Roger Pomerantz
Analyst · Bank of America
Thanks, Carlo, and thank you all for joining us. Seres continues to make strong progress as we work to develop an entirely new field of medicine using bacteria to treat disease. We are advancing our microbiome therapeutics platform to develop a novel class of biologically active drugs designed to treat serious human diseases by restoring the function of a dysbiotic microbiome where the natural state of bacterial diversity is imbalanced. Seres is specifically focused on serious human diseases where dysbiosis in the gastrointestinal tract is thought to play a key role. Seres is the pioneer and leader in this new microbiome field, and we have continued to advance our understanding of the underlying new science with the goal of developing innovative novel therapeutics. We believe that microbiome therapeutics have the potential to address multiple serious and -- diseases and our R&D efforts target three therapeutic areas: infectious diseases, inflammatory and immune diseases and metabolic diseases. On today's conference call, I will provide an update on the progress we've made preparing for the initiation of a new clinical study of SER-109, our lead therapeutic candidate for patients with multiply recurrent C. diff infection. I will also provide an update on our other clinical development-stage microbiome therapeutic candidates: SER-262 for primary C. diff infection; and SER-287 for ulcerative colitis in patients who are failing first-line therapies. Let's begin with SER-109 and recurrent C. diff infection. SER-109 is a biologically sourced, highly purified microbiome therapeutic candidate containing a consortia of bacterial spores found in healthy individuals. Our objective with SER-109 is to develop a new, convenient, effective and safe approach to treat patients experiencing multiple recurrences of C. diff infection. Today's standard of care for treating a C. diff infection is treatment solely with antibiotics. While antibiotics are often able to treat the acute C. diff infection, antibiotics also further disrupt the normal microbiome, resulting in a higher risk of further recurrence of this disease. Our therapeutic objective with SER-109 microbiome therapy is to catalyze repair toward a more healthy microbiome immediately following antibiotic use, meaningfully reducing the risk of a C. diff recurrence. We believe that SER-109 could represent a clinically important improvement over the limited treatment options available today for these patients. We have made excellent progress with our SER-109 program in recent months. At last month's European Congress of Clinical Microbiology and Infectious Diseases, our Chief Medical Officer, Dr. Shelley Trucksis, delivered an invited oral presentation discussing our learnings from prior SER-109 clinical development efforts. Our prior SER-109 clinical studies provide key biological and clinical data that we believe have meaningfully advanced our understanding of recurrent C. diff infection and the mechanisms of our microbiome therapeutic drug candidate. These data also provide Seres with important insights that inform our future development efforts. In March, we announced that we had completed a highly successful Type B meeting regarding the SER-109 program with the FDA. In our FDA dialogue, we reviewed detailed scientific and clinical data related to the program and our plans for a new SER-109 clinical study, ECOSPOR III. We have been very pleased with the level of engagement and the specific feedback we received from the FDA. The FDA has demonstrated significant interest in the microbiome as an emerging therapeutic modality, and I will remind you that SER-109 has both breakthrough and orphan-drug designations from the agency. Regarding the SER-109 specific feedback we obtained, importantly, the FDA agreed that our new study, ECOSPOR III, may qualify as a pivotal study with the achievement of a persuasive clinical effect and addressing FDA requirements, including clinical and statistical factors and adequately sized safety database and certain CMC parameters. ECOSPOR III is planned to include approximately 320 patients with multiply recurrent C. diff infection randomized 1:1 between SER-109 and placebo. The size of the study was driven both by assumptions regarding SER-109 efficacy and study powering as well as our desire to obtain an adequate safety database. All ECOSPOR III study subjects will be treated with standard-of-care antibiotics to address the qualifying acute C. diff infection, and subjects will then receive either SER-109 or placebo. ECOSPOR III will evaluate patients for 24 weeks, and the primary endpoint will compare the C. diff recurrence rate in subjects who received SER-109 versus placebos at up to 8 weeks after dosing. We have obtained several important learnings from our previous SER-109 development efforts that we will apply to ECOSPOR III. Diagnosis of recurrent C. diff infection, both at study entry and for primary endpoint analysis, will be confirmed by C. diff cytotoxin assays. We believe that the use of C. diff cytotoxin assays in the study will ensure that patients entering the study are truly experiencing an active C. diff recurrence. We also believe that use of the C. diff cytotoxin assay will increase the accuracy of in-study recurrence diagnosis for both subjects in the treatment and placebo arms. Patients in the ECOSPOR III SER-109 arm will receive a total treatment dose that is approximately tenfold higher than the SER-109 dose used in the prior Phase II study. The dose of SER-109 in ECOSPOR III will be administered over 3 consecutive days. We expect, based on our previous microbiome data sets in humans, that administration of SER-109 at this higher dose and over multiple days will support more rapid engraftment of SER-109 after antibiotic therapy, thereby reducing the risk of C. diff recurrence. Overall, we believe that changes implemented for ECOSPOR III will increase the study probability of success and expand the degree of efficacy we expect to see in SER-109-treated patients versus placebo. We have been making excellent headway preparing for the initiation of ECOSPOR III. Expediting study start-up, enrollment and ultimate study completion are utmost priorities for the company. We are leveraging our prior clinical experience and taking numerous measures to speed enrollment. I would like to highlight some of our recent progress. Our clinical team has finalized the ECOSPOR III study protocol, and the protocol has already been cleared by several institutional review boards. The study will enroll multiply recurrent C. diff patients who have experienced three or more C. diff episodes within the last 12 months. As previously mentioned, in all