Metabolic disorders are chronic diseases that affect millions of people. There is still a significant need for new therapies for these patients. According to the Centers for Disease Control and Prevention, diabetes affects more than 25 million people in the United States, or eight percent of the population, with type 2 diabetes constituting 90 to 95 percent of those cases.
Metabolic disease is a very large area of medical need and is another area in which we focus our drug discovery efforts. We now have three drugs in our pipeline to treat type 2 diabetes, each of which acts upon targets in the liver or fat tissue through a distinct mechanism to improve insulin sensitivity, reduce glucose production, or affect other metabolic aspects of this complex disease. We plan to keep building our metabolic disease franchise and we are expanding our focus beyond type 2 diabetes to obesity and nonalcoholic steatohepatitis, or NASH. NASH is a common and often asymptomatic liver disease that can cause irreversible damage to the liver, and lead to liver cirrhosis and cancer. There is a significant need to reduce liver fat in patients with metabolic disease because these patients can develop NASH if they accumulate too much fat in their liver.
Our approach is to develop antisense drugs that doctors can add to existing therapies to treat diabetes and obesity. One hurdle for traditional drug development is that most traditional drugs cannot selectively target a disease-causing protein without also affecting closely related proteins, which often results in unwanted side effects. We design our antisense drugs to target the gene responsible for producing the disease-causing protein while avoiding unwanted effects on closely related proteins, thereby reducing the risk of side effects. In addition, the liver and fat cells produce many of the most important therapeutic targets for metabolic disease, and our antisense drugs distribute to the liver and fat cells and inhibit the production of key therapeutic targets in these organs.
ISIS-PTP1BRx is an antisense drug that targets protein tyrosine phosphatase-1B, or PTP-1B, to treat type 2 diabetes. PTP-1B is a phosphatase that negatively regulates insulin receptor signaling and is responsible for turning off the activated insulin receptor. Reducing PTP-1B enhances insulin activity. Scientists have long recognized PTP-1B as an attractive target to treat diabetes, but due to structural similarities among closely related proteins, pharmaceutical companies have had difficulty identifying small molecule drugs with sufficient specificity to be safe. We designed ISIS-PTP1BRx to increase the body’s sensitivity to the natural hormone insulin, resulting in better glucose control for patients with type 2 diabetes. Because of its unique mechanism, ISIS-PTP1BRx may help treat type 2 diabetes without causing weight gain or hypoglycemia, also known as low blood sugar. The reductions in LDL-C produced by inhibiting PTP-1B should also provide an added benefit to patients.
Phase 2 studies of ISIS 113715, our previous PTP-1B inhibitor, showed that inhibiting PTP-1B could help patients with type 2 diabetes. In those studies, inhibiting PTP-1B improved glucose control and reduced LDL-C in both newly diagnosed diabetic patients and in patients who were taking sulfonylureas. The patients in these studies also did not gain weight, indicating another substantial advantage in treating diabetic patients who are frequently obese and at high cardiovascular risk.
We have completed a Phase 1 study evaluating the safety of ISIS-PTP1BRx in healthy volunteers. In this study, subjects tolerated ISIS-PTP1BRx well. We also observed encouraging data in measures of insulin sensitivity and in a biomarker associated with weight loss. These Phase 1 data are consistent with our findings from our Phase 2 ISIS 113715 studies and support our preclinical observations of increased potency with ISIS-PTP1BRx compared to ISIS 113715.
We believe that physicians may use ISIS-PTP1BRx in combination with most of the other commonly used drugs, including insulin, GLP-1 agonists, and more traditional drugs like metformin, to treat patients with diabetes. The clinical development plan for ISIS-PTP1BRx focuses on treating diabetic patients who are inadequately controlled on insulin, helping them utilize insulin more efficiently and treating patients who are beginning to fail oral therapies, extending the time they have before becoming dependent on insulin. In 2013, we plan to initiate a Phase 2 study in patients with type 2 diabetes who despite taking metformin have uncontrolled glucose levels.
ISIS-GCCRRx is an antisense drug that targets GCCR. Glucocorticoid hormones effect a variety of processes throughout the body, including promoting liver glucose production and fat storage. Scientists associate excessive GCCR activity in the liver and fat with obesity, insulin resistance and glucose intolerance. Although scientists have long recognized inhibiting GCCR as an attractive strategy for improving glycemic and lipid control in patients with type 2 diabetes, the side effects associated with systemic GCCR inhibition have challenged traditional drug developers. Antisense inhibitors of GCCR take advantage of the unique tissue distribution of oligonucleotides that allows the antisense drugs to inhibit glucocortocoid action primarily in liver and fat tissue. Notably, antisense drugs delivered systemically do not reduce GCCR expression in the central nervous system or adrenal glands, which could lead to systemic side effects. Reducing GCCR specifically in the liver and fat tissues is an attractive therapeutic approach because it lowers glucose and lipids, without causing potential side effects associated with systemic GCCR inhibition.
