One Pitfall to Look Out for in RNAi Therapeutics

RNAi Therapeutics have turned the corner to being a generally accepted drug modality.  Following years of ridicule and benign neglect, the industry just celebrated the FDA approval of a 2nd drug, Givlaari for the treatment of acute hepatic porphyria. This was followed in short order by the $9.7B acquisition of The Medicines Company by Novartis for its cholesterol-lowering RNAi drug candidate, Inclisiran, a harbinger for how RNAi medicines will change the game in cardiovascular risk management.

Amid all the understandable investor excitement, it is probably a good time to reflect on the potential pitfalls as we move into a world where RNAi Therapeutics dominate liver-related diseases and advance into new big areas such as the CNS and ocular disease.  Remember, investor, it takes one safety event for the most highly valued programs like HBV RNAi candidate AB-729 by Arbutus Biopharma, Arrowhead Pharmaceutical’s ARO-AAT, or the Lpa program by Silence Therapeutics to decimate your investment by half or more.

Off-targeting safety, off-targeting safety, off-targeting safety

When the discovery of RNAi was rewarded with the Nobel Prize in 2006, the Andy Fire and Craig Mello hammered home a message that would resonate for the years to come: to make RNAi Therapeutics, it’s all about the delivery!

Delivery, delivery, delivery

But as the liver has been conquered and the industry is chewing on a number of liver-related therapeutic opportunities and opening up opportunities in new areas, we still have to fully understand the odds of seeing program failures due to the difficult to predict consequences of off-targeting.

Off-targeting is the moderate knockdown of sometimes dozens of genes sharing sequence homology to the target gene.  This was shown over a decade ago and soon thereafter shown to be addressed by using simple modification strategies.

This, however, was at a time when the delivery mantra was practiced and nobody wanted to risk reducing knockdown efficacy by simultaneously considering off-targeting in their RNAi trigger designs.  I was therefore upset, as it turned out rightfully so, that Alnylam let Nastech essentially go bankrupt a decade ago when it should have acquired rights to Nastech's then industry-leading off-target-mitigation technology.

Alpha-1 Antitrypsin as testbed

Alnylam would have to pay dearly for its pride in never treating a smaller competitor well, even if it served its own interest, with off-targeting manifesting itself in markers of liver toxicity in first-generation clinical programs like chronic HBV and alpha-1 antitrypsin-related liver disease.

These two indications, unlike the now approved AHP indication for Givlaari which addresses symptoms outside of the liver, represent the most exacting off-targeting challenge as they affect liver health directly and any further exacerbation of liver stress should be avoided.  

As a result, Alnylam dug out the old off-targeting literature and in their incarnation added a GNA modification at position 7 of the guide strand while, for experimental purposes, leaving the rest of the first-generation molecule unchanged. Translational science at its best (!) and the industry can be thankful for it.

Indeed, for both the ESC+ chemistry ALN-AAT02 and ALN-HBV02 no liver enzyme elevations (above 3x ULN) were observed in 49 subjects tested, whereas 3 of 33 had such elevations with the ESC-only versions.

In Arrowhead’s case, there also were no ALT elevations >3x ULN.  However, 3 treatment-emergent grade 1 ALT elevations not exceeding 2x ULN were reported in the 28 normal healthy volunteers receiving ARO-AAT.  I am curious to see the individual time curves and the doses at which they occurred.  It is certainly an area to watch for that program as it only now moves into patients. 

Add to this considerable uncertainty about patient selection, dose and duration required to have an impact on AAT liver disease, increasingly analysts topping their price targets by the day may have to re-think how they value this program (see disclosure below).

Further behind, we have to see how Silence Therapeutics and Arbutus have addressed off-targeting with first data expected in 2020.  While Silence has avoided indications directly affecting liver health (iron overload, cardiovascular disease), Arbutus with its HBV indication will have a steeper hill to climb, although the pay-off for investors in this $80 market cap company should be considerable should it climb it come Q1 2020.

Personally, my guesstimate for non-optimized GalNAc designs would be a 50% chance of off-targeting success, also depending on preclinical vetting (after all, the very clean $9.7B Inclisiran is such a design); a 85% off-targeting success for optimized designs. 

Disclosures: long Silence Therapeutics, Arbutus Biopharma; short Arrowhead Pharmaceuticals; no position in Alnylam.

AASLD Abstract Continues to Support Promise of ARO-HBV, but with a Twist

Yesterday, Arrowhead revealed the abstract for data on its new HBV RNAi drug candidate to be presented at the big annual Liver Meeting in November (AASLD).  The data continue to support highly potent knockdown of not only the surface antigen (HBsAg), but also other HBV components.

Dose response issues

When Arrowhead announced initial first-in-patient knockdown data from its 3^rd generation HBV RNAi candidate ARO-HBV, I found it suspicious for them to only reveal data for the 100mg and 200mg cohorts although more data was available at the time.  Curiously, the new data seem to suggest that there was no apparent benefit from going higher than 100mg in dose, at least when dosed with the current monthly frequency. 

Whether there is significantly worsening safety with increasing dose remains to be seen.

HBeAg positive/negative dichotomy

Similarly (but not as earth-shattering for sure) to the history of a prior HBV RNAi candidate by the company before, ARC-520, however, Arrowhead was able to learn more about its drug candidate as they went along in the study.  In particular, the first dose escalation cohorts (100, 200, 300, and 400mg monthly x3) encompassed a mix of HBeAg positive and negative patients, with 13 out of 16 being HBeAg negative.    

When Arrowhead then decided the last 2 cohorts to be just HBeAg positive, a remarkable increase in drug response was observed: whereas it took the predominantly HBeAg-negative patients 70-90 days to achieve 1.5log reductions in HBsAg, it looks like the pure HBeAg-positive patients only take 30-40 days to achieve the same.

Ergo, the reason why no clean dose response had been seen in the first cohorts is best explained by the fact that they were mixed and at that small cohorts.

Trigger choice likely explanation

ARO-HBV comprises 2 RNAi triggers: one that targets all (intact) HBV mRNA (X trigger) and one that makes sure the surface antigen is hit (S trigger) even in those patients with integrated HBV.  These typically lose the corresponding DNA element targeted by the X trigger during integration.

In the early days of RNAi, there was some controversy about the usefulness of using 2 or more triggers against the same target in terms of knockdown potency and specificity.  When I first started to practice RNAi in the lab in 2003, it was my experience that when you combined a very potent trigger with a less potent one, the knockdown was less than with the highly potent one alone.  As a result, I am a firm believer in the concept of RNAi trigger competition.

