pharmacological questions still remain. One of these is that, given the initial binding interaction is no less than three orders of magnitude lower that PF004457845, it’s not entirely clear why 10-2474 was chosen as the lead. Another question is the basic kinetic parameters for purified enzymes (not just crude cell extracts in vitro) are still not available. This should include at least two methods for confirming irreversibility (e.g. IC50 vs pre-incubation or using a 10-2474 radiolabeled derivative). Word has it that a BIAL paper is in preparation so this aspect might be addressed by new results. Note also there are now two compound suppliers in PubChem offering BIA 10-2474 so more experimental reports could be expected.
The GtoPdb entries below have been updated with key interactions from this paper and will go live at the next release.
(1) van Esbroeck ACM et al. (2017). Activity-based protein profiling reveals off-target proteins of the FAAH inhibitor BIA 10-2474. Science, 356(6342): 1084-1087 [PMID:28596366]
Comments by Chris Southan (@cdsouthan)