Cardiovascular

Cardiovascular disease is the leading cause of death in the United States. A common cause of cardiovascular disease is atherosclerosis, or hardening of the arteries, that occurs when cholesterol and inflammatory cells accumulate in blood vessels. Researchers have shown a strong correlation between high cholesterol levels and subsequent cardiovascular diseases. Lowering cholesterol is a key component in preventing and managing cardiovascular disease. Another independent risk factor for cardiovascular disease is high levels of C-reactive protein, or CRP, which clinicians associate with significantly worse outcomes in patients with cardiovascular disease.

We continue to build our cardiovascular disease franchise by evaluating potential drug targets that influence the onset and progression of cardiovascular disease, and we intend to expand our franchise with additional drugs to treat various aspects of cardiovascular disease through complementary mechanisms. We recently added ISIS-APOCIII_Rx to our pipeline for the treatment of hypertriglyceridemia. We designed ISIS-APOCIII_Rx to manage triglycerides levels and provide an alternate, yet complementary, approach to lipid management.

• Mipomersen (High Risk/High Cholesterol)
• ISIS-CRP_Rx (Coronary Artery Disease)
• BMS-PCSK9_Rx (Cardiovascular Disease)
• ISIS-FXI_Rx (Clotting Disorders)
• ISIS-APOCIII_Rx (High Triglycerides)

Mipomersen

Mipomersen is a first-in-class apolipoprotein B, or apoB, synthesis inhibitor, or ABSI, currently in Phase 3 development as a potential novel treatment to reduce LDL-C in patients with high cholesterol and who are at high cardiovascular risk. Mipomersen is a second-generation antisense drug administered to patients through a once-weekly subcutaneous injection. It acts by decreasing the production of apoB, which provides the structural core for all atherogenic lipids, including LDL-C, which carry cholesterol through the bloodstream. In June 2008, we licensed mipomersen to Genzyme as part of a strategic transaction to develop and commercialize mipomersen.

In February 2010, we and Genzyme reported positive top-line data from our second Phase 3 trial evaluating mipomersen in patients with heterozygous FH. This is the second study to report from our broad Phase 3 program, and we expect the study to support the first regulatory filings in the U.S. and E.U. These two filings may also include patients with severe hypercholesterolemia.

Mipomersen Development

Mipomersen is intended to reduce LDL-C by preventing the formation of lipids that are responsible for the buildup of plaque in the arteries. The current recommendations for LDL-C goals from the National Cholesterol Education Program’s Adult Treatment Panel III are less than 100 mg/dL for patients with very high cardiovascular risk and less than 130 mg/dL for patients with moderate cardiovascular risk. We and Genzyme are developing mipomersen for patients whose LDL-C levels exceed these recommendations despite taking maximally tolerated lipid-lowering treatments.

In Phase 2 studies, we evaluated mipomersen in multiple patient populations and as a single-agent and in combination with other lipid-lowering therapies. We reported data showing that mipomersen lowered LDL-C in all patient populations tested. Mipomersen lowered LDL-C when used either as a single agent or in combination with other lipid-lowering medicines. In addition, mipomersen lowered serum apoB, non-high-density lipoprotein-cholesterol, or non-HDL-C, triglycerides and lipoprotein (a), or Lp(a), all generally accepted risk factors for cardiovascular disease.

In November 2009, we and Genzyme reported positive data from a Phase 3 trial evaluating mipomersen in patients with homozygous FH. We designed the Phase 3 study in homozygous FH patients to test the efficacy and safety of adding mipomersen to substantial lipid-lowering therapy. The Phase 3 trial was a randomized, double-blind, placebo-controlled study that enrolled 51 homozygous FH patients and is one of the largest trials to date in this rare patient population. Patients were randomized 2:1 to receive a 200 mg dose of mipomersen or placebo by weekly injections for 26 weeks. The trial was conducted at 10 sites in seven countries in North America, Europe, Asia, South America and Africa.

We and Genzyme reported that the trial met its primary endpoint in an intent-to-treat analysis with a 25 percent reduction in LDL-C after 26 weeks of treatment, vs. 3 percent for placebo (p<0.001), which constitutes an average reduction of LDL-C greater than 100mg/dL. The study also met all of its secondary and tertiary endpoints, suggesting that mipomersen may offer potential benefits beyond LDL-C reduction. Patients treated with mipomersen experienced a 27 percent reduction in apoB vs. 3 percent for placebo; a 21 percent reduction in total cholesterol vs. 2 percent for placebo; and a 25 percent reduction in non-HDL cholesterol vs. 3 percent for placebo (all p<0.001). Reductions were observed in other atherogenic lipids, including Lp(a) by 31 percent and VLDL-C by 17 percent (both p<0.01 vs. placebo); and triglycerides by 18 percent (p=0.013 vs. placebo). Mipomersen patients’ HDL-C levels increased 15 percent (p=0.035 vs. placebo), which combined with the LDL-C reductions observed, resulted in improved LDL/HDL ratios, a ratio considered an important measure of cardiovascular risk. Mipomersen patients’ LDL/HDL ratios decreased by 34 percent (p<0.001 vs. placebo). Although the patients were on maximally tolerated statins and other lipid-lowering therapies, their average LDL-C at baseline was greater than 400 mg/dL, confirming that the population is one in which LDL-C reduction is challenging to achieve. The reductions observed in the study were in addition to those achieved with the patients’ existing therapeutic regimen.

