Efficacy and Safety of SYN-010 in IBS-C

Inclusion Criteria: * Male or female participants aged between 18 and 65 years inclusive. * Patient must be willing and able to participate in the study for the required duration, understand and sign the informed consent (ICF), and be willing to comply with all protocol-related visits and procedures. * Patient has had IBS-C symptoms (as defined by Rome III diagnostic criteria) for at least 6 months prior to diagnosis. * Patient has an average score of ≥ 3.0 for daily abdominal pain at its worst (11-point numerical rating scale \[NRS\]) during and up to the 17 days immediately before randomization (i.e. Pre-treatment Period). * Patient has an average of ≤ 3 CSBMs per week or ≤ 5 SBMs per week during the 17 days immediately before randomization (i.e. Pre-treatment Period). * Patient has a breath methane level ≥ 10 ppm on a lactulose breath test administered at Screening. * Patient may be on a stable, continuous regimen of fiber or probiotics one month before the Screening Visit; however, they must maintain a stable dose regimen through Week 12. * Patient must agree to refrain from starting a new diet, changing stable dose of supplemental fiber, or changing exercise pattern that may affect IBS-C symptoms from the time of Screening through the end of the study. If the patient takes food products that are strong inhibitors of cytochrome P450 3A (CYP3A) (e.g. grapefruit juice, Seville orange juice, St. John's Wort), he/she must agree to refrain from taking these from the time of Screening through the end of the study. * Patient must agree to use an acceptable method of contraception from the time of signing the ICF to 30 days after the final dose of study drug if the patient is a sexually active female of child-bearing potential (defined as any female who has experienced menarche and who is NOT permanently sterile or postmenopausal. Postmenopausal is defined as 12 consecutive months with no menses without an alternative medical cause). Adequate contraceptive measures include: oral contraceptives (stable use for two or more cycles before Screening); intrauterine device; Depo-Provera®; Norplant® System implants; partner with a vasectomy; double-barrier birth control (e.g. use of a condom plus diaphragm or condom plus either contraceptive sponge, foam, or jelly); or abstinence. According to drug research standards, male patient must agree to use an acceptable method of contraception and refrain from donating sperm from the time of signing the ICF to 90 days after the final dose of study drug. * A female patient of child-bearing potential must be non-pregnant and non-lactating and have negative pregnancy tests at the Screening Visit and on Day 1 prior to dosing with study drug. * Patients must be able to understand and be willing to sign the written informed consent form. A signed informed consent form must be appropriately obtained prior to the conduct of any trial-specific procedure. * Willing and able to comply with the protocol, including follow-up visits and examinations. Exclusion Criteria: * Patient has loose (mushy) or watery stools for \> 25% of their bowel movements (BMs) during the 12 weeks before Screening or during the Screening and Pre-treatment Periods. * Patient has a history of cathartic colon, laxative, or enema abuse. * Patient has a history of ischemic colitis. * Patient has a history of pelvic floor dysfunction. * Patient has a history of bariatric surgery for the treatment of obesity. * Patient has a history of surgery to remove a segment of the gastrointestinal (GI) tract at any time before the Screening Visit. * Patient has any history of myopathy, rhabdomyolysis, chronic myalgia, or familial history of hereditary muscular disorders. * Patient has been diagnosed with or has a family history of familial adenomatous polyposis, hereditary nonpolyposis colorectal cancer, or any other form of familial colorectal cancer. * Patient currently has any structural abnormality of the GI tract or a disease or condition that can affect GI motility, or any unexplained and clinically significant symptoms such as lower GI bleeding, rectal bleeding, heme-positive stool, iron-deficiency anemia, weight loss, or systemic signs of infection. * Patient has had any previous surgery involving the abdomen, pelvis, or retroperitoneal region during the last 12 months prior to Screening, with the exclusion of laparoscopic gallbladder surgery or appendix removal. * Patient has a history of diverticulitis or any chronic condition that could be associated with abdominal pain or discomfort and could confound the assessments in the study (e.g. inflammatory bowel disease, chronic pancreatitis, polycystic kidney disease, ovarian cysts, endometriosis, or lactose intolerance). * Patient has history of severe renal insufficiency defined as an actual or estimated glomerular filtration rate of \< 30 mL/min/1.73 m2 within the 6 months prior to Screening Visit. * Patient has any history of a medical condition or a concomitant medical condition that, in the opinion of the investigator, would compromise the patient's ability to complete the study safely or could confound the assessments in this study (e.g. uncontrolled hypothyroidism). * Patient is known to have elevated liver enzyme levels (aspartate aminotransferase \[AST\], alanine aminotransferase \[ALT\], alkaline phosphatase \[ALP\]) or creatine kinase levels that are ≥ 1.5 times the upper limit of normal (ULN) that have not been resolved within the 4 weeks prior to consent and/or these elevated levels are present at the Screening Visit laboratory assessment. * Patient has any abnormal laboratory results, electrocardiogram (ECG) findings, or physical examination findings deemed clinically significant by the investigator during the Screening Period. * Within 14 days prior to the Screening Visit, patient has used concomitant medications that are: (1) moderate-to-strong inhibitors of cytochrome P450 3A (CYP3A) and/or organ anion transporting polypeptide (OATP)1B1 (e.g. cyclosporine, verapamil, dronedarone, diltiazem, amiodarone, itraconazole, ketoconazole, posaconazole, voriconazole, clarithromycin, telithromycin, human immunodeficiency virus protease inhibitors, boceprevir, telaprevir, nefazodone, erythromycin, cobicistat-containing products); (2) other concomitant medications that are excluded from the lovastatin label (e.g. rifampin, colchicine, ranolazine); or (3) metformin or GLP-1 agonists. Patients should not take any of these concomitant medications during the treatment phase of the study without contacting the investigator. * Patient has hypersensitivity to statins; or has used any statins, fibrates, \> 1 g/day of niacin, or gemfibrozil within the 3 months prior to the Screening Visit. * Patient reports current chronic or frequent use of drugs known to cause constipation (e.g. narcotics) for the 3 months prior to Screening. * Patient has taken over-the-counter IBS treatments (e.g. laxatives) or proton pump inhibitors within 3 days prior to the Screening Visit. * Certain drugs used for the treatment of IBS (e.g. low dose tricyclic antidepressants) may be allowed at the discretion of the Medical Monitor provided the patient remains on a stable dose for one month prior to the Screening Visit and throughout the study with the exception of tegaserod, lubiprostone, linaclotide, metoclopramide, prucalopride, domperidone, or antibiotics within 2 months prior to the Screening Visit. Certain drugs used for the treatment of IBS (e.g. low dose tricyclic antidepressants) may be allowed at the discretion of the Medical Monitor provided the patient remains on a stable dose for one month prior to the Screening Visit and throughout the study with the exception of tegaserod, lubiprostone, linaclotide, metoclopramide, prucalopride, domperidone, CandiBactin, Atrantil, Allimax/Allimed within 2 weeks prior to the Screening Visit or antibiotics within 2 months prior to the Screening Visit. * Patient has used an opioid chronically or frequently within the 3 months prior to the Screening Visit and for the duration of the study. * Patient is currently enrolled in, or plans to enroll in, another clinical study or has used any investigational drug or device within 1 month before signing the ICF through the completion of the study. * Patient has previously participated in a SYN-010 study. * Patient has a history of alcohol or drug abuse within the 12 months prior to the Screening Visit.