In the case of ARO-HBV it means that in HBeAg negative patients that have lost the X-trigger DNA, there will be one sterile/inactive trigger somewhat blunting the potency of the active one.

HBV biology is certainly complex and downstream events could also account for final knockdown differences.  Accordingly, in the HBeAg-only cohorts  it appears from the early observations that the nuc-experienced patients that in previous studies corresponded to patients that had lost the X-trigger-targeted elements by study enrollment not only responded as well, but in fact slightly better than the nuc-naïve patients.  It will therefore be important to learn more about their HBV integration status at AASLD to confirm or disprove the competition theory.

Review of Recent RNAi-Related Developments

The last 2 weeks have been busy ones in the lands of RNAi Therapeutics.  Here, I would therefore like to offer my take on the most important developments.

Alnylam’s Primary Hyperoxaluria Drug Breezes Through Clinic

With 20 subjects on Lumasiran, a GalNAc-RNAi targeting glycolate oxidase, for a median of 7 months, the investigational treatment for type I primary hyperoxaluria (PH1) ismore and more looking like a solid drug.  If the data presented last week at a Paediatric meeting in Turkey hold up in another 30 patients, it should fly through approval onto the market by the end of 2019.

While the relatively small numbers in each cohort has caused a bit statistical noise, it seemed like 3mg/kg monthly gives you an advantage over 1mg/kg monthly or 3mg/kg monthly in terms of the key biomarker urinary oxalate.  Interestingly, the company has chosen 3 times 3mg/kg monthly as the loading dose regimen in the now ongoing pivotal ILLUMINATE-A trial to be followed by dosing every 3 months. , the initiation of which the company has just announced.    

The core double-blind portion of the trial runs for only 6 months, so I am a bit puzzled how much the trial can inform on the value of the loading dose regimen and whether quarterly maintenance doses are sufficiently effective.   In any case, the trial design apparently was blessed by the FDA (incl. the urinary oxalate lowering primary endpoint), so surely they will know (e.g. based on preclinical animal data).

Regarding the competition with the primary hyperoxaluria drug candidate from Dicerna, the approximately 2/3 lowering of urinary oxalate and essentially all patients getting into a range considered safe and an unremarkable safety profile sets a high hurdle for the upcoming data presentation of DCR-PHXC at ASN later this month.

Arbutus HBV-RNAi Drug About to Die   

Yesterday, Arbutus provided an update on its LNP-enabled RNAi drug candidate for the treatment of chronic HBV (ARB-1467) and it does not bode well.  Similar to most other drug candidates attempted and barely tried, ARB-1467 should be canned in the not-too-distant future. 

In a combination study testing ARB-1467 in chronic HBV patients on nucleoside reverse transcriptase inhibitor tenofovir, probably only 1 in 6 patients hit a pre-defined criteria in terms of HBsAg lowering that would allow the patient to then receive immune booster PEG-Interferon.  The not very forthcoming revelation and the fact that the data was mentioned even after dropping another shoe that its small molecule HBV RNA destabilizer is also biting the dust makes it clear that not even the company sees much value in ARB-1467.

What an utter disaster this company has been since its inception as a HBV solutions entity.

Arrowhead Early HBV Deal Further Validates

Last week, shareholders in Arrowhead Pharmaceuticals got a lesson in biotech investing as it shares have given up ~1/3 of its value following a nice deal with Johnson&Johnson for the leading HBV knockdown asset in the space, ARO-HBV.

The deal gives Arrowhead a solid $250M in financing, including a $175M upfront fee and a $75M investment in company stock at a premium of ~50% to current trading.  While this avoids an imminent dilutive secondary share issuance- the company had been running low of cash- the ‘up to 15%’ in royalties from future sales of early phase II-stage ARO-HBV is clearly disappointing.  The relatively low royalty despite of it having confirmed strong HBsAg knockdown in patients can be explained with the fact that Arrowhead has avoided bearing the full risk of having to show proof-of-concept of HBV control.  This despite of having earlier paraded results obtained with an earlier DPC-based RNAi candidate (ARC-520) as strong evidence that RNAi can achieve such immune control.

While Arrowhead got punished for playing it safely, it can now focus on commercial home-run indications with highly validated targets and transition to being a broad platform company with a wholly owned attractive lead candidate in ARO-AAT.  Indeed, Arrowhead may emerge as the leading RNAi company as Alnylam, with a market cap ~8x that of Arrowhead, is still burdened by late-stage RNAi drugs with suboptimal specificity.

While humiliating, this serves Alnylam as a good reminder to also value innovation by the direct competition (note: specificity-enhancing technology now adopted by Alnylam has been available for a decade and could have been had for peanuts, e.g. from now defunct RNAi play mdRNA/Nastech).  Fittingly, today long-time archrival Silence Therapeutics issued a press release indicating that Alnylam is playing hard-ball with regard to Silence-owned IP purportedly covering ONPATTRO.

My guess is that Alnylam would rather risk an injunction and deprive patients of a very good medicine than to submit to what appear to me legitimate demands of a competitor.

Akcea’s antisense drug for TTR amyloidosis gets FDA nod

Last Friday, Akcea’s TTR drug TEGSEDI (licensed from Ionis) finally got FDA marketing approval for patients suffering from TTR-related polyneuropathy.  As expected from the delay in the approval process, TEGSEDI’s approval is accompanied by hefty black box warnings highlighting thrombocytopenia and renal risks of the (non-GalNAc) phosphorothioate oligonucleotide.  

Furthermore, the REMS program calls for frequent blood monitoring, essentially negating the claimed at-your-home convenience advantage over competing RNAi drug ONPATTRO.  Add to the poor safety profile clear efficacy disadvantages and pricing at parity with ONPATTRO, ONPATTRO should clearly win out in the marketplace.

Having said that, the TTR community is relatively small and key opinion leaders with relationships to a given drug company tend to support the drugs from the same company.

Second-Tier RNAi Therapeutics Companies Starting to Deliver Clinically

Alnylam has had a 3 year head-start on the competition with GalNAc RNAi Therapeutics, but now additional companies are populating the field with actual clinical data.  While the knockdowns appear robust and the chemistries well tolerated, therapeutic utility and the potential of liver toxicity from off-targeting will have to be demonstrated in upcoming longer-term studies.