Of the 34 patients treated with mipomersen, 28 completed the study. Of the six discontinuations, one patient discontinued due to elevations in liver transaminases that did not represent a Hy’s Law case, an indicator of drug-induced liver injury, and was not associated with any other signs of liver toxicity. Of the remaining discontinuations, two patients stopped treatment due to injection site reactions, one patient stopped treatment due to a rash, one patient stopped treatment for personal reasons and one patient was discontinued due to patient non-compliance. Consistent with previous studies evaluating mipomersen, the most commonly observed adverse events were injection site reactions, flu-like symptoms and elevations in liver transaminases. Four patients had elevations in liver transaminases above 3 x ULN, or three times the upper limit of normal, three of whom reached between 5 and 8 x ULN. None of these patients, including the patient who discontinued the study, had changes in other laboratory tests to indicate liver dysfunction. In all cases, transaminases returned to entry criteria by the end of planned clinical observations.

In February 2010, we and Genzyme reported positive top-line data from a second Phase 3 study that evaluated mipomersen in patients with heterozygous FH. This study met its primary endpoint, with a highly statistically significant 28 percent reduction in LDL-C, after 26 weeks of treatment, compared with an increase of 5 percent for placebo (p<0.001). This study also met each of its secondary endpoints of reduction in apoB, total cholesterol and non-HDL cholesterol. Consistent with our previous studies evaluating mipomersen, the most commonly observed adverse events were injection site reactions and flu-like symptoms.

The study was a randomized, double-blind, placebo-controlled trial that enrolled 124 heFH patients, aged 18 and older with LDL-C levels greater than 100 mg/dL. Patients were randomized 2:1 to receive a 200 mg dose of mipomersen or placebo weekly for 26 weeks. All of the 124 patients in the study had pre-existing coronary artery disease, were taking a maximally tolerated dose of a statin and in many cases additional lipid-lowering drugs. Patients’ average LDL-C at baseline was 150 mg/dL. Patients treated with mipomersen had an average LDL-C level of 104 mg/dL at the end of the study. Forty-five percent of the mipomersen-treated patients achieved LDL-C levels of less than 100 mg/dL, a recognized treatment goal for high-risk patients. The reductions observed in the study were in addition to those achieved with the patients’ existing therapeutic regimens.

There were no new areas of safety concerns identified in the trial. Of the 83 patients treated with mipomersen, 73 completed the study; nine of the discontinuations were related to adverse events. Consistent with previous studies evaluating mipomersen, the most commonly observed adverse events were injection site reactions and flu-like symptoms. As in other mipomersen trials, elevations in liver transaminases were observed that were similar in magnitude and duration to those seen in other studies. None of these patients had changes in other laboratory tests to indicate hepatic dysfunction, and there were no Hy’s Law cases. Full data from this study will be presented at a future medical meeting.

We and Genzyme are currently conducting a broad clinical program evaluating mipomersen in different patient populations. We have completed enrollment in the following mipomersen studies including:

• A Phase 3 study in 58 patients with severe high cholesterol;
• A Phase 3 study in 158 high cholesterol patients at high risk for coronary heart disease; and
• A Phase 2 study in high-risk, high-cholesterol patients who are intolerant to statins.

We and Genzyme expect to report the data from the remaining two Phase 3 studies in mid-2010. The data from all of the Phase 3 mipomersen clinical studies will help inform the design of a clinical outcomes study of mipomersen. The outcomes study may also support the eventual potential expansion of mipomersen’s label to include a broader group of high-risk, high-cholesterol patients.

Mipomersen Commercialization

The U.S. Food and Drug Administration, or FDA, has granted mipomersen Orphan Drug designation for treating patients with homozygous FH. Orphan Drug designation encourages and facilitates development of drugs for rare diseases, offering potential tax credits and marketing incentives upon approval.

Genzyme’s initial U.S. and E.U. regulatory filings for mipomersen will seek marketing approval for the treatment of patients with homozygous FH. These two filings may also include patients with severe hypercholesterolemia. A Phase 3 study of mipomersen in patients with severe hypercholesterolemia is fully enrolled and we anticipate data in mid-2010. With the completion of enrollment in this study, the last of the four Phase 3 studies that will form the basis for the first regulatory filings, Genzyme continues to refine and expand the regulatory and commercial strategy for mipomersen. By mid-2011, Genzyme expects to have filed for approval in the U.S. and E.U. and to have made progress toward filing in other major international markets. In addition, we and Genzyme expect that data from all of the mipomersen trials described above will be available at the time of the initial submissions, and this data will continue to build the body of clinical evidence around mipomersen’s value in managing high-risk, high-cholesterol patients. Following a successful severe hypercholesterolemia submission in Europe, Genzyme plans to file a second submission in Europe for heterozygous FH patients. Genzyme and Isis are also planning an outcomes study that may support the potential expansion of mipomersen’s indication to include a broader group of high-risk, high-cholesterol patients.

