An over view of the biopharmaceutical discovery process

Robert Rehfuss, PhD

A Simplified Process Map for Biopharmaceutical Discovery

Target Identification

Laying the Groundwork

Cranking up the Band

Delivering the Goods

2-5 years

Step 1: Target Identification • A “Target” is the molecule (receptor, enzyme, etc.) that you

want to activate/inhibit so as to effect a disease process

– Choosing a target is the single most important step in the process• Good targets do not always result in therapeutic agents• Targets that don’t effect the disease biology cannot result in effective

therapeutic agent ever, regardless of time/resources committed to project– Requires extensive and detailed knowledge of:

• Specific disease area biology including pathophysiology • Existing therapy for a disease including pros/cons of current therapies• Current scientific literature directly (but also indirectly) related to disease

– Most targets are widely known and well picked over• Capitalizing on new science (new targets, new approaches) requires speed

to gain an advantage over competition

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Leading Causes of Death for All Males and Females United States: 2003*

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Source: CDC/NCHS and NHLBI. *Preliminary

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Fibrous Cap

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Thrombus Formation

Non-ST-Segment Elevation Acute Coronary Syndrome (ACS)

ST-Segment Elevation Acute Coronary Syndrome (ACS)

Old Terminology:

NewTerminology:

Thrombus Formation and ACS

Gachet , C. (2006) Ann. Rev. Pharmacol.Toxicol.

Key Role of Platelet Aggregation in Arterial Thrombus

Trends in Age-Adjusted Prevalence of Health Conditions, U.S. Adults Ages 20-74 NHANES:1971-74 to 1999-2000

Source: Ann. Rev. of Nut. July 2004. Vol.24: 401-431

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Overweight/Obesity Hypertension High Blood Cholesterol

Biology beats Marketing every time!

An innovative and effective cure for a rare disease will make more money than still another anti-hypertensive

Step 2: Laying the Groundwork • After choosing a target, two key strategic questions need

answers:– Is the available data supporting the target sufficient to convince

others to move a potential agent into ($$$) clinical trials?• Usually not. What additional studies need to be preformed? Who does

them? What reagents (and from what source) are needed to enable those studies? What animal models will be used to demonstrate efficacy of the final therapeutic agent for the FDA?

– What type drug will be most likely to produce both a clinical candidate and a profitable therapeutic agent?

• Pros/Cons of biopharmaceutical vs. pharmaceutical approaches– Delivery Route, Cost of Goods, Likelihood of Success

• Choice effects downstream strategy as different types of assays need to be developed to screen candidates

– Recombinant production of target as either antigen or reagent for assays– Development of primary assay (ELISA vs. Binding vs. other)

Step 2: Laying the Groundwork (cont’d)

• And one tactical question:– How will the activity of potential candidates be measured?

• Binding or Enzyme assays?• Cell based assays?• Where do the reagents come from?• Who designs the assays? Who performs the assay(s)?

Monoclonal Antibody Generation

100’s of mAb to screen

Recombinant production required

ELISA

Recombinant production required

Step 3: Cranking up the Band(BioPharmaceuticals)

• Assembling a team of scientists to sort through the different molecules to find the specific one with the right mixture of properties

– Affinity for Target• ELISA, HTRF, SPR (Biacore), BLI (Octet RED)

– Ability and potency to inhibit desired biology• Cell or plasma based signaling assays

– Pharmacokinetics/ Pharmacodynamics (PK/PD) – Other Biophysical Properties

• Expression yield (system dependent)• Melting temperature and behavior

– Low temperature, irreversible melting behavior very undesirable• Aggregate formation on storage

Properties can be “tweaked” by addition of point mutations at this step

Step 3: Cranking up the Band(Pharmaceutical)

• Assembling a team of scientists to sort through the different molecules to find the specific one with the right mixture of properties

– Affinity for Target• ELISA, HTRF, SPR (Biacore), BLI (Octet RED)

– Ability and potency to inhibit desired biology• Cell or plasma based signaling assays

– Pharmacokinetics/ Pharmacodynamics (PK/PD) • Optimization of dosing formulations

– Other Biophysical Properties• Solubility, Crystalline Behavior, Stability

– Key parameters for manufacturing

Properties “tweaked” by subtle variation of chemical structure

New compound synthesis by Chemistry

Tested in Secondary Assays for potential in vivo activity•Screening assays for target activity•Screening assays for PK potential•Screening assays for potential liabilities

Doesn’t meet criteria

Tested in Primary Assays for target potency/selectivity

Generic Triage Scheme

In vivo testing :•PK/PD (ADME)•Efficacy (Biology) &

Toxicity Assessment

Candidate declaration

Step 4: Delivering the Goods• Complete characterization of a pre-clinical candidate in non-

human species. Documentation produced with an eye on the data required by FDA for filing of IND/BLA – Production of material under GMP (or sometimes near-GMP)

conditions• Extensive testing in disease models to demonstrate likelihood of clinical

efficacy– If mAb doesn’t cross react with non-human model then 2 completely

separate programs needed• Extensive PK/PD testing in multiple species to try and anticipate human

PK/PD• Toxicology studies (high dose and prolonged exposure in at least 2

established species (rat, mouse, dog, NHP) one of which may be rodent• Final determination of expression system and protocol to be used for GMP

production

– FDA will only accept data for IND/BLA if material is GMP and studies are carried out under GLP conditions.

• Studies with near-GMP material need replication if they are to be reported

Questions?