Dicerna clinically validates new target for primary hyperoxaluria

Dicerna used to be the leader in applying RNAi Therapeutics to primary hyperoxaluria (PH), an orphan genetic condition caused by dangerously high levels of oxalate in the blood.  Oxalate crystallization and deposition may then poison first the kidneys and then various organs leading to premature death.  Unfortunately, as its old LNP technology proved to be impractical, Alnylam's directly competing program targeting glycolate oxidase (GO) assumed the lead.

When Dicerna then came up with a GalNAc-based follow-up candidate (DCR-PHXC), it also chose a new target: hepatic lactate dehydrogenase (LDHA), a target which may have be applicable also for forms of PH beyond the most frequently diagnosed PH1 and for which GO is a suitable target.  Cynics may suspect that the new target was not chosen because it is the better one, but in an effort to provide differentiation over more advanced competition.  To wit, first-mover advantage can be significant in the orphan drug arena.

Perhaps due to its long-standing, deep relationship with the PH community, Dicerna has been able to recruit patients more quickly than I had suspected (in light of Alnylam's parallel recruitment efforts) in its first-in-patient study.  First data from this study (PHYOX) were revealed last week.  To their relief, LDHA knockdown resulted in oxalate lowering in all 9 subjects (8 PH1, 1 PH2) tested.

Following a single-dose of either 1.5mg/kg or 3.0mg/kg, at least 30% reductions in urinary oxalate were seen and all or almost all subjects got to urinary oxalate levels at or below 1.1mmol/24hrs/1.73m2, a level predictive of end-stage-renal-disease freedom.

More detailed data will be presented later this year where we will get a better sense in how the results stack up with those of Alnylam.  Earlier this summer, Alnylam reported 64% mean urinary oxalate reductions relative to baseline before following more than one dose.  Another area of concern is that it appears that 3 out of the 9 injections resulted in injection site reactions (ISR).  To see ISRs is not surprising per se, but the frequency appears to be on the high end based on early experience and could be a competitive disadvantage.  Similarly, no word was said about liver enzymes.

Given that Dicerna has been rushing the PHYOX trial without so much as testing multi-dose regimens, I expect the regulatory agencies to demand at least 2 dosing schemes in the upcoming pivotal trials.  A nightmare scenario would see Dicerna being sent back to phase II to test the safety of multi-dosing, a fate that Regulus Therapeutics had suffered before in Europe.

Disclosure: Over the last few months, I have been largely playing the volatility of DRNA- both on the long and short side.  Looking ahead to the end of the year, I would be hesitant of taking a substantial long position due to a market cap approaching $1B with the potential of negative surprises both on safety and efficacy when more detailed PHYOX data will be presented.  On the other hand, a deal (such as on the IND-ready mystery candidate) could provide a catalyst to the upside at least in the short-term.

Arrowhead sees best HBsAg knockdowns so far with new GalNAc candidate

When similar to Dicerna Arrowhead had to retool its lead programs with the GalNAc technology, one question was whether they could achieve knockdowns as potent as with DPC delivery which employed explicit cell penetrating chemistries.  It was therefore cause for celebration when the company reported -2log HBV surface antigen (HBsAg) knockdowns at the World Gastroenterologists Summit, better than with ARC520 and ARC521 before (slides here).  Also, the knockdown was observed regardless of e-antigen status, but that was to be expected with the new sequence design.

Intriguingly, following 3 monthly injections, the knockdown curves still kept coming down, making it almost look like HBV can be beaten into submission by the knockdown effect alone and without the help of an immune boosting effect.

Unfortunately, only HBsAg results from the 100mg and 200mg monthly dosing cohorts were disclosed even though the company had dosed 9 other dosing and patient cohorts.  Based on cohorts 8-11, it appears that best results may in fact have been obtained with the 300mg monthly regimen which will probably be disclosed in the run-up to this year’s AASLD meeting.

Similar to Alnylam in 2014, after showing impressive RNAi target knockdowns in the clinic, the wait is now on to show that the knockdowns will translate into therapeutic benefits.  Given the speed of the company’s execution in general, I would expect pertinent data to emerge from the HBV program in late 2019/early 2020.

Disclosure: similar to Dicerna, I have been recently playing the volatility of ARWR stock, getting long as it had been consolidating around the $14 level, then selling and going short into last week’s 50% spike to a $2B market cap.  With the puts I then sold ($21 and $20 September strikes), I have a ~10% cushion should the stock zoom past $21 by the September options expiration and my max gain is ~13%.  This is intended as a short-term trade

Regulus Therapeutics Declares MicroRNA Therapeutics Bankrupt

Once considered a new star on the biotech firmament, the most prominent microRNA Therapeutics company is going from bad to worse fast.  

Last week, Regulus Therapeutics announced that both of its clinical programs in Alport’s Syndrome and autosomal dominant polycystic kidney disease (AKPKD) had been voluntarily halted for financial and preclinical reasons. Instead, the company will now try to renegotiate the Alport deal with Sanofi and use its remaining resources to focus on a preclinical program for HBV.

Management not in control

The program pauses follow a string of other setbacks over the last 3 or so years. Most prominently, it discontinued a highly promising candidate for the treatment of HCV due to safety questions and having been a few years too late to a highly competitive game.  A slow early advancement of that miR-122 program was partly to blame for this.

After that, it has been one delay after another for various programs.  Partner AstraZeneca e.g. returned a liver-targeted metabolic program and the Alport's program has been hit by multiple delays and trial reconfigurations.

If this was not sufficient proof that managing a biotech company has been well above the paygrades of the multiple executive teams that have come and gone over the years, running out of cash in this genetically-focused biotech bull environment is simply unacceptable.  Even if microRNAs may have lost its early luster as targets for particularly complex diseases, I had thought that having exclusive access to the huge IP portfolios of parent companies Ionis and Alnylam for microRNA Therapeutics purposes would provide a powerful backstop when it came to accessing fresh capital.

With a market cap of less than $40M and last week’s ‘we’ve-run-out-of-cash news’ I was obviously wrong…

Chasing a 'safe' target

Since microRNAs which typically have a range of biologically meaningful targets are thus promising for treating particularly diseases of complex causes and manifestations, I would have thought that with the genetics gold-rush that we are now witnessing in neurology, not least because of antisense drug SPINRAZA, there would be much interest in Regulus Therapeutics there.