patients, the qualifying C. diff episode for study entry will be confirmed by cytotoxin assay. FDA-approved C. diff cytotoxin assays are broadly available. Nevertheless, we have decided to use a central lab for cytotoxin assays in the study to ensure both consistency and accuracy. We have completed substantial clinical site feasibility work and we have selected the large majority of planned ECOSPOR III investigator sites. ECOSPOR III subjects will include patients being treated as outpatients as well as inpatients located in hospitals, rehabilitation facilities and long-term care facilities. We plan to utilize over 100 clinical sites, a far larger number than utilized in our prior SER-109 study, and these sites will be geographically distributed so that much of the U.S. population will have access to this study, and we will also now include a number of Canadian clinical trial sites. I am very pleased with the rapid progress we've made preparing for the ECOSPOR III study and look forward to initiating the study in the middle of this year. I will now transition to discussing the important progress we have been making with our other microbiome therapeutic candidates. Let's begin with SER-262 program. We have continued to advance the SER-262 Phase Ib study to prevent recurrence in patients with primary C. diff infection. This is the first-ever clinical trial to evaluate a human synthetic, multi-strain microbiome therapeutic candidate. SER-262 is manufactured using bacteria grown in production fermenters in a process that does not require human donor material. SER-262 contains a consortium of 12 bacterial strains in spore form, rationally selected from Seres' field-leading proprietary bacterial library of over 14,000 well-characterized human microbiome strains. The strains included in SER-262 were selected based on multiple criteria, and the final SER-262 composition was optimized from over 100 different consortia that were evaluated in diverse preclinical studies. The SER-262 Phase Ib trial is a 24-week, randomized, placebo-controlled, dose-escalation study in patients who have experienced a first episode of C. diff infection. Our objectives are to demonstrate that SER-262, as the first synthetic microbiome therapeutic candidate, has an acceptable safety profile, results observed in the microbiome changes and reduces the risk of recurrent infection in primary C. diff patients. Our original SER-262 Phase Ib study design included 5 dose-escalating patient cohorts to evaluate single administrations of SER-262 doses ranging from 10 to the fourth spores to 10 to the eighth spores. Each patient cohort includes 10 treated patients as well as 2 placebo patients. Based on our learnings from our prior microbiome clinical development efforts, but especially and directly from our recent SER-109 Phase II root-cause analysis, we are considering modifying the SER-262 study protocol to include additional cohorts with SER-262 administered over multiple days and/or at higher doses. With these potential additional dosing regimens, we could evaluate the impact of multiple dosing on tolerability, microbiome changes and kinetics and recurrence rates with this potential first-in-class synthetic microbiome drug candidate. Through the SER-262 Phase Ib study, we expect to gather important information on the dosing effects of our microbiome therapeutics. Specifically, we anticipate that we will obtain data on how the therapeutic dose impacts subsequent microbiome changes. In addition, while this is a relatively small Phase I study, we hope to see a dose response and observe C. diff recurrence rates in patients treated with the higher doses of SER-262. Overall, we expect the SER-262 Phase Ib data to inform our future development efforts for SER-262 as well as our other microbiome R&D efforts. We continue to expect SER-262 Phase Ib top line study results in the second half of 2017. Now moving to the SER-287 program. We continue to execute our SER-287 Phase Ib multi-dose, placebo-controlled study in ulcerative colitis patients. Specifically, we are evaluating SER-287 as an induction therapy in patients with mild to moderate ulcerative colitis who are failing prior nonbiologic therapy. The rationale for evaluating microbiome therapy in ulcerative colitis is supported by several published controlled clinical studies which suggest that modification of the microbiome via repetitive fecal microbiota transplantation can result in a meaningful clinical response. The SER-287 Phase Ib study is evaluating three treatment arms that include daily or weekly SER-287 administration over the eight-week treatment period. The study will also evaluate vancomycin antibiotic pretreatment, the rationale being that reducing gastrointestinal bacterial levels prior to SER-287 administration may support engraftment of the microbiome therapeutic candidate. The study will enroll a total of approximately 55 subjects, with 15 in each treatment arm and 10 subjects in a placebo arm. As a Phase Ib study in a clinically heterogeneous disease, the SER-287 study's primary endpoints focus on safety, tolerability plus pharmacodynamics, as measured by microbiome changes. We hope to observe an acceptable safety profile and a normalization in study subjects' microbiomes following administration of SER-287. In addition, the study will also evaluate a number of exploratory efficacy measures, including various biomarkers and total Mayo Clinic scores. The Mayo Clinic score is a widely used ulcerative colitis clinical score comprising 4 components and resulting in a 0 to 12 scale, with 12 being the most severe. The components of the Mayo score include measures of stool frequency, rectal bleeding, endoscopic evaluation and physician global assessment. All endoscopies are centrally read in order to minimize site-to-site variability. Our objective with SER-287 is to develop an effective orally administered therapeutic option which is not immunosuppressive. There are approximately 700,000 ulcerative colitis patients in the U.S. alone. We believe that our microbiome therapies may have the potential to address a substantial proportion of UC patients who are not well managed by currently available drugs. In addition, there may be a substantial opportunity to better serve individuals suffering from UC not treated with currently available, later-line therapies because of safety risks including, but not limited to, immunosuppression, which can lead to opportunistic infections and opportunistic tumors associated with many of these drugs. Enrollment of the SER-287 study is nearing completion, and we look forward to SER-287 study results in the second half of this year. I'll now pass the call to Eric to review our recent financial performance.