In preclinical studies, we showed that we can reduce GCCR specifically in the liver and fat tissues. In addition, we have shown that antisense inhibition of GCCR produced robust lowering of blood glucose, lipid levels and decreased body fat in obese animals. We have completed a Phase 1 study evaluating the safety of ISIS-GCCRRx in healthy volunteers. In this study, subjects tolerated ISIS-GCCRRx well, and we observed reductions of GCCR specifically in the liver and fat tissues, consistent with our preclinical observations.
We believe that doctors could use ISIS-GCCRRx in diabetic patients with moderate to severe hyperglycemia who are also obese or have high levels of cholesterol and triglycerides. We also believe that there are other attractive therapeutic opportunities for doctors to use ISIS-GCCRRx in patients with diseases in which there is glucocorticoid excess, such as Cushing’s Syndrome, and other diseases where a selective GCCR inhibitor could be beneficial. We plan to develop ISIS-GCCRRx to treat patients with Cushing’s Syndrome.
ISIS-GCGRRx is an antisense drug that targets the glucagon receptor, or GCGR, to reduce the effects of glucagon. Glucagon is a hormone that opposes the action of insulin and stimulates the liver to produce glucose, particularly in type 2 diabetes. In patients with advanced diabetes, uncontrolled glucagon action leads to a significant increase in blood glucose levels. Therefore, attenuating glucagon action could have a significant glucose lowering effect in patients with severe diabetes. In addition, reducing GCGR produces more active glucagon-like peptide, or GLP-1, a hormone that preserves pancreatic function and enhances insulin secretion. Therefore, we believe we can help control type 2 diabetes by using an antisense drug to reduce GCGR, which will stop the liver from producing too much glucose while preserving pancreatic function.
We conducted preclinical studies in the most insulin-resistant models of type 2 diabetes. In these studies, antisense reduction of GCGR decreased excessive liver glucagon action, produced robust glucose control, reduced levels of triglycerides and helped preserve the pancreas without producing hypoglycemia. Although researchers have developed and evaluated small molecule inhibitors of GCGR and observed glucose-lowering effects, treatment with these small molecule inhibitors also produced side effects limiting their potential use as drugs, including increases in lipids and blood pressure. We have completed a Phase 1 study evaluating the safety of ISIS-GCGRRx in healthy volunteers. In this study, subjects tolerated ISIS-GCGRRx well with no clinically significant increases in lipids or blood pressure and with no hypoglycemia. In addition, we observed an increase in active GLP-1, which was consistent with our preclinical observations.
Given the unique mechanism of action and potentially favorable safety profile observed in the Phase 1 study, we believe that doctors could use ISIS-GCGRRx in diabetic patients with severe hyperglycemia who are not controlled with current treatments and who could benefit from a drug that significantly decreases glucose levels and preserves pancreatic function.
ISIS-FGFR4Rx is an antisense drug that specifically reduces the production of fibroblast growth factor receptor 4, or FGFR4, in the liver and fat tissues, which decreases the body’s ability to store fat while simultaneously increasing fat burning and energy expenditure. Many anti-obesity drugs act in the brain to suppress appetite, commonly resulting in CNS side effects. However, ISIS-FGFR4Rx does not distribute to the brain or CNS and therefore should not produce any CNS side effects.
In preclinical studies, antisense inhibition of FGFR4 lowered body weight when we administered it as a single agent and in the presence or absence of a calorie-restricted diet. Additionally, inhibiting FGFR4 decreased body weight when we administered it in combination with an appetite-suppressing drug. In addition to reducing body weight, inhibiting FGFR4 demonstrated an improvement in insulin sensitivity. ISIS-FGFR4Rx is the first drug in our metabolic franchise to treat obesity and utilizes technology we in-licensed from Verva Pharmaceuticals Ltd.
ISIS-DGAT2Rx is an antisense drug that specifically reduces the production of diacylglycerol acyltransferase-2, or DGAT-2, a key component in the synthesis of triglycerides. By reducing DGAT2, ISIS-DGAT2Rx should reduce liver fat in patients with NASH. The NIH estimates that NASH affects more than 20 million people in the United States and expects the number to increase as the rate of obesity rises. There are no effective therapies available for patients with NASH and current treatments consist only of lifestyle changes. In addition, because clinicians associate increases in liver fat with insulin resistance, ISIS-DGAT2Rx could also benefit patients with type 2 diabetes who are insulin resistant.