I understand that HBV is becoming a hot area again, with the skyrocketing valuations of Arrowhead, Dicerna, and Arbutus suggesting that high rates of functional cures are just around the corner.  Going after HBV with a microRNA, however, would seem like a surprising choice though given that in terms of direct antiviral activity, a microRNA approach should pale in comparison to the RNAi competition.  You would therefore think that Regulus is considering a immune reactivation-related microRNA target for HBV, but it is not clear to me which model they would be basing this on.  

Hey, management, at least show us some data to hang our hats on when you sell a preclinical concept as your future.

Or does choosing HBV betray that they have lost all confidence in their ability to deal with the biological complexity of microRNAs, instead seeking safety in just measuring simple viral knockdowns?

After the quasi-demise of microRNA diagnostics leader Rosetta Genomics, there is now the real prospect that the therapeutics counterpart will equally go belly-up soon.  In order to avoid that, Regulus needs new, confident management first and foremost as the main task now is to make the case for microRNAs as therapeutic targets.  Where are all the boastful biotech executives when you need them?

Dicerna Exploits HBV Biology For Less Frequent RNAi Dosing

Despite recent findings by Arrowhead Pharmaceuticals suggesting that finite treatment with an RNAi medicine might be possible in the search for a (functional) cure of HBV, less frequent dosing is always a plus.  It now seems that fresh HBV entrant Dicerna may have stumbled across a way to reduce dosing frequency and at the same time uncovered an intriguing piece of HBV biology involving the mysterious HBV X protein (HBx).

Search for perfect RNAi target site uncovers important HBV biology

Gene knockdown trigger selection has become critical in a highly competitive field featuring not only Arrowhead and Dicerna, but also Arbutus, Ionis (along with partner GSK), and the Alnylam-Vir alliance in the Western World alone.  This is because ‘by rotten luck’, Arrowhead found that an RNAi trigger that was designed to hit all the HBV transcript did not take into account the absence of the target site on transcripts that derive from host chromosomally integrated HBV.    

The finding that in many patients, e-antigen negative patients in particular, most viral transcripts derive from integrated HBV, has to be considered the most important new discovery in HBV biology and  disease progression since the finding of NTCP as the viral entry receptor.

This has established the selection of a target site upstream of the integration breakpoint as the new industry standard.  Little did we know that the search of the perfect RNAi target site should yield another fundamental insight into HBV biology that could also be therapeutically valuable and provide for some important competitive differentiation for late entrant Dicerna.     

HBx-sparing RNAi trigger has dramatic impact on HBV core protein localization

When scanning the HBV genome for target sites, Dicerna found that an RNAi trigger that hits all HBV transcripts except for HBx was associated with considerably more sustained gene silencing following a single dose (>>8 weeks in a mouse model where GalNAc-RNAi is generally less long-lived compared to humans) compared to an RNAi trigger hitting all HBV transcripts without exception (~3 weeks until knockdown was considerably lessened). 

Further underlining the longevity of the effect, Arbutus’ LNP-based formulation was only able to produce 1 week of good gene silencing in the same (HDI; slide 6) mouse model.

Interestingly, this effect was correlated with striking differences in the cellular localization of the HBV core protein: when all gene products were equally targeted, core protein was predominantly in the nucleus.  By contrast, core protein was almost exclusively cytoplasmic when HBx was spared.  Since phosphorylation of the C-terminal domain is known to be important for HBx nuclear trafficking, it was speculated that HBx may bind in that region and thus mask the nuclear localization signal.  This would be useful during the late stages of a viral infection when core protein would be needed for pregenomic RNA packaging and ultimately viral release.

The reason why gene silencing would be shorter lived when core was in the nucleus is likely due to its stimulating activity on transcription from the HBV cccDNA which would increase transcript dynamics and thus more quickly dilute out the anti-HBV-loaded RNAi machinery in the cytoplasm.

Indeed, in a non-cccDNA-dependent mouse model (e.g. more reminiscent of e-antigen negative patients), this beneficial effect was not observed.  

In summary, while the mechanistic basis of the differential silencing phenomenon remains to be fully fleshed out by further experimentation, Dicerna has found a way to quite dramatically extend gene silencing and thus decrease drug administration frequency.  This is a useful competitive feature in antivirals in general where drug resistance due to missed doses is always a concern and also simply due to patient convenience.

Disclosure: long DRNA.

New Arrowhead Data Shows RNAi Ratting Out HBV

When Arrowhead suffered its DPC fiasco a year ago, it got a chance to re-prioritize its pipeline.  It therefore caught my attention that despite the significant theory risk that still persisted, it chose HBV as one of its lead indications.

To wit, knocking down HBV genes promised to re-awaken the host immune system thought to be exhausted in chronic HBV patients.  The HBV surface antigen (HBsAg) had been regarded to be the main culprit for this exhaustion, although other gene products are now thought to play a role, too.

Previous update suggested long road ahead

When Arrowhead left off, clinical data had shown robust HBV gene suppression (~1-2log range) when the RNAi trigger target sites were present (in treatment-naïve e-antigen positive patients).  Curiously, in e-antigen negative patients where many HBV transcripts lack the ARC-520 target sites, a modest, protracted anti-HBV response could be observed.

Unfortunately, data presented this spring at EASL suggested that long, if not chronic RNAi dosing might be necessary since viral rebounds were seen in all but one subject once ARC-520 dosing had been stopped after half a year of treatment.

Chronic dosing, if indeed it can be shown to lead to a reduction of cirrhosis, liver cancer, and death, is conceivable with a subcutaneously administered RNAi agent.  The road, however, to proving such value and broad adoption in the clinic would be harder and longer compared to demonstrating host control of the virus after a finite treatment period.

New update shows host gaining upper hand

Based on the latest data presented yesterday at HepDART, including ~8 months of additional follow-up in the same patients, this may not be the case anymore.  This is because in 50% of the subjects (in 2 out of 3 e-positive and 2 out of 5 e-negative) given ARC-520 along with polymerase inhibitor entecavir, there have been sustained anti-viral responses after the initial rebound. 

In all cases, HBsAg continued trending down until the last time-point reported, and in 3 of these 4 subjects HBsAg was approaching the limit of detection.   Intriguingly, this was accompanied by a modest spike in liver enzymes, consistent with the host immune system regaining the ability to spot and remove infected hepatocytes. 

Of note, the HBsAg declines are more robust (5.0, 3.1, 2.0, and 0.6) and faster than would be expected based on entecavir treatment alone (~0.5log per year).

