Cardiovascular Effects of Drugs to Treat Diabetes

Transcription

1 Cardiovascular Effects of Drugs to Treat Diabetes Steven E. Nissen MD Chairman, Department of Cardiovascular Medicine Cleveland Clinic Disclosure Consulting: Many pharmaceutical companies Clinical Trials: Amgen, AstraZeneca, Eli Lilly, Takeda, Orexigen, Vivus, and Pfizer. Companies are directed to pay any honoraria, speaking or consulting fees directly to charity so that neither income nor tax deduction is received.

2 More than 50 years after the initial introduction of oral anti-diabetic drugs. Although cardiovascular disease is the cause of death in 50-75% of diabetics, there exist no well-designed, adequately-powered comparative effectiveness trials evaluating macrovascular outcomes for diabetes drugs

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4 Level of Evidence: Comparative Effectiveness Trials of Diabetes Drugs Outcome All cause mortality CV disease mortality Nonfatal MI or stroke Peripheral vascular disease Microvascular outcomes Level of Evidence Low to very low Low to very low Low to very low Low to very low Low to very low

5 University Group Diabetes Program (UGDP) Sulfonylureas introduced in 1955 as the first oral glucose lowering agents. At the urging of Congress, UGDP was organized in 1961 to study diabetes therapies: Placebo (diet only) Variable dose insulin Fixed dose insulin Tolbutamide Phenformin The tolbutamide arm stopped in 1970 for increased mortality, a warning ignored for the next 4 decades.

6 Kaplan-Meier Curves: UGDP All Cause Mortality Cardiovascular Mortality Reprinted from "Diabetes" 19: Copyright 1970 American Diabetes Association.

7 What was the Response to the UGDP Controversy? Answer Sponsors simply stopped conducting cardiovascular outcomes trials designed to determine the cardiovascular effects of drugs to treat diabetes Result The medical equivalent of the Dark Ages with no comparative efficacy trials for the next 40 years

8 Stagnation: Changes in CHD Mortality Rates in Patients with and without Diabetes 1970 s-80 s Diabetics Nondiabetics Men Women Men Women 10.7 Percent Change in Mortality In national sample of adults in NHANES I ( ) and NHANES II ( ). Gu K et al. JAMA 1999;281:

9 After UGDP, the Focus Shifts What are the benefits of glucose lowering on the incidence of CHD events? What glycemic target results in the best cardiovascular outcomes?

10 The Knowledge Gap The absence of information on macrovascular effects of diabetes therapies is the unfortunate consequence of current regulatory policy that emphasizes the importance of glucose lowering, not health outcomes, as a therapeutic goal.

11 This Approach Has Created a New Disorder Glucocentricity glu-co-cen-tricity ˈgloōkō senˈtrisitē noun The irrational belief that lowering blood sugar using virtually any pharmacological means will produce a reliable reduction in adverse outcomes

12 Muraglitazar: The first Dual PPAR A Wake up Call

13 Dual PPARs: A Promising Approach? Because both hyperlipidemia and hyperglycemia promote atherosclerosis in diabetics, companies sought dual α and γ PPAR agonists. Muraglitazar combined the effects of TZD s (rosiglitazone) and fibrates (fenofibrate) in a single molecular entity. Muraglitazar was the first dual PPAR to come before an FDA Advisory Committee with briefing materials posted Sept. 5, 2005 on FDA website.

14 HbA1c: Change from Baseline (%) Placebo Mura 2.5mg Mura 5mg Open 5mg Mean baseline Change in HbA1c (%) Placebo Muraglitazar 2.5mg Muraglitazar 5mg Open label 5mg

15 Lipid Parameters: Change from Baseline (%) Triglycerides HDL-cholesterol LDL-cholesterol Placebo Muraglitazar 2.5mg Muraglitazar 5mg

16 The panel votes 8:1 to approve muraglitazar as monotherapy and 7:2 to approve use with metformin. They vote 7:2 against approval in combination with sulfonylureas, requesting more data.

17 Six Weeks after the Advisory Panel

18 PPARs and CV Events: Muraglitazar All cause mortality plus nonfatal MI or stroke All cause mortality plus nonfatal MI, stroke, CHF or TIA Cardiovascular death, plus nonfatal MI or stroke Cardiovascular death plus nonfatal MI, stroke, CHF or TIA Relative Risk 2.23 ( ) 2.62 ( ) 2.21 ( ) 2.69 ( ) p value

19 Rosiglitazone

20 Rosiglitazone Registration (May 1999) Major concerns had emerged about hepatic toxicity of troglitazone (Rezulin). FDA was eager to approve a safer alternative. Both rosiglitazone and pioglitazone appeared free of life-threatening liver toxicity. The registration package for rosiglitazone consisted of 5 trials (2902 patients), mostly shortterm (24 weeks) glycemic-control studies. The drug was presented to an FDA Advisory Panel on May 22, 1999 and approved.

