Biologics

Question 1

Biologics FDA definition

Answer 1

-Therapeutic made from or containing human/animal cells

Question 2

Advantage over small molecule drugs

Answer 2

-Often target systems with greater specificity -Safer/more practical means of extraction - Greater yields - Greater clinical efficacy

Question 3

Delivery

Answer 3

• Mostly IV, SC, IM - some inhalation -Some topical (PGDF for skin ulcers)

Question 4

Rationale for mABS

Answer 4

-Antibodies are produced to bind to specific antigens - Antibodies made for a drug target will thereby be potent and selective in binding - similar to an antigen but no immune response is elicited

Question 5

polyclonal vs monoclonal

Answer 5

polyclonal: bind many different antigens due to variation in the variable regions mAB: single antibody with a specific variable region, binds to only one antigen

Question 6

Hybridoma Cells

Answer 6

• Arrise from the fusion of immortal myeloma cells with antibody producing ß-Lymphocytes
  1. mix antibody producing spleen cells from mice and myleoma cells
  2. Select and grow hydrid cells only
  3. Seperate hybrid cells and allow them to proliferate
  4. Screen for desired antibodies (using antigens)

Question 7

Adalimumab

Answer 7

• Fully human mAb
• Directed to tumor necrosis factor alpha
• SC injection approved for the use of inflamatory related conditions

Question 8

Phage-display library

Answer 8

• A phage is a virus which infects bacteria
• Phage makes antibody of interest
  1. Cells from infected subjects takem
  2. Non specidfic RNA isolated and cDNA made
  3. Heavy and light chain genes isolated and amplified using primers
  4. Heavy and light chain regions put into an expression vector (phage) is then transfected into CHO cells which produce the active ingredient
  5. protein is selected using antigen

Question 9

Insulin

Answer 9

• Initially produced as an extract of bovine and porcine pancreatic tissue followed by chromatographic purification. Issues with immunogenicity due to disparities in amino acid sequence
• Subsequently expressed as A and B chains in seperate recombinants and then purified under oxidizing conditions which favoured the formation of disulfide bonds
• Contemporarily expressed as a single chain of pro-insulin which is purified and then undergoes proteolytic cleavage of the c-terminus in vitro

Purification processes:

• Gel filtration
• Ion exchange
• reverse phase

Specific aminio acids have been altered to change the pharmacokinetic profile of the drug

Question 10

Adapted mABS

Answer 10

• Antibody drug conjugates: toxin is attatched and deliveried directly to the target cells
• GLycoengineered; specifically modified to help activate immune system more effectively
• bispecific: can recogognize two targets stimultaneously, can be ued to bring them in close proximity

Question 11

DNA and RNA based therapy rationale

Answer 11

Gene therapy can replace defective genes and thereby increase protein expression to cure disease

OR

Block protein expression using anti-sense-RNA/DNA to block mRNA (also siRNA/RNAi)

Question 12

Comparrison of ASO and siRNA

Answer 12

1. ASO is single stranded and finds its target alone whereas siRNA is a duplex which assosciates with the passenger strand and is then guided to the target

Question 13

ASO structure and function

Answer 13

• DNA or Ribose sugar backbone
• Base pairs make interactions with DNA (T or U may be used)
• Ribose sugar: often modified to reduce RNAase interference
• Phosphodiester: Modified to increase stability(PO replaced with PS) and other groups to remove charge and/or increase stability