Download presentation
Presentation is loading. Please wait.
Published byTamsin Whitehead Modified over 9 years ago
2
The “Pharmaco” in Pharamcoepidemiology Alec Walker September 2013 1
3
Who Needs the “Pharmaco”? Epidemiology 221 is a course is for Epidemiologists in training New to drug safety research To explore recurring topics pharmacoepidemiology Through lectures and discussion, we will explore Examples of discovery of adverse drug effects Use of large databases Study designs for Large data resources Control for unmeasured confounding factors Institutional sensitivities Students will acquire Relevant vocabulary Key concepts Ability to pursue each of these topics in more depth 2
4
Epidemiology 221 Early Stories Discovery of Drug Effects Common Epidemiologic Designs Applied to Drugs Fall 2013 Alexander M. Walker MD, DrPH
5
Thomas Quasthoff German bass-baritone Born 1959 Recordings on Philips, EMI, BMG, Haenssler 1988 ARD International Music Competition in Munich 1996 Shostokovich Prize 1999 Tanglewood (Boston Symphony Orchestra) debut 1999 Exclusive Deutsche Grammophon contract Profiled in Time, People, Esquire, 60 Minutes
6
Quasthoff’s Mother Took Thalidomide Many European women used thalidomide, an apparently safe sleeping medication, during pregnancy in the late 1950s and 1960. Quasthoff, like thousands of others, was born with phocomelia.
7
The FDA as Public Health Guardians 6
8
Thalidomide in 1960 Painkiller, sedative Already in wide use around the world Generally felt to be harmless Over the counter in Germany since 1957 Richardson-Merrell submits application in US Hoping for approval by Christmas, when sedative sales generally peaked. 7
9
Frances Oldham Kelsey Francis Kelsey Public health hero? Foot-dragging bureaucrat? Spontaneous reports & pharmacovigilance 8
10
Delay in US Approval Heavy pressure for approval December reports of peripheral neuropathies in BMJ Kelsey keeps asking for more data 9 Florence AL. BMJ 1960(2):1954
11
Meanwhile … 1959 – 1969 Phocomelia epidemic recognized but not understood 1961 November 16 Wedekund Lenz identifies half of phocomelia patients as having been exposed to thalidomide at a conference December 2 (Lancet) UK Manufacturer notes rarity, lack of statistics, appeals for case reports, suspends sales December 16 (Lancet) McBride notes 20% major malformation risk in thalidomide pregnancies 10 1962 Richardson-Merrell withdraws application
12
Phocomelia
13
Fêted as a Heroes Distinguished Federal Civilian Service Award, August 7, 1962 Glowing write-up in Life 12
14
The Verdict of History 13 www.fda.gov/cder/pike/julyaug2001.htm
15
Induction into Women's Hall of Fame Frances O. Kelsey, Ph.D., M.D., was praised for her courage and influence at a special FDA reception to commemorate her induction last October into the National Women's Hall of Fame. Center Director Janet Woodcock, M.D., noted that Dr. Kelsey, a pharmacologist and physician, has long been honored for her role in blocking approval of the drug thalidomide. Dr. Kelsey's refusal to approve thalidomide for use in the United States earned her national recognition, and her work led to strengthened regulation of the pharmaceutical industry. Dr. Woodcock said that Dr. Kelsey has been an inspiration to many scientists in the Center who "stuck to their guns under great pressure.” 14 From “CDER News Along the Pike July & August 2001” www.fda.gov/cder/pike/julyaug2001.htm
16
The Recognition of Adverse Drug Reactions 15
17
It may be obvious: Toxicity is a simple matter of pharmacology
18
Some Paradigms for Discovery Pattern 1: Unique story Pattern 2: Distinct but delayed Pattern 3: Quantitative
19
Pattern 1: A Unique Story Clinically Detectable Effects Very short time interval Prior hypothesis Known mechanism No alternative explanation Simple exposure
20
Clinical Recognition A single observer With a class of applicable hypotheses Congruence between event and general rule Lack of competing explanation Pattern Recogn ition
