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Spring Bank Caps Off Breakout Year With Potential HBV Cure, But Don't Forget STING

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Hepatitis B virus may soon have a bona fide functional cure thanks to a $200 million biotech firm called Spring Bank Pharmaceuticals Inc (NASDQ:SBPH). Markets have taken notice of this and bid up Spring Bank’s market cap by 45% over the last year, as data to back up the claim keeps being accumulated.

The asset, inarigivir, is unlike other HBV antivirals in that instead of only attacking the virus directly and disrupting its replication, it also awakens the immune system against HBV to complete the attack. HBV shuts down a protein called RIG-I, responsible for activating a natural antiviral process within cells that stimulates the production of interferon. Inarigivir reactivates that protein, and by doing so, it restarts a natural immune process as well as disrupting HBV replication.

Recent results published earlier this month show significant antiviral effects on a low 25mg dose, and even more when combined with Gilead Sciences (NASDAQ: GILD) blockbuster drug Viread. This on its own wouldn’t be particularly exciting because HBV antivirals already exist and work well enough to keep HBV at bay, but not enough to functionally cure it. Inarigivir unique is could lead to a functional cure.

HBV antivirals like Viread work, but they don’t finish the job. Eventually, the virus makes a comeback. With a functional cure, it doesn’t. This is what has prodded Gilead to work together with Springbank, a company just one five-hundredth its size.

Biotech markets seem to already be aware of the tantalizing possibility of an HBV functional cure, and with a megacap like Gilead in the picture, it’s not just a pipe dream. But there is another aspect of Spring Bank that seems to have been overlooked as excitement around inarigivir continues to build. Granted, the second asset is early stage so attention would naturally be focused on the more developed asset.

In any case, Spring Bank’s second main asset is billed SB 11285. It is what is known as a STING agonist, STING being short for stimulator of interferon genes. The technology is similar to inarigivir because STING uses the same RIG-I protein among other proteins to stimulate an immune response to cancers, also based on interferon. One of the ways cancer gets around the immune response is through the same process of shutting down RIG-I interferon signaling. Reactivating it could have similar effects to inarigivir on HBV, at least that is the theory.

Preclinical data has been impressive, with a dose of 9mg/kg monotherapy in mouse models showing 95% tumor growth inhibition. That means tumors slowed their growth rate by 95% with just the monotherapy compared to control.

Research is still preclinical with Spring Bank’s STING asset, but trials are set to enter the clinical phase next year in liver cancer. In other cases of a small biotech like Spring Bank armed with a preclinical asset, there would not be all that much cause for excitement. In Spring Bank’s case, the asset is entering the clinic with the wind at its back. Investors are already clearly paying attention to inarigivir, Spring Bank is already working together with a giant in the HBV space on joint future trials, and the STING asset is a different application of what is a similar technology based on the same concept of immune activation through interferon signaling.

With Spring Bank advancing with inarigivir, it may eventually be an acquisition target for a company like Gilead, with whom it is already collaborating. A functional HBV cure would do quite well for Gilead in terms of reinvigorating its hepatitis assets, especially if planned trials with Viread and its new asset Vemlidy prove successful.

Springbank’s STING asset, using similar biological pathways, only adds to the company’s prospects, and while it is backburner, it should not be ignored.

Spring Bank is funded through the end of the decade, an added plus for a company its size. This should see it through Gilead’s Phase II study of inarigivir together with HBV antiviral Vemlidy, set to initiate at the beginning of next year. 

Disclosure: the author holds no positions in any of the stocks mentioned. 

The preceding article is from one of our external contributors. It does not represent the opinion of Benzinga and has not been edited.

Posted-In: contributor contributorsBiotech News FDA General


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