Roger Pomerantz
Analyst · Canaccord
Thanks, Carlo. And thank you all for joining us. Seres has made excellent progress in our efforts to advance our microbiome pipeline. Seres is focused on developing new therapeutics for serious human diseases were dysbiosis of the gastrointestinal microbiome is thought to play a central role. We believe that microbiome therapeutics has the potential to address multiple disease states and our R&D efforts target therapeutic areas where compelling clinical and/or preclinical data indicate that the microbiome is important, such as infectious diseases, metabolic diseases and inflammatory and immune diseases, including immuno-oncology. On today's call, I will provide an update on Seres' substantial progress in advancing our pipeline, including most notably the positive data we obtained with SER-287. So, let's begin with SER-287. SER-287 is an orally-administered, biologically-sourced drug candidate comprised of a wide array of species of natural, commensal bacteria in spore form that reside in the healthy human gastrointestinal tract. Our advanced manufacturing process isolates and purifies the spore for action from human donor material. These hardy bacterial spores are metabolically inactive until they reach the germination conditions of the colon where they transform into a physiologically active state. Both preclinical and clinical studies have indicated that fecal microbiota transplants, or FMPs, would benefit ulcerative colitis patients. Repetitive fecal microbiota transplants have been evaluated in at least four randomized, placebo-controlled studies of patients with ulcerative colitis and clinical efficacy was demonstrated. This shows that modulation of the microbiome can lead to clinical remission and provide strong clinical evidence supporting the role of the microbiome in ulcerative colitis. Last month, we announced positive results from the SER-287 Phase Ib study, a randomized, double-blind, placebo-controlled, multiple dose trial in 58 subjects, with active mild to moderate ulcerative colitis, who were failing their standard therapy. As seen on slide four, subjects were assigned to one of three SER-287 treatment arms or a placebo arm. The SER-287 arms included a daily dosing arm with vancomycin pretreatment, a weekly dosing arm and a weekly dosing arm with vancomycin pretreatment. The study's endpoints are listed on slide five. Total modified Mayo scores were collected in all study subjects at a pretreatment baseline and at the end of treatment. The Mayo score is evaluated based on measures of stool frequency, rectal bleeding, a physician's global assessment, and endoscopic evaluation. In order to maximize the objectivity of the endoscopic evaluation, all endoscopy recordings were assessed by a blinded central reader. Two prespecified, intend-to-treat statistical methods were used to analyze SER-287 Phase Ib efficacy outcomes. These are illustrated on slide six. The first method analyzed all observed data and the second analyzed missing data counted as failure. Analyses from each approach demonstrated that SER-287 administration resulted in a dose-dependent improvement of both clinical remission rates and endoscopic scores. The highest efficacy was observed in the vancomycin pretreatment daily SER-287 arm of the study. As seen on slide seven, based on an intend-to-treat observed data analysis in this arm, 40% or 6 of 15 patients reached remission, while only 10% or 1 of 10 patients achieved this endpoint in the placebo group. The single placebo patient who achieved remission actually had a flare during the study and received steroids, a protocol violation. However, because this patient was in clinical remission at the end of the study, the prespecified observed data approach counted the patient as a remission even though they violated protocol. Now, moving to slide eight, under the other prespecified method, missing data counted as failure. Again, 40% or 6 of 15 subjects reached clinical remission. But now compared to 0%, zero of 11 in the placebo group. Even in this rather modestly-sized initial study, this result was statistically significant with a p value of 0.0237. In addition to the clinical remission endpoint, we also saw compelling treatment effects of a similar magnitude on direct endoscopic measures in both statistical analyses. I also wanted to discuss the clinical response data observed in the study. We observed high clinical response placebo rates that were not differentiated from the rates in the 287 treatment arms. Based on the drawbacks of clinical response endpoint, the FDA's latest regulatory guidance from August 2016 now recommends the use of clinical remission and not clinical response as the primary endpoint in all registrational studies for UC. Clinical response is a subjective endpoint and prone to high variability. As such, high placebo rates in clinical response have been clearly demonstrated in several previous Phase II trials in UC with drugs using diverse mechanisms of action. We believe that response rates are very difficult to interpret in ulcerative colitis clinical studies, particularly when interpreting data from any modestly-sized study. Now, as part of the FDA's most recent guidance, modifications were made to the definition of clinical remission. These can be seen on slide nine. The new FDA guidance requires that for clinical remission to be achieved, a subject must have a zero score on both rectal bleeding and stool frequency