24
Pattern Key
25
Angioedema and ACE Inhibitors Swelling of lips, mouth, throat Within hours to days of 1 st Rx 1 in 200 patients 1 in 100 life-threatening More common in blacks
26
Discovering Angioedema Case reports Short time Rare in the absence of exposure Distinctive characteristics No alternative etiology No reasonable doubt in after a case series
27
Pattern 2: Distinct but Delayed Striking, usually rare event Increased frequency leads to search Essentially 100% of cases exposed
28
Phocomelia Lancet, Dec 16, 1961
29
Phocomelia and Thalidomide Delayed No precedent (read: no pre-existing hypothesis) Distinctive pattern Became evident after single clinicians themselves had seen multiple cases
30
Pattern 3: Quantitative Known event Increased frequency Surveillance systems allow comparisons
31
Cerivastatin and Rhabdomyolysis 37 deaths reported in US 800,000 users Many months of accumulating reports Vs. 20 deaths in > 20 million users of other statins Rhabdomyolysis relatively common in all statin users For cerivastatin, principally in conjunction with gemfibrizil
32
Quantitative not Qualitative Common enough to be well known Infrequent enough that no one observer can quantify
33
Informal Inference: When it’s Easy … Very short time interval Prior hypothesis Known mechanism No alternative explanation Simple exposure Massive increase in frequency
34
Informal Inference: When it’s Difficult … Delayed Unanticipated No known mechanism Readily expected in absence of the drug Multiple treatment modalities Increased risk, but not overwhelmingly so
35
Crossing over from the Clinic to Population 34
36
How we evaluate causal connections 35 Theory Prediction Experiment Data
37
Theories for Drug Safety Case Reports Analogy Animal Experience Rumor
38
A Good Hypothesis Content = Refutability Refutability depends on predictions Make a hypothesis better By forcing it to make refutable predictions Experiments (studies) are data collection organized in such a way as to test refutable predictions
39
Toxic Epidermal Necrolysis SCARS
40
Severe Cutaneous Adverse Reaction Syndrome SCARS Toxic Epidermal Necrolysis
41
Stevens Johnson Syndrome, Rash Severe Cutaneous Adverse Reaction Syndrome SCARS Toxic Epidermal Necrolysis
42
Case-Finding Examination of Other Reports Stevens Johnson Syndrome, Rash Severe Cutaneous Adverse Reaction Syndrome SCARS Toxic Epidermal Necrolysis
43
Roles of Epidemiology Techniques for quantification Conceptual tools Mechanics Repository of experience (of error) Confounded associations Distortions of information
44
Epidemiology’s Tools Cohort studies Case control studies Correlational studies Surveillance
45
Cohort Studies A list of individuals at risk The passage of time The occurrence of events
46
Superinfection (1970s)
47
Case-Control Studies Cohort studies with sampling Captures covariates that would be difficult to ascertain Time-varying Resource intensive data collection
48
Case-Control Advantages Relatively inexpensive Relatively quick Useful for rare outcomes
49
Case-Control Shortcomings May not yield absolute risk Focuses on a single outcome Difficult to assure ascertainment Difficult to verify suitable controls
50
MI and CCBs
51
Correlational Studies Population frequency Population exposure Inference on association The problem of common cause
52
Suicide v. CCBs in Sweden
53
Epidemiology as a Language for Evaluating Risk Explicit definitions for concepts of risk Measures for comparison Vocabulary for describing multiple determinants Nosology of induced and artificial associations Experience of error
54
Wrapping Up Epidemiology needs to formalize, not sterilize our innate ideas of causality Epidemiology extends the vision beyond associations that are readily apparent Epidemiologists can play a role in every stage of drug development
55
Thank You!
Similar presentations
© 2024 SlidePlayer.com Inc.
All rights reserved.