Chris Garabedian
Analyst · JMP Securities
Thank you, Erin. Good afternoon, everyone and thank you for joining us. I’m pleased to provide you with an update and overview of our activities and accomplishments since our last call along with our financial performance in the first quarter of 2012. We reached a very important milestone in our DMD program this quarter. We announced on April 2 that our Phase llb study of Eteplirsen in Duchenne Muscular Dystrophy met its primary endpoint by demonstrating significant levels of novel dystrophin in treated patients after 24 weeks of Eteplirsen, our lead drug candidate for DMD compared to placebo patients.
This is also an important study for the muscular dystrophy community in that it is the first placebo controlled study to demonstrate that robust and consistent levels of dystrophin protein, the essential protein that Duchenne Muscular Dystrophy patients are lacking can be produced with drug therapy. We believe this provides tremendous promise to patients with DMD as we know that production of dystrophin is critical for healthy muscle function and may be the key component to slow or halt the progression of the disease.
As we announced on our call on April 2nd, the primary efficacy endpoint defined in our protocol and our statistical analysis plan was the increase of dystrophin positive fibers as a percentage of normal compared to baseline and then compared to our placebo group. We met our primary endpoint with a high degree of statistical significance with a p value of 0.002 at our 24 week time point in our 30 milligram per kilogram cohort.
We also achieved a higher level of dystrophin production than what we were anticipating, an average of more than 20% dystrophin positive fibers, or approximately 23% as a percentage of normal, a level that the medical literature would suggest should translate to favorable clinical outcomes and less progressive muscle degeneration and disease over time. This is based on animal models of Duchenne along with the known natural history of Becker’s Muscular Dystrophy and the levels of dystrophin that are seen in this milder form of muscular dystrophy.
Most importantly, we observed consistency across all of the patients in this cohort with a range of 15.9% to 29% of novel dystrophin fibers. To clarify, this is not a relative percentage increase but an increase in the percentage of absolute fibers identified as dystrophin positive or in other words, as a percentage of normal. In our previous study that only dosed Eteplirsen for 12 weeks at lower doses, we only observed 2 patients out of 19 that showed dystrophin positive fibers of 15% or greater while all of the patients were over 15% in this 24 week cohort.
Our biopsies that were taken after 12 weeks of Eteplirsen at the 50 milligram per kilogram level showed low and variable levels of dystrophin production which was consistent with the majority of patients in our previous study underscoring the need to dose beyond 12 weeks to get consistent and meaningful levels of dystrophin in the muscle. In the 4 patients on Eteplirsen that received biopsies after 24 weeks of treatment, the increases in dystrophin positive fibers seen by immunohistochemistry analysis were further verified by the increased overall dystrophin intensity per fiber calculated in the muscle samples of over 20% intensity per fiber on average. And, we had clear production of dystrophin protein overall as shown by western blot analysis.
Mechanism of action of Eteplirsen was also verified by RT-PCR in showing exon skipping on the muscle biopsy samples in this cohort as well. Importantly, proper molecular function of the newly created dystrophin was demonstrated in this study and a recent publication which showed that Eteplirsen induced dystrophin stimulated the correct localization and function of other components of the sarcoglycan and dystroglycan complexes such as alpha, beta, and gamma sarcoglycans, beta sarcoglycans and nNOS, neuronal nitric oxide synthase, key components that provide further evidence that the dystrophin that we’re producing is a functional dystrophin protein.
Another important objective of this study was to evaluate the safety profile of Eteplirsen. At doses that are the highest ever evaluated using our Morpholino drug chemistry, the safety profile of Eteplirsen at 24 weeks continues to show tremendous promise as a potentially safe drug for long term use. This is an important characteristic of a drug that might require lifelong treatment. Through 24 weeks of treatment there were no serious adverse events, no treatment related adverse events of any kind, and no treatment related changes detected on any safety laboratory parameters including several biomarkers of renal function.
The study also collected data on exploratory clinical outcomes over the course of 24 weeks and an analysis was conducted using the 6 minute walk test, the standard clinical endpoint that has been used in other DMD trials and has served as the basis for approval for drugs to treat other neuromuscular conditions. An exploratory analysis of performance on the 6 minute walk test comparing Eteplirsen treated patients versus placebo patients was conducted. However, the analysis was cofounded by 2 patients in the 30 milligram per kilogram cohort that showed rapidly progressive decline immediately after being enrolled in the study.
Specifically these 2 patients had the lowest baseline scores on the 6 minute walk test entering into the study, were both below 250 meters by week 4, and were the only boys who lost more than 50 meters by week 12. We now know, based on our dystrophin data that this is too early to expect a treatment affect. For these reasons we excluded these 2patients from our analysis.
Of the remaining patients, all of which were relatively stable across both treated and placebo cohorts, the Eteplirsen treated patients demonstrated a benefit of approximately 18 meters over 24 weeks. Importantly, these 6 Eteplirsen treated patients had an average decline of only 3.2 meters from baseline or less than 1% of their baseline scores, which we view as essentially no progression over this time point. However, the placebo patients had an average baseline decline of 21 meters over this same time frame.
