Mike Panzara
Analyst · Salim Syed with Mizuho
Thanks Chandra. The third quarter was very productive for our therapeutics discovery and development organizations. Falling onto Chandra’s introduction about progress with ADaR editing, I will start by describing our first therapeutics program evaluating AIMers as a potential treatment for AATD. I will then provide an update on where we are where with our three programs currently dosing in clinic and share why we believe our approach has positioned as well for success in the coming year. AATD is an inherited genetic disorder that is most commonly caused by a point mutation in the SERPINA1 gene, commonly knowns as the Z allele. This mutation leads to misfolding and aggregation of alpha-1 antitrypsin protein or Z-AAT in hepatocyte and a lack of functional AAT in circulation, which results in progressive lung damage, liver injury or both, eventually leading to end stage pulmonary and liver disease. As there are both loss of function and gain of function aspects this disease, RNA editing is uniquely suited to address all therapeutic goals of treatment. While there are multiple alternative approaches in development, each of these only address a subset of the details. With AIMers, we aim to correct the SERPINA1 mRNA to restore circulating functional wild type alpha-1 antitrypsin protein or M -AAT to protect the lungs, and reduce the Z-AAT protein aggregation in liver, all while retaining the unique physiological regulation of M-AAT. With our gamma conjugated stereo pure AIMers, we anticipate replacing chronic IV AAT protein augmentation therapy with a subcutaneously administered treatment. The number of patients that could benefit from such a therapy is sizable, with approximately 200,000 people in the US and EU that are homozygous for the PiZZ mutations, a genotype with the highest risk of lung and liver disease. In initial experiments prior to optimization we evaluated labelled SA1-4 in-vivo to assess editing and protein restoration over the course of 35 days. Following three subcutaneous doses, we were encouraged by these initial results as they approached therapeutic threshold targeted by augmentation therapy and levels in patients carrying the PiMZ genotype, a subtype known for having a lower risk of symptomatic disease. The RNA editing achieved resulted in a threefold increase in circulating AAT as compared to PBS control, a therapeutically meaningful increase. Further, the increases in AAT protein were greater than or equal to three-fold over PBS control lasting out to 35 days. To evaluate the specificity of the SA1- or GalNAc AIMer we performed our RNAC. On the left, you can see total sequence coverage across the entire SERPINA1 transcript for the AIMer treated samples. The percentage of unedited T and edited C reads are indicated for each group. Editing is only detected at the intended on target sequence in the SERPINA1 transcript. Thus the protein being produced using this approach is truly wild type M-AAT protein. This also confirms that there is no editing of bystander residues, as has been seen the DNA targeting approaches. Furthermore, to assess off-target editing for the whole transcriptome, we apply the mutation calling software to search at its sites. From this analysis, we observed nominal off-target editing across the transcriptome. Sites where potential off-target editing occurred had either lower read coverage in the analysis or a credit low percentage of less than 10% indicating that these are rare events. Thus in both analyses, we find a high percentage of editing that is specific for the target site in the SERPINA1 transcript. Recently, we shared our ability to use PRISM chemistry to optimize AATD AIMers to drive editing efficiencies of approximately 50% along with protein restoration, well above the therapeutic threshold, a four fold increase in total AAT as shown here with AIMer SA1-5. We continue to evaluate tolerability of potential candidates, as well as PK/PD profile, durability, and the ability to reduce Z-AAT protein aggregates and pathology in the liver, as we move towards identifying a development candidate, which is inspected in 2022. Turning to our ongoing clinical programs, in the third quarter, we've dosed initial patients in three clinical trials. These include our FOCUS-C9 clinical trial evaluating WVE-004 for patients with C9orf72, associated ALS and FTD. Our select HD clinical trial, evaluating WVE-003 for patients with HD with SNP3 genotype in association with their CAG expansion, and an open label clinical trial, evaluating WVE-N531 for patients with DMD mutations and amenable to Exon 53 skipping. All three of these candidates contained PN Backbone modification. The approach taken with our clinical and preclinical candidates built upon our own experiences along with innovations from the PRISM platform to design CNS candidates that promise to be distinct from others in the fields. The approach is illustrated in three columns showing the elements that we believe are key to the success of our emerging CNS portfolio. It begins with capabilities of PRISM at its core, and an increased understanding of the factors influencing the pharmacology of our molecules, along with the availability of in vivo systems to better understand PK/PD relationships to predict human dosing. Then, by leveraging