21 Rosiglitazone Data Extracted from FDA Reviewe for Advisory Panel (May 1999) Rosiglitazone Comparators Relative Risk 36/2902 (1.24%) 10/1452 (0.69%) 1.8 ( ) The FDA reviewer adjusted for time-on-drug and the signal became less dramatic (8.8 vs. 7.9 per 1000 pt yrs, RR=1.11)

22 Rosiglitazone Approval Package (1999) Percent Change from baseline in LDL-C* Baseline LDL Study 011 Study 024 Study 020 Overall 24% 20% 13% FDA-approved rosiglitazone product insert: 18.6% LDL-C increase for patients with mean baseline of 125 mg/dl *Statistical Review. Joy D. Mele M.S. Mathematical Statistician

23 2006: Updated GSK Integrated Analysis 42 randomized clinical trials enrolling 12,183 patients HR 95% CI Overall Pre-existing CHD/nitrates No CHD These data were also submitted to the FDA However, neither GSK, nor the FDA, made any public statement warning physicians or patients of the findings.

24 Odds ratio for myocardial infarction 1.43 (95% CI ) Odds ratio for cardiovascular death 1.64 (95% CI )

25 What About Pioglitazone?

26 2010 Pioglitazone Meta-analysis: MACE Pioglitazone vs. comparators: 746 events in 22,131 patients 16 Estimated Event Rate (%) HR = 0.80 ( ) P = Comparators Pioglitazone Number at Risk Time from Randomization (Days) Pio Comp

27 Lipids: Rosiglitazone vs. Pioglitazone 25% 20% 15% 10% 5% 0% -5% -10% -15% Triglycerides 14.9% P< % Non-HDL-cholesterol 18.6% P< % Rosiglitazone Pioglitazone -20% Goldberg et al. Diabetes Care 28: , 2005

28 Lessons from the TZD s: Two seemingly similar drugs can have very different effects on CV morbidity and mortality

29 The Third Strike: The Accord Trial

30 The ACCORD Trial: Mean A1C Levels at Each Study Visit A1C (%) Standard therapy Intensive therapy Years No. at Risk Standard therapy Intensive therapy Mean duration of follow-up = mean, 3.5; median, 3.4 yrs The ACCORD Study Group. N Engl J Med. 2008;358(24):

31 Primary and Secondary Outcomes Intensive N (%) Standard N (%) HR (95% CI) P Primary 352 (6.86) 371 (7.23) 0.90 ( ) 0.16 Secondary Mortality 257 (5.01) 203 (3.96) 1.22 ( ) 0.04 Nonfatal MI 186 (3.63) 235 (4.59) 0.76 ( ) Nonfatal Stroke 67 (1.31) 61 (1.19) 1.06 ( ) 0.74 CVD Death 135 (2.63) 94 (1.83) 1.35 ( ) 0.02 CHF 152 (2.96) 124 (2.42) 1.18 ( ) 0.17

32 Comparative Rates of Severe Hypoglycemia Proportion of Patients with at Least One Event Each Year 4.0% 3.2% Intensive control Standard control 2.4% 1.6% * 0.8% 0.0% * UKPDS ADVANCE ACCORD * Estimated

33 The Principal Dilemma How do we balance the need to bring new diabetes agents to patients in a timely fashion. vs. The need for more robust outcome data that inform physicians of how to use these drugs safely and effectively

34 Proposal: A Rational Approach to Approval of New Diabetes Drugs Requiring a large CV outcomes trial prior to approval is undesirable, because this approach would delay new diabetes therapies by 5-7 years. A Compromise with Two Components A pre-approval set of clinical trials designed to rule out a high level of CV risk (upper CI <1.8). To stay on the market, a large randomized outcomes trial after to rule our upper CI < 1.3

35 3.5 0 Examples: 2008 Cardiovascular Guidance Pre-approval Outcome Trial (122 events) 1.26 Initial Approval Not Approvable Approvable, No Further Study Post-approval Outcome Trial (620 events) 1.11 Stays on Market Withdrawal Potential Superiority Claim Hazard Ratio

36 Result of FDA Policy Change New Era of Research on Outcomes with Diabetes Drugs CV Outcomes Studies Initiated Planned Recruitment into Initiated Studies Mar '05 Feb '08 Mar '08 Feb ' Mar '05 Feb '08 Mar '08 Feb '11 Bethel MA and Sourij H. Curr Cardiol Rep 2012;14:59 69

37 Examine Trial: Alogliptin vs. Placebo White WB et al. N Engl J Med 2013 Sep 2 [Epub ahead of print]

38 Savor Trial: Saxagliptin vs. Placebo Sirica BM et al. N Engl J Med 2013 Sep 2 [Epub ahead of print]

39 Multifactorial Management in Diabetes The STENO 2 Study 13 Years of Follow-Up Composite endpoint: CV-death, MI or stroke, CABG or PCI, limb amputation or vascular surgery 80 Cumulative incidence of CV events (%) P<0.001 Conventional therapy Intensive therapy Follow up (years) Gaede et al New Engl J Med 2008; 358: 580

40 There is no virtue in practicing medicine in an evidence-free zone. We need clinical trial evidence of the benefits and risks for all drugs including diabetes agents. We need drugs that do more than merely lower blood glucose - we need therapies that reduce the enormous burden of cardiovascular disease in the diabetic population.

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