About FH

FH is a genetic disorder in which patients cannot properly metabolize LDL-C, resulting in elevated LDL-C levels. FH patients experience a markedly increased risk of premature cardiovascular disease. There are two forms of FH: homozygous FH, where the patient inherits the same defective gene from both parents, and heterozygous FH where the patient inherits the defective gene from only one parent, thereby preserving some normal gene function. The homozygous form of FH is a very rare condition estimated to affect approximately one in a million people. Homozygous FH patients can have LDL-C levels greater than 600 mg/dL and are at very high risk for early coronary events and sudden death. Because many patients are resistant to the lipid-lowering effects of currently available therapies, it is difficult to effectively treat homozygous FH patients. Heterozygous FH is a more common form of the disorder, with a prevalence of approximately one in 500, and results in untreated LDL-C levels of approximately 300 mg/dL, double those of the general population.

ISIS-CRP_Rx

ISIS-CRP_Rx is an antisense drug that targets CRP, a protein produced in the liver. CRP levels increase dramatically during inflammatory disorders, and excessive amounts of CRP have been linked to coronary artery disease. Furthermore, a growing body of evidence from clinical trials implicates CRP in cardiovascular disease progression.

These results suggest that it may be therapeutically beneficial to significantly decrease CRP levels in patients who are at risk for coronary events. In addition, clinicians have associated elevated CRP levels with a worsening of overall outcomes in conditions such as end-stage renal disease and multiple myeloma, suggesting that lowering CRP could help these patients. CRP elevation is also evident in many other major inflammatory diseases such as Crohn’s disease and rheumatoid arthritis.

In preclinical studies, we observed dramatic suppression of liver and serum CRP levels with our antisense inhibitor of CRP. ISIS-CRP_Rx is currently in a Phase 1 blinded, randomized, placebo-controlled, dose-escalation study designed to assess the safety and pharmacokinetic profile of our drug in addition to the initial effects of our drug on baseline CRP levels in healthy volunteers. Once completed, we intend to initiate a broad Phase 2 program on ISIS-CRP_Rx and evaluate ISIS-CRP_Rx in patients with multiple myeloma, rheumatoid arthritis with stable high CRP levels, atrial fibrillation following cardiopulmonary bypass and end-stage renal disease.

BMS-PCSK9_Rx

BMS-PCSK9_Rx is an antisense drug that specifically targets proprotein convertase subtilisin/kexin type 9, or PCSK9, an important protein involved in the metabolism of cholesterol and LDL. Its role is to break down the cell surface receptor that captures LDL particles. Therefore, inhibiting PCSK9 increases the number of receptors available to remove LDL-C from the bloodstream. Genetic studies in humans have demonstrated that elevated PCSK9 can lead to severely high levels of LDL-C, whereas low PCSK9 is associated with low LDL-C levels. These observations suggest that it may be therapeutically beneficial to decrease PCSK9 levels in patients who are at risk for atherosclerosis and cardiovascular disease. We believe that BMS-PCSK9_Rx could offer a new and complementary mechanism to current lipid-lowering therapies to prevent and treat cardiovascular diseases.

In May 2007, Bristol-Myers Squibb entered into a collaboration with us to identify antisense drugs that target PCSK9. In 2008, we achieved the first milestone in this collaboration with the selection of BMS-PCSK9_Rx as a development candidate. BMS is currently evaluating BMS-PCSK9_Rx in a Phase 1 study.

ISIS-FXI_Rx

ISIS-FXI_Rx is an antisense drug designed to treat clotting disorders. It targets Factor XI, a clotting factor produced in the liver. High levels of Factor XI are linked to heart attack, stroke and blood clots. In preclinical studies, ISIS-FXI_Rx demonstrated potent antithrombotic activity and a superior safety profile (lower risk of bleeding) compared with standard anti-clotting agents, including low molecular weight heparin, warfarin and Factor Xa inhibitors. We plan to begin IND-enabling studies on ISIS-FXI_Rx in the first half of 2010.

ISIS-APOCIII_Rx

ISIS-APOCIII_Rx is an antisense drug designed to lower triglycerides to treat hypertriglyceridemia. Hypertriglyceridemia is an independent risk factor for cardiovascular disease and is also a hallmark of metabolic syndrome, which occurs in a large percentage of people with type 2 diabetes. ISIS-APOCIII_Rx targets apolipoprotein C-III, or apoC-III, a protein synthesized in the liver that plays a central role in the regulation of serum triglycerides. Recent data suggest that loss-of-function mutations within the apoC-III gene lower triglycerides levels and appear to improve health and extend longevity. Clinical studies have demonstrated an association between apoC-III, metabolic syndrome and coronary heart disease. In addition, insulin resistance has been shown to be mediated through apoC-III, leading to worsening of the metabolic syndrome.

In preclinical studies, ISIS-APOCIII_Rx mitigated symptoms of metabolic syndrome and reduced atherosclerosis in mice. We added ISIS-APOCIII_Rx to our development pipeline in late 2009.