Biomarkers

Question 1

What is a biomarker?

Answer 1

1. A biomarker is any sign of biological process that can be objectively measured
2. Biomarkers indicate when and to what extent a physiological process is taking place and what is going wrong in the body of a sick person
3. Biomarkers can be used both for diagnosis and for monitoring the success of a therapy
4. Biomarkers can be measured in bodily fluid (e.g. blood or urine) or via medical imaging testing (NIH, 2001)
5. A biomarker can be anything that reflects a biological process from genetic testing to imaging tests

Question 2

What are 2 types of biomarkers?

Answer 2

1. Disease-related
2. Drugs-related

Question 3

What is a diagnostic biomarker?

Answer 3

It is a disease-related biomarker
It tells if a disease already exists

Question 4

What is a prognostic biomarker?

Answer 4

It is a disease-related biomarker

It tells how such a disease may develop in an individual case regardless of the type of treatment

• Indicates the likely course of the disease in an untreated individual.

Question 5

What is a predictive biomarker?

Answer 5

It is a disease-related biomarker

It indicates of probable effect of treatment on patient

Identifies subpopulations of patients who are most likely to respond to a given therapy.

Question 6

What is a pharmacodynamic biomarker?

Answer 6

A type of drug-related biomarker

It measures the effects produced by a drug that may or may not be directly related to the progression of the disease

It can guide dose selection

Question 7

What are Surrogate End Points?

Answer 7

A type of drug-related biomarker

Biomarkers which can measure drug efficacy, and there is a strong correlation between the biomarker and the clinical outcomes

If a treatment alters the biomarker, which has a direct connection to improved health, the biomarker serves as a surrogate endpoint for evaluating clinical benefit.

Question 8

How to check validity of a biomarker?

Answer 8

Testing its

1) Accuracy of a biomarker test is best expressed in terms of its sensitivity and its specificity.

2) Sensitivity: detection of disease when disease is truly present

3) Specificity: recognition of the true absence of disease

A good biomarker for clinical use needs a good sensitivity and a good specificity

Question 9

What are some discussed biomarkers for psychosis?

Answer 9

1. Cortisol (CAR higher but during the day elevation is also present in depression), jnot amazing for prognosis (who will develop psychosis) but okish for predictive (who will be a responder vs non-responder)
2. Pituitary volume
3. Immunoactivity response (cytokine levels) = the same pattern in depression
4. IL-6 as a biomarker as a predictive (who will be a responder vs non-responder)
5. Brain cortical gamification (responders vs non-responders)
6. Brain images (PET) for drug-dev