Since the enzyme elevations generally followed on the heels of the viral rebound, it is possible that treatment cessation and getting HBV to come out of hiding is actually beneficial.  Nevertheless, in the one subject (patient 01-7985) where there was no viral rebound, ALT values still rose.  

Experimenting with treatment schedules will therefore be an important component of future HBV trials.

In the meantime, we can look forward to an update on the same subjects after another few months. Could it possibly be that we are witnessing  the first HBsAg clearances and host control of HBV brought about by RNAi?

RNAi Companies Ought to Look Beyond Their Platform

This week, Alnylam announced in their roundabout way that it has discontinued the development of ALN-HBV for the treatment of chronic HBV infection.  Instead, it has come to an agreement with well-funded start-up Vir Biotechnology to select a new GalNAc-based RNAi compound, ALN-HBV02, which Vir will largely take control over clinical development.  Alnylam meanwhile retains considerable back-end loaded opt-in rights, milestones and royalties.  

As alluded to in a post last week, ALN-HBV seemed always doomed to fail due to target site selection issues. Also, Alnylam’s heart never really was into ALN-HBV with project leader Sepp-Lorenzino functioning as a one-woman show while competitor Arrowhead mobilized considerable internal and external resources.  She’s, of course, left the company not long ago.

We may never find out the real reasons for their decision although Alnylam would like us to believe that it was a specificity issue since ALN-HBV02 will now be ESCplus-based. Please don't fall into that trap.

My expectation is that ALN-GO1 for primary hyperoxaluria (PH) will suffer the same fate as the initial biomarker data from clinical studies have indicated that likely prohibitively high doses would be necessary to achieve robust oxalate lowering (a modest ~2x increase in glycolate biomarker at a single dose of 6mg/kg).

Once again, a much smaller competitor, Dicerna, has been running circles around RNAi juggernaut Alnylam.  Importantly, it has conducted detailed work on the biochemical pathway of oxalate metabolism and closely studied the natural history of the disease.  The reward was the discovery that the lactate dehydrogenase A (LDHA) is in all likelihood a much better target.

In hindsight it is quite clear that both HBV and PH were only chosen by Alnylam to scare investors away from their competition to cement RNAi dominance.  Not only that, it then filed a frivolous lawsuit against Dicerna alleging trade secret violations.

Will RNAi platform companies have to broaden their tech base?

Given the need to immerse oneself into individual diseases, and also as RNAi is about to open the commercialization chapter, frequently developing drugs for entirely new disease categories served by medicines, a new question arises for the industry: do I remain a platform company or do I have to open my technology base to best serve patient communities and shareholders?

While I do like to criticize Alnylam for shamelessly behaving like the industry's big bully, TTR amyloidosis is one of the diseases they deeply care about.  With 10-20k TTR amyloidosis patients in developed markets, a number that should grow due to increased disease awareness, better diagnosis tools and access, and hopefully prolonged lives, this could well develop into a $5B+ annual market over the next decade.

As the company behind what promises to be the first dominant drug for this disease and a next generation product candidate (ALN-TTRsc02) that should remove any doubt who owns TTR gene knockdown following on its heels, Alnylam would be irresponsible not to try and control the whole patient experience, including complementary non-RNAi treatment options.  In other words, Alnylam would cease to be a pure-play RNAi Therapeutics company while continuing to rely on RNAi for conquering new markets.

This evolution of corporate strategy, of course, is not new to biotechnology and has played out at companies like Vertex Pharmaceuticals (small molecules à cystic fibrosis focus), Biogen (recombinant proteins à multiple sclerosis/CNS focus), and indeed in the Oligonucleotide Therapeutics space before.

Sarepta, once singularly based on morpholino antisense technology, for example has been on a Duchenne muscular dystrophy (DMD) business development spree as their first antisense drug (EXONDYS51) was getting approved.  Sarepta sports a solid >$3B market capitalization illustrating that the financial markets reward such commitment to commercialization and category dominance.

On the other end of the spectrum is Ionis Pharmaceuticals.  

This company is happy to cease control over its groundbreaking compounds and disease insight quite early in their drugs' development paths. Consequently, it finds itself in situations where it either only gets a pittance from breathtaking medical and commercial successes such as SPINRAZA (for spinal muscular atrophy) or it gets caught with their pants down when a partner returns a compound late in the game as has just happened with IONS-TTR/Inotersen and GSK.

The market cap of Ionis, a company that shames $100B+ Big Pharma in terms of its pipeline and which will have close to a dozen compounds on the market and/or in pivotal clinical trials in a year or two, is comparatively paltry: $8B.

And the reason for this?  They are considering themselves a scientific company with a mindset of ‘we are better than organizations with corrupt sales departments’ that is difficult to find even in academia nowadays.  OK, management keeps drawing nice salaries and humongous stock/options rewards, so its really only shareholders that suffer.  

So as much as it hurts me as an RNAi scientists, when it comes to maximizing shareholder returns, the platform serves the purpose of capturing dominant footholds in new disease categories of high unmet needs, but this position has to be fortified by deep relationships with the patient community and an equally deep understanding of disease pathology.  And if necessary, develop and/or license complementary non-RNAi compounds.  

A word on the Arcturus-Janssen HBV deal

In addition to the Alnylam-Vir deal, another HBV RNAi-related deal was announced this week, namely between newly public Arcturus and Big Pharma player Janssen, a unit of Johnson & Johnson.

According to the agreement, Arcturus will work together with Janssen to develop an RNAi drug for HBV utilizing Arcturus’ intravenously administered RNAi triggers formulated in LNPs.   Arcturus uses fancy names for these components, but this is what's behind 'LUNAR' and 'UNA Oligomer Chemistry'. 

Given the availability of potent, but subcutaneous GalNAc-conjugation options in the industry, this interest by Janssen may come as a surprise to some and will serve Arbutus bulls as ammunition in claiming that Arbutus’ HBV RNAi LNP formulation has a future.  A Big Pharma deal after all is a knighthood in the industry.  

Still, I highly doubt it.

It is more likely that similar to Merck which had used LNPs internally as a disease interrogation and target validation tool, but not for commercial development before- even before GalNAc had come to prominence- J&J may view LUNAR-RNAi as a relatively speedy, but inexpensive way to test RNAi for its potential as a backbone therapy in HBV.  If it likes what it sees, watch out for the real deal with Dicerna or Arrowhead.  

