Pharm 100 - Lesson A.2
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1. Catch audience attention:
In order to catch audience (the physician’s) attention, a stimulus competing with the drug is utilizedwhich is effective in drawing the eye to the advertisement. An example of this technique is a colourfulpicture of a snowmobile race to attract the eye with the caption “Lincocin offers you a ‘leading edge’over penicillin in streptococcal infections”. In fact, Lincocin was later shown to possess severe adverseeffects and is no longer utilized in therapeutics.
2. Use of celebrities or authorities to endorse products:
An example of this technique is an advertisement depicting three middle-aged physicians engaged inpatient care entitled “Keflin I.V. – 10 years of clinical experience”. Keflin is a member of thecephalosporin family of antibiotics (related to the penicillin family). The clear implication is that, ifthese authority figures have selected the drug, it must be the drug of choice.
- An example of this technique shows a woman at six stages of her life, beginning as an attractive,upright women, and with advancing years developing into a semi-crippled, hunched-over old woman. The advertisement reads as follows:
- “Every fourth menopausal womanmay develop osteoporosisOS@Cal can help”
- OS@Cal is a mixture of calcium and Vitamin D
4. Offering an easy solution to problems:
- An advertisement of this type for Atarax, an antihistamine, has the following statement:
- “Problem child or child with a problem?”
- It then shows four pictures of children labelled respectively: troublemaker, bed-wetter, picky eater,and nervous stomach. The implication is that these childhood conditions are treatable by Atarax. Thistype of advertisement in medical journals aroused considerable controversy and has been banned
5. Before-after technique:
- An advertisement of this type for Clinoril is entitled:
- “When osteoarthritis begins to interfere”
- The advertisement shows an unhappy, elderly, grey-haired woman. Subsequently, we see the samewoman smiling and happy with the caption:
- “Clinoril can do”
6. Discredit drugs produced by other manufacturers and praise your own:
- An example of this type of advertisement depicts a man and a woman on exercise bicycles and it isentitled:
- “This is no time to have to worry about your antihypertensiveBut the potential risks of diureticscould make it just the time for Lopressor SR”
- Hypertension (high blood pressure) is a widespread problem and there are many drugs marketed forthe treatment of this condition. Two of the most common drugs used to initiate therapy are diuretics andbeta-blockers. Lopressor SR is a beta-blocker. Thus, the advertisement implies that the beta-blocker,Lopressor SR, is a better choice than a diuretic.
If a pharmaceutical manufacturer wishes to introduce a new drug into therapeutics and to conduct a trial in humans of the new drug, the following steps are required.
- 1. The manufacturer is required to submit proof of both the safety and the efficacy of the drug in severalanimal species to the government regulatory agency in the particular country concerned, namely theHealth Protection Branch in Canada, and the Food and Drug Administration in the U.S.A.
- 2. The detail methodology for the proposed clinical trial in humans is required.
- 3. The pharmaceutical manufacturer’s detailed submission is carefully evaluated by qualified scientistsin the regulatory agency. If the regulatory agency is satisfied, permission will be given for highlyqualified investigators, usually clinical pharmacologists, to initiate careful investigation of the drug inhumans. Particular care is required since animal studies, no matter how carefully conducted, will notalways predict drug behaviour in humans.
4 stages of a clinical trial:
- Phase 1: Study conducted in a limited number of healthy volunteers. The absorption, distribution,elimination and adverse effects of the new drug are carefully studied.
- Phase 2: The objective of this phase is to determine whether the drug is effective in treating the condition for which it is recommended in a limited number of people. Careful attention ispaid to the safety of the drug
- Phase 3: The drug is now tested in a larger number of people (usually approximately onethousand). The safety of the drug is carefully studied.
- Phase 4: Risks that are delayed or less frequent than 1 in 1,000 administrations may be missed inthe Phase 3 trial. Thus, surveillance of the effects of drugs are required after the drug isreleased for general use. This phase is therefore referred to as postmarketing surveillance.
A placebo is defined as an inert substance which masquerades as a drug. The word is derived fromthe Latin “I shall please”. Physicians throughout the ages have been confronted with patients whodemanded therapy when none was available. To please the patient, therefore, placebos wereadministered.
