Currently, only 10% of the drugs that enter Phase I receive marketing approval from the U.S. Food and Drug Administration (FDA), with unmanageable toxicity accounting for approximately 30% of the clinical failures for investigational new drugs (INDs). Safety-based discontinuation of INDs is mainly associated with cardiotoxicity (which is also one of the most common reasons for the withdrawal of marketed drugs).

Last year we worked alongside authors from Amgen and published data in support of refining the hERG testing strategy for silencing RNA (siRNA). In accordance with the ICH S7B guidelines, an in vitro assay targeting the hERG channel forms a crucial component of the integrated risk assessment for delayed ventricular repolarization. The function of hERG may be influenced by either direct (acute) mechanisms or indirect (chronic) mechanisms. While some approved oligonucleotide therapeutics have submitted hERG data to regulatory bodies, gathered using protocols akin to small-molecule testing (with an incubation time <20 min, indicative of acute effects), oligonucleotides operate via distinct mechanisms and timelines (notably indirect effects).

This year’s Cambridge Ion Channel Forum (CICF) took place at AstraZeneca’s new world class facilities at The Discovery Centre (DISC) at the Biomedical Campus in Cambridge, UK. Upon arrival representatives from academia, biotech, pharma and contract research organisations were all catching up with old friends and making new connections, while enjoying lunch and an interesting selection of posters.

We generated a stable cell line expressing the lysosomal channel TRPML1 at the cell surface. First we validated this on manual patch-clamp and went on to develop robust assays for our higher throughput screening platforms, Qube 384 and FLIPR Penta, which are capable of detecting TRPML1 modulators for drug discovery.