HBV RNAi 2.0

Gene knockdown, in particular RNAi and RNaseH antisense, holds great promise in the treatment of hepatitis B viral infection.  It is currently the only practical means to potently inhibit all viral gene products*.  It therefore is poised to become a cornerstone of future treatment regimens aiming at functionally curing HBV, an infection predisposing more than 200 million patients worldwide currently to liver failure and cancer.

Arrowhead- lessons learned

Unfortunately, the field took a big hit last year when HBV RNAi trailblazer Arrowhead Pharmaceuticals had to abandon its efforts due to preclinical toxicity resulting from its particular approach to releasing the RNAi triggers into the target cell cytoplasm (monkey deaths due to the DPC).

Nonetheless, after more than a dozen trials in WoMan, the company had learned a great deal about HBV and how to best tackle it by RNAi.  Chief among those lessons were the observations that RNAi can suppress viral genes, most notably the surface antigens HBsAg by sometimes more than 2-3 logs.  Moreover, in HBe-antigen negative and those HBe-antigen positive patients previously exposed to polymerase inhibitors (‘nukes’), Arrowhead painfully found that most HBsAg is derived from host genomically integrated HBV.  Consequently, RNAi trigger target sites placed downstream of the HBsAg ORF may be lost and RNAi rendered futile (ARC520àARC521 transition). 

Finally, consistent with the experience with nukes and interferons, it appears that RNAi treatment success (functional cure) should follow complex viral and host immune dynamics and while intriguing changes were observed in the clinic with ARC520/1 (e.g. new lower baselines following treatment cessation), it remains unclear how long an RNAi agent would have to be given.  This has implications for whether intravenous routes of administrations are practical or not.

The competition

Arrowhead Pharmaceuticals, however, has not been the only RNAi game in town developing HBV therapeutics.  Its main competitor in terms of scientific prowess has been Arbutus Biopharma (renamed from Tekmira after biotech wonder boy Vivek Ramaswamy of Axovant fame spectacularly raided the company in 2015).  Its lead RNAi candidate ARB-1467 comprises of 3 RNAi triggers which are formulated in lipids (LNP) and is given intravenously alongside steroids.

While I like the 3-trigger strategy for pangenotypic coverage and for minimizing the risk of the virus developing drug resistance (including by genomic integration), the more cumbersome intravenous route of administration- now reduced to short 2-week intervals in an effort to increase potency- and the steroids makes ARB-1467 uncompetitive in a world of more potent and less frequent simple subcutaneous competition.  The use of immune suppressive steroids, of course, in HBV patients is a dicey proposition and would also seem to run counter to the ultimate aim of achieving immune control of the virus.

Unless it turns out to promote a functional cure along with other agents in short order, say less than 6-12 months, ARB-1467 will likely end up as a science project without much clinical impact.

RNAi powerhouse Alnylam Pharmaceuticals meanwhile is the third RNAi company that has begun clinical development of an HBV RNAi agent.  Importantly, it has been the first company using a simple subcutaneous GalNAc-conjugate format, therefore positioning it to be useful even when more prolonged treatment will turn out to be necessary.

After review of the program, however, it appears that the company prematurely rushed the single trigger ALN-HBV into the clinic without thinking too much about resistance issues.  To start with, ~2% of tested HBV genotypes have mismatches with the trigger that mitigate targeting efficiency.  As a single trigger candidate, ALN-HBV will also have to be given alongside highly potent replication inhibitors (nukes) as one can easily see how ALN-HBV resistant genotypes would otherwise eventually take over.

ALN-HBV moreover targets a site downstream of the HBsAg ORF, around the DR2 repeat element with marks the integration hotspot that has bedeviled ARC-520 before.  While Alnylam has been going around claiming ALN-HBV doesn’t suffer from ARC-520-type issues, I would challenge them with two points:

1)     under selection pressure by ALN-HBV to maintain HBsAg expression and thus evade host immune detection, the virus may ‘choose’ to break up upstream the ALN-HBV target site without affecting the HBsAg ORF; 

2)      more troublesome, closer inspection of the very paper Alnylam points to for making its claim (Jiang et al. Genome Research 22: 593) and which analyzes HBV integration hotspots, shows that ~40% of DNA break points appear to be upstream of the ALN-HBV target site (compare ‘position 1600’ below).      

One can therefore easily see why the project leader behind ALN-HBV, Laura Sepp-Lorenzino, has recently left the company to join Vertex Pharmaceuticals.  One has to get the impression that ALN-HBV, just like ALN-GO1 have only been rushed to the fore as a front in order to keep a lid on their competition by creating doubt about the ability of Arrowhead Pharmaceuticals and Dicerna, respectively, to compete with juggernaut Alnylam. 

Thrilled to join @VertexPharma as Head of Nucleic Acid Therapies!!!

— Laura Sepp-Lorenzino (@LauraSepplore) September 23, 2017

 

It is yet another lesson that in drug development, a detailed understanding of the disease is as important as the technology used to tackle it.  Half-hearted side projects typically lead nowhere.

Lastly, I would be remiss if I did not mention the RNaseH antisense efforts by Ionis along with partner GSK, and those of Roche.  Ionis/GSK are not only developing an unconjugated fully phosphorothioated antisense molecule, which I believe has little chance of competing in the market due to predictable safety and potency issues, but also a more interesting GalNAc-conjugate version (IONIS-HBV-LRx).  Although I currently see RNAi ahead of antisense in gene knockdown in hepatocytes (potency, frequency of administration, and safety), the GalNAc-conjugate version potentially has the advantage of also being able to access the pregenomic RNA directly, while direct pgRNA cleavage by RNAi of this non-mRNA remains to be shown.  My prediction is that  while RNAi can to some degree access pgRNA, this is not as effective compared to its cleaving mRNA.  What all of this means biologically remains to be seen.

Arrowhead HBV RNAi 2.0

Therefore, after all the drama and competitive noise, Arrowhead is poised to recapture the HBV RNAi lead with its new GalNAc-based candidate.  ARO-HBV is poised to enter the clinic in the first half of 2018.   It is subcutaneously administered and involves 2 RNAi triggers that are claimed to cover the viral resistance bases, including HBsAg derived from genomically integrated HBV.

The company expects the agent to be used once a month or less frequently, an attribute valuable should functional cures take longer to emerge.

Given knowledge leadership in HBV gene knockdown and prior practical experience, Arrowhead should also be able to navigate through the HBV clinical development maze faster than its competition.  As can be seen from its resurging stock price, this view is also shared by an increasing number of investors. 

