Production, Recovery and Bioequivalence of Human Insulin and other Biopharmaceuticals from Transgenic Oilseeds

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1 Production, Recovery and Bioequivalence of Human Insulin and other Biopharmaceuticals from Transgenic Oilseeds Translational Seed Biology: From Model Crop Systems to Crop Improvement UC Davis Symposium September 17-20, 2007 Joseph Boothe and Maurice Moloney SemBioSys Genetics Inc Calgary, Canada

2 The promise of plant made pharmaceuticals First reports of the production of mammalian proteins in plants appear in the literature in the late 1980 s Concept of Plant Molecular Farming harnessing the potential of plants as biological factories The questions: - Can it be done technically? - Will it be possible to meet pharma manufacturing standards? - Is it economically feasible?

3 Why plants? Advantages of plant systems: Higher capacity production and lower production costs for bulk protein Economical Manufacture of large volume products Seed-based expression systems: Seeds have evolved as natural storage organs with high capacity for protein Low hydrolytic environment provides for stable storage Enables production to be decoupled from processing

4 Testing and production vehicles Arabidopsis Well-characterized, model oilseed Small size and easily maintained for simplified production in growth facilities Easily transformed through floral dipping Rapid cycling: - Expression results in approximately 3 mos. - Sufficient protein for biochemical / functionality testing in 6 mos. Safflower Safflower: Carthamus tinctorius, Family: Asteraceae Origin: Central Asia Semi-arid regions of Asia, Mexico, Australia and North America Advantages for PMP production: Low production acreages (200,000 acres in N. America, forward contracted) Predominantly self-pollinating Few weedy relatives found in the Americas Poor volunteer, low seed dormancy, low vegetative dispersal

5 Targeting for optimal expression Adapted from: Figure 1.14 Biochemistry and Molecular Biology of Plants 2000; Eds., Buchanan, Gruissem, Jones

6 Seed oilbodies Cross-section of safflower seed

7 Targeting and capture of recombinant proteins on oilbodies

8 Partitioning recombinant proteins using oilbodies Coomassie Stained Protein Gel roleosin-fp Oleosins

9 Proof of Principle with Human Growth Hormone

10 Expression of hgh in Arabidopsis A MWt. (KDa) Std wt wt hgh Fusion hgh (A) Coomassie-stained SDS- PAGE of oil body preps and aqueous phase (AP) from hgh transgenic Arab. seed 10 B MWt. (KDa) Std wt wt hgh Fusion hgh (B) corresponding Western blot probed with monoclonal anti-hgh antibody

11 Characterization of seed-derived hgh N-terminal sequence analysis of product obtained from cleavage: N-terminal of hgh 4252 cleavage product 4253 cleavage product Phe-Pro-Thr-Ile-Pro Arg-Phe-Pro-Thr-Ile-Pro Gly-Ser-Phe-Pro-Thr-Ile-Pro Oilbody associated and cleaved hgh product shown to bind soluble receptor in immunofunctional assay.

12 Cumulative Weight Gain (g) Bioactivity In vivo: Growth studies in little mice Cumulative Gain - SemBioSys Study 4 (10 mice per group) Day Unmanipulated Humatrope IP Plant-derived hgh IP Sterile Water IP Recombinant plant-derived hgh delivered by intraperitoneal (IP) injection resulted in statistically significant weight gain of little mice versus control (sterile water IP) similar to results obtained with pharmaceutical grade rhgh (Humatrope).

13 hgh expression in safflower Coomassie blue stained gel of oilbody proteins from T1 safflower lines expressing rhgh.

14 Production of Human Insulin in Plants

15 Why insulin? Diabetes a global epidemic: 246 million cases (20 million in US alone, 5.1% of the population aged 20-79) Together with complications (e.g. kidney and cardio-vascular disease, blindness, amputations) constitutes one the largest health care problems in industrialized countries Need vs. Consumption: Developed world with 20% of the diabetic population consumes 70% of the world s insulin

16 Insulin volumes 16,000 kg 6,000 kg

17 Expression construct Construct LB Pha P Ins FP Pha T Ubi P PAT Ubi T RB Fusion Protein Insulin insulin expression: under β-phaseolin promoter/terminator selectable marker: pat gene under ubiquitin promoter/terminator for PPT resistance transformation: into Agrobacterium EHA101 then into the plant using the flower dipping method (Arabidopsis) or infection of explants (safflower) post-extraction maturation of insulin: functional insulin (5.7 kda) generated by in vitro processing of fusion protein

18 Insulin expression in Arabidopsis ER Apoplast Oilbodies Gel Blot Gel Blot Gel Blot Coomassie blue stained gels and western blots (anti-insulin mab) of total seed protein

19 Insulin expression in safflower Expression screen of individual T1 seeds Insulin accumulation to levels of >1% of total seed protein

20 Insulin - chemical equivalence Electrospray Mass Spectrometry Commercial pharmaceuticalgrade insulin: Molecular mass 5807 Da Safflowerderived insulin: Molecular mass 5807 Da V8 Peptide Digest

21 % Initial Blood Glucose % Maximum Bound Insulin in vitro and in vivo functionality Insulin (ng/ml) IC 50 (ng/ml) Insulin Receptor Binding Humulin-R USP Insulin Insulin (SemBioSys) Saline 80 Insulin Tolerance Test Minutes Post Injection error bars = +/- SEM

22 Scale-up ~ 1ton of seed per acre Pilot scale process

23 Regulatory framework Product regulatory: FDA and EMEA have both published guidelines on the manufacture of biologics in plants Provided established standards of quality are met there are no barriers to the approval plant-made products Challenges: e.g. dealing with variation in expression, platformspecific impurities, etc. Environmental regulatory (field production): Need to meet regulatory requirements and address public concerns regarding containment of transgenic crop through: - Judicious selection of production host - Developing and implementing rigorous procedures for field production (GMP starts in the field!!!)

24 Concluding remarks Considerable progress has been made on the technical front with the demonstration that plants can produce biopharmaceutical proteins at commercially-relevant levels With proper attention to quality there is a clear path forward for approval of these products Work is proceeding on demonstrating that plant-based systems can deliver on the economics. Product selection key: - Capitalize on the advantages of plants by focusing on high volume products where COGs is important. - Initial focus on well-characterized proteins may speed development Success will transform the way some drugs are made and offer real socio-economic benefits.

25 SemBioSys Cory Nykiforuk, Phil Kuhlman, Yin Shen (Biochemistry) Chao Jiang (Arabidopsis) Indra Harry (Safflower) Maria Meier (Molecular Characterization) Liz Murray & Amanda Bodero (Bioassays) Brent Pollock (Process Development) Rick Keon (Plant Growth Operations) University of Calgary Joe Goren (Dept. Biochemistry and Molecular Biology, Medicine) Doug Morck (Dept. Biological Sciences, Science / Veterinary Medicine)