- These are effects which occur as a result of drug administration and have nothing to do with thepharmacological effects of the drug.
- The likelihood of placebo effects is greater in sick, anxious patients under stress than in normalvolunteers. Since 35% of patients respond to placebo, we must either compare a new drug with a placeboor with an older drug of proven value. It is not ethical to compare a new drug to a placebo if there is anolder drug of proven value with which to compare the new drug. This follows from the fact thatindividuals must not be deprived of effective therapy when conducting the trial.
Beecher placebo study
- Beecher in 1955 conducted one of the most comprehensive studies of placebo effects. He collecteddata on the placebo effect in approximately one thousand patients with a variety of conditions, namely: angina pectoris, the common cold, anxiety and tension, cough, mood changes, headache, seasickness, andpostoperative wound pain. He found satisfactory relief in 35% of patients with these conditions.
- Other conditions which have been found to be responsive to placebos are asthma, hypertension andmental depression. It is of interest that patients receiving placebo treatment have reported adverseeffects.
Design Of A Phase III Study (Comparative efficacy trial)
- Cross-Over Design
- Double-Blind Design
- We may administer a new drug to all individuals on one occasion and study the effect of the drug,and then administer an older drug (or placebo) to the same individuals on another occasion. This methodis flawed since there may be differences in the individual groups when studied on the second occasion.
- We divide the individuals in the clinical trial randomly into two groups. On the first occasion, GroupA receives new drug and Group B receives older drug (or placebo) – effects of treatments are compared. On the second occasion, Group A receives older drug (or placebo) and Group B receives new drug –effects of treatments are compared. The treatment of the two groups should be compared at the sametime in order to be valid. This type of trial is can be used in disease states which are chronic and stable. Has limited application
- Subjects assigned to different experimental groups must be assigned in a strictly random manner. Flaws have been discovered in previous trials when this was not done. The best method is to use a tableof random numbers where a sequence of digits is generated randomly by a computer.
- Consider that 24 subjects, whose initials appear below, are to be the subjects in a clinical trial. Halfof the subjects will constitute a placebo group and half will be given the new drug. The subjects arenumbered serially from 01 to 24. To fill the first group, we enter the table of random numbers at theupper left and read out two-digit numbers. Numbers greater than 24 are ignored as are numbers alreadyassigned. We carry out this procedure and place stars adjacent to 12 initials. The initials with starsconstitute one treatment group; the remaining initials constitute the second treatment group.
- In order to carry out a valid clinical trial, it should be carried out in a double-blind manner. In orderto achieve this:
- 1. The subjects should be unaware of whether they are receiving new drug or older drug (or placebo).
- 2. The clinical investigator should be unaware of whether the subject is receiving the new drug or olderdrug (or placebo).
- Such a procedure is necessary in order to eliminate bias on the part of both the subject and theinvestigator.
Design elements of a phase 3 trial.
- Study population: How many subjects are required? What are their characteristics? Are they representative of patients for whom the drug is directed? Will the results apply to both men and women?
- Comparator: Placebo or best standard of treatment?
- Random assignment of preselected subjects to treatment groups.
- Outcome: What is being measured? Is it valid? Is it an objective or subjective measure?
- Blinding: Double-blind or not?
- Control: All elements of the trial must be controlled
Assessing Reports on Clinical Trials
With the above background, you should be in a position to assess a report on a clinical trial asfollows. One should ask the following questions: (10)
- 1. What question is the study designed to answer?
- 2. How were the patients assigned to test and control groups?
- 3. How were they selected?
- 4. How was the study designed to minimize patient and observer bias?
- 5. Who makes the observations?
- 6. Is there a clear definition of the desired therapeutic response?
- 7. Is the therapeutic response to be measured by objective or subjective criteria?
- 8. Have the data been subjected to statistical analysis?
- 9. Has the study answered the question that was initially posed?
- 10. Were the patients selected for the trial typical of those for whom the drug is now recommended? If adrug has been tested in a male population only, is it recommended for both men and women or formen only?
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