While this was an exploratory analysis on a subset of patients and was not a statistically significant difference given the small sample size, it is an encouraging sign of a potential treatment affect as we await results at 48 weeks. To put this data in the appropriate context, several drugs have been approved on 6 minute walk test results that have shown a benefit of 25 to 30 meters over the course of one year to 18 months. If we double this treatment affect that we saw at 24 weeks, we believe we would have a meaningful level of clinical benefit at 48 weeks.
We are hopeful that we may see further separation between the 6 treated patients I’ve described and the 4 placebo patients at the 48 week time point. Even though the placebo patients are now on study drugs, we don’t expect they will generate meaningful levels of dystrophin until beyond 12 weeks of dosing and possibly up to 24 weeks. While we presume the 6 treated patients will all have levels above the 15% to 20% range as they enter into the next 24 weeks of the study.
This study which we have named Study 202 which is our extension study to the placebo controlled study, Study 201, continues to access the long term safety and efficacy of open label Eteplirsen. As a reminder, we now have 6 patients on 30 migs per kig per week and 6 patients on 50 migs per kig per week and we will have 48 weeks safety and efficacy data in 8 of these patients and 24 week data in 4 of the original placebo patients later this year.
We also have a third biopsy that will occur at the 48 week time point in the original treated patients and after 24 weeks of treatment in the original placebo patients who crossed over to study drugs. These biopsy data will be important to understand the steady state or potential plateau levels of dystrophin. This dystrophin data set will answer many questions including how much do dystrophin levels increase in the 30 milligram cohort between 24 and 48 weeks, how much more dystrophin is produced at 50 milligrams per kilogram at 48 weeks compared to 30 milligrams per kilogram.
In addition, we will have 24 week dystrophin data at 50 milligrams per kilogram for the first time from 2 of the original placebo patients and we will also have 2 additional patients with biopsies after 24 weeks of treatment at the 30 milligram per kilogram dose to compare to the previous cohorts where we showed robust and consistent levels of dystrophin production. We believe these additional biopsy results along with the additional long term clinical outcomes in safety will be useful in our discussion with the FDA as we discuss the fastest path towards approval.
We will plan to put the results from Study 201 and Study 202 along with our long term animal tox program results into a briefing document to request an end to Phase ll meeting with the FDA in the fourth quarter of this year. The purpose of that meeting with the FDA will be to discuss the design of our pivotal study including gaining feedback on the accessible endpoints for approval. We are still planning to initiate a larger confirmatory pivotal study for Eteplirsen in 2013.
One strategic shift since we unveiled our data set at the American Academy of Neurology is our willingness to broaden the type of strategic partnership on DMD that we will consider. With a robust proof of concept now in our lead program with Eteplirsen, we believe that this is highly reproducible across other exon skipping targets. We currently are showing good progress on our 2 collaborations on exon 45 and exon 50 drug candidates where we are receiving grants to support the IND enabling work to move these 2 candidates into clinical development.
We are also in discussions with granting authorities and foundations for the pursuit of other exon skipping drug candidates. A strategic partner that can bring more resources to bear on our broader DMD program can be a win-win for AVI and for the DMD community in that it may allow us to accelerate the development of other DMD drugs and towards an eventually class approval for our exon skipping drug platform. This will enable us to provide treatments for the broader group of DMD patients who can benefit from exon skipping drugs.
Now, I’ll turn our attention to our government sponsored infectious disease programs where we continue to advance our 2 drug candidates for the treatment of life threatening hemorrhagic fever viruses of the Ebola and Marburg. We continue to prepare for our multiple ascending dose or MAD studies in healthy volunteers for both drugs and we are looking forward to exploring multiple doses and potentially higher doses than the 9 milligrams per kilogram that we proved safe in single ascending dose studies.
This will help us understand and possibly widen the therapeutic window for not only our Ebola and Marburg drug candidates but for future applications against emerging viral and bacterial targets utilizing this same backbone chemistry. These MAD studies are still planned to start in the second half of this year.
We are currently in a study on our Ebola drug candidate where we are evaluating the active components of the drug as a single agent versus the combination drug AVI6002 that had been previously tested, similar to how we demonstrated that AVI7288 on a standalone basis for Marburg was efficacious as a single agent. We expect to announce top line results from this Ebola study looking at single agents components versus the combination in the coming weeks.
Lastly, on the corporate front, we announced the departure of Peter Linsley, our Chief Scientific Officer who has resigned from the company effective June 1. Peter was a tremendous help to me in reshaping our research efforts and priorities for our early drug discovery efforts and the research organization is left in a better position than where it was when he started at AVI.
As we announced last year, we had a reduction in staff in December that included members of our research organization and curtailed many of our non-essential research activities to focus more of our resources on our clinical stage programs. While I would have liked to have provided Peter with a larger research staff and budget, we were not able to pursue many of the research ideas that Peter had for our technology due to resource constraints. We are sad to see him leave and wish Peter the best as he determines what he will do after his departure from AVI.
That concludes my corporate update and with that I’ll turn it over to Mike Jacobsen who will give you a financial update for this quarter.