Arrowhead has paid for taking some short-cuts when it was compelled to push ARC-520 into the clinic to give it a shot of becoming a serious player in RNAi before it ran out of capital.  It took some risks and failed, but that failure could well be the soil from which future success will emerge. 

Disclosure: long Arrowhead Pharmaceuticals

 

 

 

 

 

 

* it is unclear whether RNAi can directly cleave pregenomic RNA, whereas RNaseH antisense should be able to do that.

HBsAg Rules at International Liver Congress

Now that the HBV world has gathered extensive clinical experience with interferons and polymerase inhibitors (NUCs) and with the resolve to finally find a cure for a serious disease afflicting hundreds of millions worldwide, the hepatitis B surface antigen (HBsAg) has become recognized as the key determinant for treatment outcome.  This is being confirmed by trial after trial investigating combining the actions of both NUCs and interferons, either one after the other or together at once.

Some of these studies were presented at the International Liver Congress last week in Vienna (ILC2015).  Emerging from them are actionable HBsAg rules which can predict fairly well whether a patient will eventually seroconvert to (or at least lose) HBsAg.  No matter the excitement around CRISPR technologies, HBsAg seroconversion remains the gold standard outcome in HBV treatment in the foreseeable future.

These rules can be divided into pre- and post-IFN treatment onset.

In the pre-IFN setting, it is those patients that have below ~500 IU/ml serum HBsAg as a result of NUC treatment that will most likely respond to interferon treatment/immune stimulation with s-antigen seroconversion (see earlier blog entry).  Since NUCs alone hardly do anything to promote s-antigen seroconversion despite its dramatic lowering of viral HBV titers, it appears to be their slow impact on HBsAg levels ( 0.1 log per year HBsAg reduction) that has the synergistic effect with interferon: with HBsAg lowering you take off the foot on the immune brake, with interferon you step on the immmune gas pedal.

As such, HBsAg knockdown by RNA(i) Therapeutics would seem to do the same for interferons as NUCs do, only in a more rapid and potent manner.  Of course, both could be used concurrently as a run-in to IFN treatment.

However, once on IFNs (post-IFN onset), it is the relative HBsAg decline that has high positive predictive value in prognosticating who will seroconvert.  Of note, the HBsAg decline comes before any adaptive immunity can be detected.  This supports that HBsAg decline in itself contributes to seroconversion rather than it being a mere correlation.  In that setting, it is a 1 log decline in HBsAg the first few weeks after IFN treatment onset that separates the winners from the losers. 

It is uncertain to me, however, whether 1 log is a precondition to s-antigen seroconversion as the non-responders do not even come close to that (maybe 0.3log).  It is therefore possible that anything that pushes HBsAg below say -0.3-0.5log could have a dramatic effect on s-antigen seroconversion rates.

An RNAi Therapeutic for HBV used simultaneously with IFNs may therefore aim at helping IFNs to get to the  0.5-1log reduction threshold, and rapidly at that.

Ergo, there are now a number of obvious strategies that one can apply regarding the use of RNAi Therapeutics in HBV with various knockdown goals, both absolute and relative.  The exact strategy would depend on how the RNA agent is combined with polymerase inhibition/NUCs or immune stimulation. 

While a number of other HBV targets were reported at the conference such as core assembly and entry inhibitors, HBsAg (and HBV mRNA knockdown in general) lowering remains the most distinguished and the mechanism predicted to be most synergistic to existing treatment approaches.  As combination treatment is strongly predicted to be the future of HBV, HBsAg lowering should become a pillar of those treatment regimes.

Disclosure: long ARWR, looking for lower entry in TKMR.

Absolute HBsAg Levels, Not Percent Decline May Be Goal of HBV RNAi

I just walked into an early morning session at the International Liver Congress in Vienna and may have learned the most important nugget of information regarding RNAi treatment for HBV.

During the discussion in the ‘Banishing B’ session, Dr. Joerg Petersen referred to clinical analyses to be presented this Saturday showing that patients who achieve HBsAg levels of less than 500, or even better 200 IU/ml and then are given an interferon have a much better chance of eventually losing HBsAg, i.e. being functionally cured, than those that do not.

Dr. Petersen has been involved in clinical studies combining nukes and an interferon, and data presented at last year’s American Liver meeting (AASLD) showed that 9% treated with the combination for 1 year lost HBsAg in the year following combination therapy compared to just 2.8% receiving interferon alone.

Note that currently only interferons are thought to give you a chance of functionally curing HBV by medication and that HBsAg seroconversion attributed to interferon treatment may occur in the years after cessation of interferon therapy.  It will therefore be important to see whether this increase in seroconversion with combination treatment continues to hold up in subsequent years. The nukes are ‘only’ thought to protect the liver from the ongoing damage from HBV replication and may have to be given indefinitely.

I am not sure whether the new insight comes from a fresh clinical study or are the result of a more detailed subgroup analysis of the previous study.  Regardless, it hammers home a message that can be heard again and again, even more so in Vienna this year than at the London meeting last year: it is all about HBsAg lowering.

Implications for HBV RNAi

The implications of the new analysis for RNAi approaches for the treatment of HBV is obvious: use RNAi to get HBsAg below the threshold. In other words, it may be less about getting a magical 1log knockdown, but more about getting patients below 500IU/ml. 

For this, Dr. Petersen recommended using 2 nukes so that the tiny and very slow HBsAg declines observed on nukes continue ( < 0.1 log per year). With RNAi agents, you would likely achieve this goal for a patient with an HBsAg at baseline of 1000IU/ml within a month, even with a single 2mg/kg dose of ARC520 from Arrowhead Research as reported last year. 

The absolute knockdown potency of an RNAi agent would determine which fraction of the HBV population fall within this sweet spot. With a 1log knockdown e.g. you could start RNAi with patients with as much as 5000IU/ml.

For the clinical development of RNAi agents for HBV, the first step will be to determine the HBsAg decline on a background of nukes (just what Arrowhead is doing right now).  For pivotal trials, an immunostimulatory agent such as an interferon should be added to the nukeà RNAi/nuke treatment regimen to finish off the virus.

Stay tuned to learn about the fold benefit of HBV cures in patients falling below the 500IU/ml threshold, and the 3-4mg/kg single-dose results for ARC520 from Arrowhead Research to be reported later this quarter (note to Arrowhead PR department: next Monday may be a good time to do so).

