Lec. 23 - Drug Design 2: Clinical Trials Flashcards

1
Q

Why do we need to do human trials even after animal models?

A

Due to

  • Human differences
  • Species variability
  • Differences in pharmacokinetics and pharmacodynamics
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2
Q

What part of drug development is most expensive?

A

Clinical trials

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3
Q

What are the 3 questions clinical trials aim to answer?

A

Is it safe?

Does it work?

Is there a better alternative already on the market?

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4
Q

What are the 3 phases to clinical trials?

A

Phase 1: Human safety/Pharmacokinetics:
20-80 healthy volunteers

Phase 2: Evaluate effectiveness/Side Effects:
100-300 patient volunteers (who have illness)

Phase 3: Verify effectiveness/Long time use:
1000-3000 patient volunteers

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5
Q

Describe clinical trials - phase 1

  • Goal
  • Population
  • Duration
  • Process
A

Goal:
Test human safety

Population:
20-80 healthy people, monitored carefully

Duration:
Days or weeks

Process:
-Starts with pharmacokinetics monitoring.
-If safe, expands to safety testing
(starting at low doses until therapeutic dose reached)

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6
Q

Describe clinical trials - phase 2

  • Goal
  • Population
  • Duration
  • Process
A

Goal:

  • Test if drug works
  • Evaluate side effects

Population:
100-300 patients with disorder

Duration:
Weeks or months

Process:

  • Check for pain in patients
  • Expand pharmacokinetics knowledge to range (poor metabolizers, poor responders)
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7
Q

Describe clinical trials - phase 3

  • Goal
  • Population
  • Duration
  • Process
A

Goal:

  • Verify efficacy
  • Study long term effects

Population:
1000-3000 patients

Duration:
Several years

Process:

  • Verify adverse effects in long term use
  • Find even rarer side effects (larger pool of participants)
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8
Q

Explain 2 methods of clinical trial

A

Parallel design:

  • To test vs drug on the market
  • Have two concurrent groups testing new drug vs one on market

Crossover design:

  • 2 concurrent groups testing both market and new drug
  • Market (washout) then new
  • New (washout) then market
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9
Q

Name and explain 2 things to control for

A

Lifestyle:

  • Important effect on patient well being
  • Ex. have 4 groups for diabetes experiment (placebo vs. new drug vs. market drug vs. intense lifestyle change)

Patient Compliance:
-Mortality hin people will less than 80% complicance

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10
Q

Why do short term drugs still need to be monitored in long term?

A

See if the treatment is consistent (ex. is there an ulcer relapse)

ex. lorezepam (benzodiazepine) ‘pain relief’ effects wear off after a few weeks (as what was being felt was sedation)

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11
Q

What good study demonstrated the placebo response?

A

Doctor coming in with treatment vs machine administering hidden treatment.

Doctor yielded higher pharmacological response due to expectancy related effect

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12
Q

Describe an example of behavioural conditioning

A

Pill on its own -> brain activity

Pill + neutral stimulus -> brain activity (acquisition)
Neutral stimulus (after conditioning) -> brain activity (evocation)

Conditioned response to neutral stimulus

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13
Q

Give an example of drug resistance being something to watch for in clinical trials

A

If your drug for a tumor were only somewhat effective, you could end up with a drug that whittles a tumour down to a few, drug-resistant cells that could then come back stronger.

It is important to monitor long term to ensure tumor resistance doesn’t occur

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14
Q

What needs to be done after phase III of a clinical trial?

A

Data needs to be evaluated for efficacy and safety (NDA, health Canada, etc.)

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15
Q

Name 4 ways NDA reviews information from clinical trials

A
  • Characterize exposure database (check that random assignments occurred)
  • Identify adverse effects
  • Estimate risk of side effects
  • Identify risk factors (ie patient characteristics)
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16
Q

What are orphan drugs? How are they funded?

A

Orphan drugs are made for specific diseases affecting a small number of people, so not much profit to be made.

Usually funded by governments

17
Q

What is main reason for drug failure in clinical trials?

A

Pathogenesis of treatment clearly was incorrect! Drugs did not really target problem

18
Q

What are 3 important factors for a drug going into market

A

Needs to be:

  • cheap
  • stable (no disintegrating on shelf)
  • Soluble (ideally absorbed in pill. If not, injection)
19
Q

What’s a possible solution to short half-life of drug?

A

Design a slow-release pill to take everyday

20
Q

What is clinical phase 4?

A

Released to public, but continuously monitored for safety and efficacy.

INCREDIBLY uncommon side-effects can be found (since drug is being put out to millions of people)

Uncommon adverse drug reactions (ADR) can be observed (since 1/1000 reaction would need 3000 cases to have a 95% chance of observing it

21
Q

What demographic is particularly observed during phase IV?

A

Elderly and young (as they are usually omitted from clinical trials)

22
Q

What happens to a drug if there are serious risks, but still has therapeutic benefits?

A

Black box warning -> UTMOST caution must be used when taking drugs

23
Q

What are the 3 classes of clinical trials?

A

Class3:
Normal

Class2:
Faster (ex. life-threatening diseases)

Class1:
Even faster (emergencies)
24
Q

Describe a success of MAB therapy in 2018.

A

Pembrolizumab won the nobel prize for immunotherapy against cancer.

Tumor cells can often utilize checkpoint proteins to inhibit T-cells (ex. PDL1 binds at PD1 receptor)

Pembrolizumab targets PD1, allowing T-cells to kill cancer.

25
Q

Give an example of a drug successfully treating cancer

A

Ibrutinib treats chronic lymphocytic leukemia

Targets btk enzyme, which allows malignant B-cells to overly express.

Thus, ibrutinib blocks B-cell proliferation

26
Q

What other functions can MAbs have to combat cancer?

A
  • Deliver radioisotope to tumor cells
  • Block Growth Factor receptors on tumor cells
  • Used to identify tumor cells and give a more accurate prognosis
27
Q

MAB implications for migraines?

A

Calcitonin-gene related peptide (CGRP) often implicated in migraines.

Mabs can be injected once a month to block CGRP and prevent migraines.

28
Q

What treats Hep. C

A

Sofosbuvir

29
Q

What drugs can help heart failure?

A

Heart is too weak and can’t pump blood

Natriurietic and vasoactive peptides usually lower BP, but they are broken down too fast by neprilysin

New drug targets neprilysin