Antisense startup Stoke Therapeutics secures another $90M in series B funding
Led by former Sarepta CEO, antisense startup Stoke Therapeutics has raked in $90 million in series B financing, following up the $40 million announced earlier this year.
Stoke licensed its technology, the so-called Targeted Augmentation of Nuclear Gene Output (TANGO), from Cold Spring Harbor Laboratory’s Adrian Krainer, who is credited as the inventor of Biogen’s $BIIB spinal muscular atrophy drug Spinraza. The $90 million in funding comes from RTW Investments with participation from founding investor Apple Tree Partners, that supplied the original $40 million injection in January.
The holy grail of gene therapies is to develop a treatment that is curative with a single dose, but so far, research has shown that the level of protein produced as a result of this type of therapeutic intervention can fluctuate from patient to patient, its durability remains in question and is expensive to manufacture because scientists must engineer viruses to deliver the gene-therapy to the patient. Stoke is developing so-called antisense oligonucleotide medicines, by taking aim at diseases areas that are often not amenable to traditional gene therapy, because the gene size is too big, or to gene editing, as the therapeutic needs to be titratable. Stoke is betting on stabilizing the protein manufactured by treated cells with its TANGO technology, which is designed to identify gene segments that can be targeted by drugs to dial up the level of protein produced. The company is then developing RNA drugs to then harness these targets.
Controlling the amount of protein produced following therapy is particularly significant in autosomal dominant diseases — such as genetic causes of epilepsy — in which mutations in just one copy of a gene adversely impact protein production. An over-production of protein in such cases could be equally catastrophic. Stoke’s lead experimental drug for Dravet syndrome — a rare and catastrophic form of intractable epilepsy that begins in infancy — is expected to be ready for clinical investigation by early 2020, Stoke said on Tuesday. The drug is designed to up-regulate production of a protein missing in patients with Dravet syndrome by targeting RNA splicing. The antisense oligonucleotide is suspended in saline and delivered via spinal injection, and will likely be administered every four months or so.
This story was updated with information from Stoke.