Tekmira Merges to Create HBV Powerhouse as ex-Pharmasset Geniuses Seek an Encore

Last night, Tekmira startled the RNA Therapeutics world by announcing that they would combine with OnCore Biopharma in a merger-of-equals to create the HBV drug development powerhouse.  With eight investigational HBV assets in the pipeline, this model follows the HCV space where combination therapies and companies with a single-minded focus on HCV were able to create tremendous shareholder and patient value.

Most often cited here is Pharmasset which gave Gilead HCV wonderdrug Sovaldi for an at the time (2011) unprecedented $11B.  Of note, OnCore Biopharma was founded by ex-Pharmasset people, including the inventor of Sovaldi.

This also makes it clear that despite paying lip service to the combined Tekmira to continue to value their other liposomal RNA Therapeutics assets ex TKM-HBV1/2, it is a good guess that the RNA Therapeutics platform will not have a long life in the merged company.  This is also because with $100M in cash, the company will have to look for ways to raise capital, some of it in a non-dilutive manner.

Combination and speed

Before the merger, OnCore had already started sweeping up a number of HBV-related assets intended to tackle chronic HBV infections at multiple stages: 1) replication and gene expression; 2) promoting, by stimulating and de-repressing, an immune response against the virus; and 3) even removing cccDNA, thus aiming not only at an already extremely valuable ‘functional cure’, but complete cure.

It is likely that only a multi-pronged approach will be able to achieve that.  The two RNAi candidates by Tekmira which have just entered the clinic are expected to form the cornerstone of that since they target ALL the viral genes.  Moreover, in the challenging chimeric mouse model, TKM-HBV1/2 had an unexpected impact on cccDNA abundance. 

The fact that TKM-HBV is administered intravenously is acceptable for this disease as long as a (functional) cure is achieved after a finite treatment period which, of course, is the goal. By contrast, the other assets contributed by OnCore are largely, if not all oral, including agents designed to inhibit immunosuppressant HBsAg secretion. 

Unlike TKM-HBV, these are at the pre-clinical stage, at least regarding their use for chronic HBV (the TLR9 agonist has already been tested in humans for non-HBV applications).  It is expected that many of them will enter the clinic this or next year. 

Regarding clinical development, the initial goal is to establish the safety of these agents individually before combining members from the three different classes pairwise and in triplicate in phase II.

The fact that all modalities are now under one roof will also greatly accelerate development timelines as, again in analogy to the HCV experience, it would otherwise have made necessary protracted partnering negotiations, sometimes with direct competitors.

Merger a good deal for Tekmira shareholders

Although I bemoan the loss of Tekmira as an RNA Therapeutics platform company, creating the strongest drug developer in the hot HBV space is the more attractive alternative also given the importance of TKM-HBV to Tekmira even before the merger. 

Accordingly, it is more likely that this setup will yield Pharmasset-type returns (say 10x in 3 years), e.g. following an acquisition after showing >40% cure rates in phase IIb, compared to a more balanced RNA Therapeutics platform play which has faced considerable competition from increasingly potent and more convenient technologies. 

Congrats to Tekmira management and Directors. The seeming investor relations breakdown recently has now been explained. Well played!

Tekmira Presents Solid Pre-clinical Package for Upcoming HBV Clinical Candidate

Yesterday, Tekmira Pharmaceuticals presented the long-anticipated RNAi candidate for the treatment of HBV infection at the Annual Oligonucleotide Therapeutics Society conference (click here for the corresponding slide deck).  Accordingly, it was shown that TKM-HBV mediated solid knockdown of all HBV viral RNAs and proteins.  This included data in the challenging (and costly) mouse model carrying humanized livers (comprised of a mixture of mouse and human liver cells) competent of supporting the full HBV viral life-cycle.

In these mouse models, repeat doses of 0.3mg/kg resulted in ~90% reductions of both the critical HBV surface antigen (HBsAg) and viral DNA.  This may be an underestimate of the true potency of TKM-HBV as suggested by data targeting the human apoB gene in this model.  These suggested (although not proved) that it is much more difficult to achieve potent knockdowns of genes expressed in the human liver cells as compared to genes expressed in the neighbouring mouse cells of the same liver: around 10x the amount of RNAi trigger was required to achieve comparable knockdowns for the human ApoB gene relative to the mouse ApoB gene.

Based on these results, I expect an approx. ~85% knockdown of HBsAg in single-dose studies at doses that I conservatively expect to be very well tolerated (~0.2mg/kg).  As indicated by the recent clinical results with ALN-TTR02 and chimpanzee studies by Alnylam/Merck, both of which involved Tekmira's SNALP LNP delivery technology, these knockdown numbers are likely to improve with more prolonged repeat administration.

In case that Tekmira is able to safely dose escalate to higher dosages, say 0.5mg/kg, significantly more potent knockdowns can be expected.  One ought to, however, keep in mind that such higher doses are not necessarily supported by the clinical history of SNALP LNP which indicates that innate immune stimulations could become an issue around 0.3mg/kg. On the other hand, the otherwise conservative Tekmira management has been surprisingly optimistic as to 3rd gen SNALP LNP-enabled TKM-HBV being devoid of innate immunostimulatory activity.

Comparison with Arrowhead's ARC520

The results support the notion that Tekmira's HBV candidate will be more potent than Arrowhead's competing HBV candidate, ARC520.  However, there are many uncertainties in making such a prediction, most importantly the dose levels found to be safe and well tolerated in the clinical studies.  To wit, ARC520 is still dose-escalating and so far has exhibited a very good safety profile meaning that 90% (1log)-type knockdowns are well within reach, especially with repeat dosing.

Beyond potency, it should be noted that TKM-HBV comprises of 3 different RNAi triggers, both to cover the vast majority of viral sequence variation and to minimize the potential of breeding drug resistance.  To my surprise, such resistance mutations were observed in a woodchuck model that Tekmira conducted together with HBV powerhouse Bristol Myers Squibbs.

Oh, BMS? You can bet that should RNAi Therapeutics be able to meaningfully increase HBV cure rates from the low bar set by current standard of care (~15% with ill-tolerated immune stimulants), not only will BMS, but also the likes of Gilead be very interested to swoop in to pick up one or both of these compounds and/or companies.

An IND filing for TKM-HBV is on track for year-end 2014 with first drug administrations in early 2015.

Disclosure: I am long both TKMR and ARWR.