Arrowhead Pharma Wins in Midstage Hepatitis Study

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Arrowhead Pharmaceuticals Inc. (NASDAQ: ARWR) saw its shares make a handy gain early Wednesday after the firm presented new data from its midstage study for the treatment of hepatitis B (HBV) infection.

These results were presented at the 22nd biennial HEP DART meeting held in Kona, Hawaii, and they indicate that multiple doses of an RNAi-based therapy may lead to a host response that is sustained after therapy is concluded.

For some quick background: the HEP DART meeting is an assembly of medical professionals and researchers, sharing ongoing drug development processes in the treatment of viral hepatitis, NASH and co-infections.

A significant reduction from baseline in HBV surface antigen (HBsAg) was achieved seven months following the administration of the last dose of ARC-520, with the lowest absolute level observed being just above the lower limit of HBsAg quantitation.

The results also showed key evidence for the first time that two of three (66.7%) HBV e-antigen (HBeAg) positive patients and two of five (40%) HBeAg negative patients treated with an RNAi-based therapy achieved a sustained host response off therapy.

Bruce D. Given, M.D., COO and head of R&D for Arrowhead, commented:

We believe that achieving a functional cure of chronic hepatitis B infection will require a sustained host response, which is likely to be immune mediated. In our Phase 2 study of ARC-520, multiple patients saw continued reductions in key HBV markers long after ARC-520 treatment ceased. These data represent the first clinical evidence that an RNAi-based approach can lead to the type of favorable sustained host response that we have always believed is possible. Achieving this result with ARC-520, which was not designed for activity against HBV s-antigen produced by integrated DNA, provides us with further confidence that our new RNAi-based compound, ARO-HBV, which is designed to silence the production of all HBV gene products, including transcripts derived from integrated DNA, has a good chance of being a backbone therapy for combinations intended to cure chronic HBV.

Shares of Arrowhead were up 7% at $3.57 early Wednesday, with a consensus analyst price target of $3.63 and a 52-week range of $1.20 to $4.54.