Selected Products of Bioprocessing

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Selected Products of Bioprocessing
digging a bit deeper
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Farmaceuticals

• genetic modification of animals
• production of therapeutic proteins in milk, eggs
  or blood

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Demand?

• gt100 protein based drugs are in advanced phases
  of clinical trials
• production facilities cost 200m-400m
• goats and cows most promising alternative

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Goata be kidin

• animals as bioreactors
• milk loaded with proteins
• GTC Biotherapeutics, Massachusetts engineered
  (transgenic) goats, producing 14 varieties of
  therapeutic proteins
• 18 months/goat
• 100m/herd

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Goat versus Cow

• 18 months to make transgenic goat
• 3 years/cow
• 2 L/day milk/goat
• 20 L/day/cow

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Cost?

• mammalian cell culture 150/gram
• transgenic animals 2/gram
• dont believe everything you read

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GTC goals

• recombinant human anti-thrombin III (rhATIII),
  anti-coagulation protein found in blood
• 250m worldwide market
• presently 10m/year sold in US
• treat hereditary difficiency

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GTC goals

• recombinant human serus albumin (rHSA)
• demand 400 tons/year
• presently isolated from plasma
• supply and safety concerns
• bioreactors unrealistic given demand

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Third product?

• malaria vaccine MSP-1 from goat milk
• 8 goats produce enough vaccine to inoculate 20
  million people

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• Pharming Group, Leiden, Netherlands
• C1 inhibitor (C1 INH) for hereditary angioendema
  (lack inhibitor protein)
• C1 is proenzyme in serum complement pathway,
  which is controlled by inhibitor
• being produced from wabbits

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Other Pharming products

• fibrinogen and collagen produced in cows
• used in wound healing and cosmetics
• lactoferrin, an anti-infective
• 20 cows can produce world fibrinogen supply (150
  kg)
• cow producing 10,000L milk/year generates 100 kg
  protein (10 g/L)
• fermentation process, 200-300 kg/year

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Transgenics versus bioprocess

• capital cost advantage
• 40 200m/production facility
• capital costs in farming are considerably less
• relatively homogeneous medium

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BioProtein Technologies, Paris

• proteins from rabbit milk
• 4-5 months to sexual maturity
• gestation 1 month
• rather prolific breeders

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Rabbit versus CHO cells

• line of transgenic rabbits in 6 months
• product within year
• similar time frame to CHO cells
• 250 mL milk/day compared to 20L/cow
• 1-10 g/L recombinant protein

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Potential products

• antibodies, plasma proteins, hormones
• some success with human growth hormone and
  cellular-superoxide dismutase

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transgenic embryo
microinject transgene into fertilized oocyte
recipient female
breeding
selection of transgenic wabbit
milk extraction and purification
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• Gala Design, Middleton, WI
• focus on gene insertion using retrovirus vectors
• transfection rate 50-100 in cows, pigs, monkeys
• genes inserted into eggs before fertilization
  (transgametic), followed by in vitro culture...
  many transgenic embryos result, are fertilized
  and the rest is up to nature

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Consider the chicken!

• eggs are sealed and sterile
• protein loaded
• chickens grow fast and easier than cows
• occupies 1 ft2

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Transgenic chickens

• chimeric chickens produce 1 human antibody and 1
  mouse antibody in egg albumen
• low yields
• working on insulin and human serum albumen

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• express proteins in eggs at 1 mg/egg
• 20 mg/kg chicken (similar productivity to cow)
• laying at 5 months
• produces 600-700 eggs/chicken
• 100m chickens/rooster in 2 years
• sterile packaging
• storage without need for stabilization
• 88 protein in egg white
• 11 proteins make up 95 of egg white
• crack and separate 200,000 eggs/h/machine
• widely used in vaccine manufacture, so
  acceptable as transgenic medium
• AviGenics is expressing interferons, antibodies
  and cytokines

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Regulatory approval

• challenge
• fears of bovine spongiform encephalitis (mad cow)
  as example
• also fears of prions
• some argue that milk producing animals do not
  harbour human viral pathogens

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Other cost considerations

• raising animals costs 30-80 less than cell
  culture
• 300,000/transgenic cow
• 30,000/transgenic pig
• cloning costs 100-200K/animal
• related facilities 5-7m
• but lifetime or production, plus offspring