The basis for this seems compelling and results of current study due in fall, safety looks good so far. What does everyone think?
Excerpts from call transcript:
ARO-HBV is our third generation subcutaneously administered clinical candidate for the treatment of chronic
hepatitis B virus infection. Both first-in-human studies are designed to include a single-ascending dose phase
and a multiple-ascending dose phase that are essentially running in parallel. phase 1/2 design is intended
to rapidly get to meaningful readouts on safety and tolerability as well as single and
multiple-dose activity. We have now treated 38 subjects, 24 on active drug
and 14 with placebo, between the two programs and both candidates have been
well tolerated thus far. Of course the studies are still young and several additional
dose levels remain to be tested, but it is encouraging to see a favorable safety
profile to date.
During the quarter we presented clinical data at EASL from ARC520,
a prior generation compound for HBV. I want to highlight some of those data
because they represent what we see as a very encouraging proof-of-concept for the
use of an RNAi compound in HBV, and, therefore, are relevant to our ARO-HBV
program. The poster presentation included follow-up data for patients enrolled in the
Heparc-2001 multi-dose extension study. In the study, 8 chronic hepatitis patients
(5 e-antigen negative, and 3 e-antigen positive) received up to 9 doses of 4 mg/kg
ARC-520 once every 4 weeks with daily entecavir. Viral DNA, RNA, and antigen
knockdown were measured at regular intervals. Patients were monitored for an
additional 12 months following the last ARC-520 dose.
Key results include the following:
• Multiple doses of ARC-520 resulted in s-antigen reductions in all patients by
as much as 5.3 Logs. Where measurable, multi-log reductions were also
seen in e antigen, core related antigen, DNA and HBV RNA.
• We were pleased to announce that one e-antigen negative patient, while
remaining on entecavir, serocleared for all measurable viral markers
including s-antigen, core-related antigen, HBV RNA, and HBV DNA. We
believe this will represent a functional cure.
• 2 out of 3 e-antigen positive and 2 out of 5 e-antigen negative patients, or
half of the patients in the study, achieved productive and sustained host
responses. These were characterized by mild-ALT elevations coinciding
with continued reductions in various viral markers which persisted after
ARC-520 therapy was removed.
• Two patients that experienced sustained host responses but had not yet
serocleared, appear poised to potentially seroclear if the trends in the
decrease of viral markers continues.
We think they suggest that an RNAi compound like ARO-HBV has the potential to be a backbone therapy in combinations aimed at achieving a functional cure of HBV. To us and many KOLs that we interact with, these data look as though ARC-520 treatment may have led to an awakening of the immune system,
which is the key requirement for functional cures to occur and be sustained. Keep
in mind that ARC-520 was designed to be active against all cccDNA derived
mRNA transcripts, but missed transcripts from integrated DNA. ARO-HBV
specifically addresses this deficiency. So we are more confident than ever about
ARO-HBV and we are eager to see if this translates into improved patient
outcomes or broader coverage of different patient populations.