Stoke Therapeutics nabs $90M series B for oligonucleotide work

Migraine headache/epilepsy brain image
The startup is currently focused on treating Dravet Syndrome, a rare, lifelong form of epilepsy. (CC0 Creative Commons.)

Stoke has completed a meaty $90 million second funding round as the startup eyes getting its leading candidate into the clinic by 2020.

The Bedford, Massachusetts-based biotech said it will also push on with work across its pipeline of antisense oligonucleotide medicines in other severe genetic diseases.

The financing round (PDF) was led by RTW Investments with help from founding investor Apple Tree Partners. New investors include RA Capital Management and Cormorant Asset Management, as well as a host of others.

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This builds on the $40 million series A it grabbed back at the start of the year. Stoke licensed its tech, dubbed Targeted Augmentation of Nuclear Gene Output (a.k.a. TANGO), from scientific founder Adrian Krainer of Cold Spring Harbor Laboratory.

Stoke said it has “identified thousands of genes that could be addressed” by its TANGO tech, which targets nonproductive RNA splicing to increase gene expression, aimed at getting to the heart of monogenic diseases caused by loss or reduction of gene function.

The company said it is “rapidly advancing” its lead program in Dravet Syndrome, a rare, lifelong form of epilepsy that begins in the first year of life with frequent and/or prolonged seizures. Current treatment options are limited, and patients with Dravet face a 15-20% mortality rate, according to the Dravet Syndrome Foundation.

Its early-stage pipeline also includes drugs targeting other diseases of the central nervous system, as well as diseases of the eye, ear, liver and kidney.

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“Our technology is designed to address, for the first time, the genetic cause of diseases like Dravet Syndrome so we can do more than alleviate symptoms—we can potentially prevent the long-term disabling consequences of these diseases,” said Ed Kaye, M.D., CEO of Stoke, and former Sarepta chief.

“We are delighted to have the support of such an outstanding group of crossover investors to speed our progress toward the clinic.”

Stoke joins Atlantic Healthcare and Ionis Pharma /Akcea in the antisense field, with the latter getting approvals earlier this year for its effort in Tegsedi (inotersen injection), an antisense oligonucleotide for certain patients with the rare disease hereditary transthyretin amyloidosis (hATTR), as well as Biogen's SMA drug Spinraza.