Mayo subscores and a zero or one on the endoscopies subscore. Because this FDA new guidance was implemented after the SER-287 study was initiated, the statistical analyses defined in our protocol were based on the prior standards. We have, however, also analyzed our study results based on definition of clinical remission included in the new FDA guidance. These results can be seen on slides 10 and 11. When analyzed under the new FDA guidance, the SER-287 study efficacy results remain highly compelling. Indeed, the level of statistical significance associated with the endoscopic improvement endpoint for the SER-287 daily arm is increased when our data is analyzed per the new FDA guidance defining clinical remission. This improvement is seen when the data are analyzed with both the observed case analyses and the missing data counted as failure analyses. Interestingly, in the missing data counted as failure analyses using the new FDA guidance, both the clinical remission rates and the endoscopic improvement rates were statistically significant in this SER-287 daily arm. As previously mentioned, clinical response is not defined nor recommended as a primary endpoint under the new FDA guidance. Now, moving on to SER-287 safety. The SER-287 safety and tolerability profile was very favorable. Results demonstrated no imbalance in adverse events in the SER-287 treated patients as compared to the placebo arm and there were no drug-related serious adverse events associated with SER-287. Now, interestingly, we also observed that SER-287 subjects in the daily dosing arm experienced fewer GI-related adverse events than those treated with placebo. And we believe this represents an additional independent line of evidence pointing to a beneficial SER-287 impact on disease activity. If you are interested in additional information, I would point you to the detailed study results slides that are available on our website. We continue to look forward to additional important data from the SER-287 phase Ib study, including detailed microbiome analyses, histology and other biomarkers in the coming months. We believe these data could provide further insights into SER-287's mechanism of action and could help inform future 287 development efforts and the development of follow-on products, including our fully synthetic SER-301 program. Overall, we were very pleased with the SER-287 Phase Ib results. Our objective with SER-287 is to develop a highly effective, orally administered therapeutic option, which is importantly not immunosuppressive. Ulcerative colitis is a highly debilitating condition that is often refractory to all available treatments. There is a high need for new mechanistic approaches and it is our hope that SER-287 will provide an entirely novel mechanistic approach. We are now considering a development plan that maximizes SER-287. We intend to meet with the FDA to determine the optimal next steps for development once we obtain the remaining study data. Now, moving to our SER-109 program Phase III for patients with multiply recurrent C. diff infection. We have continued to make progress adding clinical sites and actively enrolling patients. We also recently obtained clinical trial application clearance from Health Canada and expect to have Canadian clinical active sites in the coming weeks. To remind you, SER-109 has received both breakthrough and orphan drug designations in the US and the FDA has demonstrated a deep interest in the microbiome as an important emerging therapeutic modality. Based on our discussions with the FDA, we expect that, with persuasive efficacy and safety results from this single Phase III study, Seres would be able to file SER-109 for regulatory approval. Seres has also continued to make progress driving the SER-262 Phase Ib study forward in patients with primary C. diff infection. SER-262 study is notable that it is the first-ever clinical trial to evaluate a rationally designed, multi-strain, fermentation-generated microbiome therapeutic candidate. In this first-in-human, dose-ranging Phase Ib study, we are evaluating primarily safety and tolerability of SER-262 and also pharmacokinetics and pharmacodynamics as measured by microbiome changes. We will also evaluate clinical efficacy trends across the dose cohorts. We anticipate obtaining SER-262 Phase Ib top line study results in early 2018. In addition to our three clinical stage programs, we continue to make progress in our earlier-stage R&D efforts, including those in inflammatory diseases, metabolic diseases, liver diseases and immuno-oncology. Seres has just been awarded a grant of up to $5.6 million from CARB-X that will support the advancement of our preclinical SER-155 program. CARB-X is a public-private partnership devoted to advancing novel antibacterial therapeutic approaches. We are developing SER-155, a rationally designed bacterial composition to reduce rates of both serious infections, as well as graft-versus-host disease in patients who receive either allogeneic stem cell or solid organ transplantation. The rationale supporting SER-155 is based on clinical data showing that patients with healthier, more diverse gastrointestinal microbiomes have better outcomes than those with more dysbiotic microbiomes. We will continue to finalize the composition of SER-155. And with the support of CARB-X funds, we intend to move this program into a clinical study. I'll now pass the call to Eric to review our recent financial performance.