Development of anti-sense oligonucleotides as a therapeutic for cancer pain through selective block of sodium channel pain targets

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Project Summary: Development of anti-sense oligonucleotides as a therapeutic for cancer pain by selectively reducing sodium channel expression Effective treatment of cancer pain is a large unmet medical need, as opioids, the current standard of care lack efficacy and cause addiction. For end-of-life cancer patients and estrogen receptor- positive breast cancer patients with long life expectancy, more effective therapeutic approaches for pain are needed. Antisense oligonucleotides (ASOs) bind to and induce degradation of RNA transcripts with specific sequences, enabling selective protein knockdown (KD) with long duration of action (weeks or months), to deliver long-term relief. ASOs can also be used in combination, to reduce the expression of multiple proteins for increased efficacy. As a modality, ASOs have been successfully applied in the clinic to treat severe neurological disease. We target the voltage gated sodium channels (Navs) selectively expressed in dorsal root ganglion neurons (Nav1.7, Nav1.8 and Nav1.9), which are implicated in pain transmission and specifically in cancer pain. Reduction of channel expression aims to overcome the limitations of small molecule state-dependent channel blockers, if the channel should be blocked in a state-independent manner for efficacy. Preliminary results with our designed ASOs show >70% mRNA KD for several Navs in rat dorsal root ganglion sensory neurons (DRGs). We apply a novel platform to design ASOs for specific knockdown of Nav channels. For pain targets and indications, QuellTx also has an exclusive worldwide license to breakthrough technology: (i) An in vitro cellular model for cancer pain (developed through SBIR funding by NCI), where primary DRG neurons are bathed in a physiologically-relevant mixture of inflammatory mediators secreted by tumors, or ‘cancer-SPARC’. The SPARC- treated neurons become hyperexcitable, mimicking the cellular pain response. (ii) An all optical electrophysiology high throughput readout for neuronal excitability (Optopatch), allowing recordings from 100s of individual neurons in parallel with high temporal resolution. This platform enables us to determine the impact of modulating expression of Nav1.7, 1.8 and 1.9, alone or in combination, on the pain-in-a-dish phenotype. In Phase I we propose to leverage our ASO design capabilities, combined with the breakthrough technology to: (a) identify ASOs for selective modulation of expression of Nav channel pain targets and (b) determine the combination of ASOs and %mRNA knock down for maximal phenotypic effect in vitro. We will select ASOs that efficiently knockdown Nav channels and reverse the pain phenotype induced by cancer-SPARC. In Phase II we will determine the PK/PD (%mRNA KD) in rats, and the % mRNA KD needed for efficacy in a rat model of cancer pain, while optimizing human cross-reacting with cynmolgous monkey (cyno) ASOs for efficacy in human DRG neuronal models of pain. Our ultimate goal is to advance optimized ASOs to IND enabling toxicity studies in rat and cynos, leading to a therapeutic to treat cancer pain in patients.