proprietary chemistry modifications in the context of the ability to control stereochemistry, we can now rationally design candidates, optimizing for widespread tissue distribution target engagement with the potential for a favorable tolerability profile. Finally, careful selection of relevant biomarkers, other endpoints in patient population in the context of adaptive study designs that allow for real time adjustment of dose level and frequency, position us well to reduce risk and drive rapid decision making. Here, I would like to walk through an example of these principles and practice, highlighting the ongoing preclinical work with a stereopure ASO designed with PN backbone chemistry modifications targeting an undisclosed CNS target. As part of the optimization process, we developed several stereopure isomers with identical sequences, but differing stereochemistry with and without PN modifications. What this illustrates is the clear advantage of the isomer with the PN versus one without in terms of distribution of the ASO throughout the CNS tissues one month after a single intravitreal dose. Slide 30 shows the impact in terms of target engagement and tolerability of these different designs. Isomer 3 is the compounds shown on the previous slide. In these experiments, we assess target engagement in mice during the screening process, as compared with two other isomers all containing PN Backbone modifications. On the left hand side of the slide, you can easily see that robust target engagement was demonstrated with all three isomers, including isomer 3. However, as you can see on the right hand side of the slide, one of the three compounds, isomer 2 having dramatic different tolerability profile, with significant body weight loss over the observation period, despite being the same sequence as the other two. These data clearly demonstrate the optimization of sequence, backbone modifications, chemistry and stereochemistry must be an essential component of any drug discovery and development effort, if the promise of these important genetic medicines is to be fully realized. As we think about the path of our current programs to clinic, demonstrating target engagement and relevant preclinical models is core to understanding our -- core to our development. These data allow us to model the likely pharmacologically active dose in humans, guiding dose selection in our initial clinical trials. So, WVE-004 and 003 have robust effects and relevant models allowing us to start studies at dose levels predicted to engage target and proceed through the dose selection process considering these data and the human data collected along the way. First with 004, shown on the top of slide 31, two ICV doses administer seven days apart resulted in a profound reduction in poly-GP in the spinal cord and cortex. This reduction persisted for at least six months corresponding to sustain tissue concentrations 004 over this time period, highlighting the PK and PD effects of the stereopure containing compounds. Further the effects were highly specific leaving C9orf72 protein unaffected, which is important for normal regulation, normal function in the immune system. To our knowledge, this promising profile is unique amongst other C9 targeting compounds under development, including those in clinics. With 003 designed to selectively target mutant Huntington preserve the healthy or wild type HTT protein, we have shown the ability to lower mutant HTT both in vitro and in vivo with a clear dose effect. The data shown at the bottom of slide 31, including in vitro data and IPSC neurons demonstrating specificity for mutant HTT and preservation of wild-type. The back HD model used to demonstrate on target activity of 003 is somewhat limited in that, it contains multiple copies of the mutant HTT gene, some of which do not have the snip 3 variants. Nonetheless, we observed potent and durable knockdown and mutant Huntingtin in the striatum out to 12 weeks with a similar effect in the cortex. These data makes us excited about the potential for 003 in HD, where there remains a high unmet need for effective treatments. Moving on to WVE-N531, our first PN modify clinical candidate to be administered systemically. As also, our first -- it's also the first splicing candidate and it will provide insight into the ability of PN modifications to enhance access to dystrophic muscle and restore functional dystrophin expression. We are optimistic about this program given the compelling preclinical data comparing systemically administered PN modified exon skipping oligonucleotide with oligonucleotides only containing PS and PO modifications. The PN modified oligonucleotide lead to rescue of this rapidly progressive phenotype with an increase in dystrophin production and keep tissues including skeletal muscle parts and diaphragm. In closing, our current focus on advancing -- is on advancing ongoing clinical trial to evaluate translation of these promising preclinical datasets. To do this, we are using innovative trial designs that include multiple biomarkers and indicates independent committee reviews to potentially accelerate time to proof of concepts. We expect to generate data through 2022 across all three of these trials to enable decision making next year. I will now turn the call over to Kyle Moran, our CFO. Kyle?