Biologics vs Small MW NCEs What s the difference? Challenges in pre-clinical development of biologics Peter Lloyd Joint Conference of EU Human Pharmacological Societies and 20 th Anniversary of AGAH 31 March 2011 Acknowledgements: Jennifer Sims, Phil Lowe, Sebastian Spindeldreher, Andrew Warren
Protein therapeutics biologics Current generation recombinant proteins, binding proteins, cytokines; pegylated proteins: antibodies (mabs), antibody fragments (e.g. Fabs), antibody drug conjugates (ADCs) Next generation? above proteins with non-natural amino-acids / post-translational modifications (eg altered glycosylation pattern), nanobodies, bi-specific antibodies, new scaffolds...... Slide 2 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Monoclonal antibodies vs NCEs: mab New Chemical Entity 150,000 dalton 200-500 dalton Biological production process heterogeneous (post-translational modifications) High species selectivity (affinity / potency) Multi-functional target binding, Fc effector function, FcRn binding Toxicity largely on target mediated exaggerated pharmacology Slow clearance; long half-life (days) infrequent dosing (weekly / monthly)? Target can affect PK behaviour (Target Mediated Drug Disposition) Drug-Drug Interaction few examples and mostly PD related Immunogenicity sometimes observed Chemical production process - homogeneous Generally less selective Single target Toxicity often off target mediated Rapid clearance; short half-life (hours) frequent dosing (daily) Mostly linear PK; non-linearity from saturation of metabolic pathways DDI many examples and metabolic and/or PD related Immunogenicity rarely observed Slide 3 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Outline of the presentation: PK-PD behaviour of mabs - inherent IgG characteristics - binding models and Target Mediated Drug Disposition Developing an integrated bio-analytical strategy - PharmacoKinetics - PharmacoDynamics (target ) - Immunogenicity Selection of appropriate starting doses for early clinical testing - FDA guidance 2005 - NOAEL / (PAD) MABEL Summary Slide 4 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
A simple mab PK model mab iv dose elimination mab limited volume of distribution ~ 7L slow clearance t ½ ~ 20 days (human) FcRn (tight binding at ph6) protects IgG from degradation & explains long serum half-life Roopenian and Akilesh. Nature Reviews Immunology 2007; 7: 715 Slide 5 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Mouse, rat and monkey FcRn recognise human IgG NB - binding affinity of human IgG to mouse FcRn is 10x higher than to human FcRn rat cynomolgus monkey mouse - inherent human IgG kinetics scales reasonably well across species - NB when target mediated disposition is absent Slide 6 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
lower FcRn binding affinity Engineered proteins may have altered FcRn binding fusion proteins chimeric mabs human mabs - cept - iximab - umab shorter half-life Suzuki T et al: Importance of neonatal FcR in regulating the serum half-life of therapeutic proteins containing the Fc domain of human IgG1: a comparative study of the affinity of monoclonal antibodies and Fc-fusion proteins to human neonatal FcR J Immunol 2010; 184: 1969-1976 Slide 7 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Ligand binding model (closed system) mab + mab complex at equilibrium: K d = [mab]. [] [mab- complex] Assumptions: - static system; no turnover of, no loss of mab to distribution and elimination, instantaneous equilibrium Slide 8 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Ligand binding model (closed system) TGN1412 mab + mab complex K d = 1.88 nm dose 0.1 mg/kg MW 150,000 plasma volume 2.5L TGN1412 = 18.7 nm (immediately post-dose) Tcell 1.9 x 10 6 ml -1 CD28 / cell 150,000 CD28 = 0.95 nm at baseline Receptor occupancy (%) 100 80 60 40 20 Dose (mg/kg) Assumptions: - static system; no turnover of, no loss of mab to distribution and elimination, instantaneous equilibrium Slide 9 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011 0 0.0001 0.001 0.01 0.1 1 10
A simple mab PK-PD model input mab + mab complex dose elimination mab slow clearance elimination rapid clearance Soluble target: mab- complex tends to take on the elimination characteristics of the mab elimination mab complex Cellular target: mab- complex tends to take on the elimination characteristics of the (TMDD apparent) Slide 10 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Typical mab PK-PD model(s) Lowe PJ et al: On setting the first dose in man: Quantitating biotherapeutic drugtarget binding through PK and PD models Basic & Clin Pharmacology & Toxicology 2009; 106: 195-209 Slide 11 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Example 1: mab against cell surface anti-cd11a mab Raptiva (efalizumab) - rapid clearance of mab-receptor complex - high doses saturate target binding capacity with a return to normal IgG kinetics mab complex increasing dose: change in IgG kinetics (TMDD) Target Mediated Drug Disposition increasing dose: increases duration of effect Joshi et al An overview of the pharmacokinetics and pharmacodynamics of efalizumab: a monoclonal antibody approved for use in psoriasis J Clin Pharmacol 2006; 46: 10-20 Slide 12 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Concentration (linear scale) nm Concentration (log scale) nm Example 2: mab against soluble (MCP-1) mab complex - slow elimination of mab- complex - accumulation of total - rapid turnover of - rapid saturation of binding capacity - long half-life total mab short duration of effect Accumulation inactive complex 1 x 0.1 mg/kg 2 x 0.3 mg/kg total total mab total mab free (not measured) total free mab (not measured) Time (days) Time (days) Slide 13 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Example 3: mab against soluble (IL1-b) - slow elimination of mab- complex - saturable accumulation of total mab complex - long half-life total mab; long duration of effect Accumulation inactive complex Measured ACZ885 (2 x 10mg/kg) Measured total IL-1β Slide 14 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Example 3: mab against soluble (IL1-b) mab complex Accumulation inactive complex Measured total ACZ885 increasing dose: no change in IgG kinetics Simulated free IL1-b increasing dose: increases duration of effect 10 mg/kg 3 mg/kg 1 mg/kg 0.3 mg/kg 0.1 mg/kg 0.1 mg/kg 0.3 mg/kg 1 mg/kg 3 mg/kg 10 mg/kg Slide 15 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Scalable components of the PK-PD model: Inherent pharmacokinetics of the mab and clearance of the mab- complex: - PK of monoclonal antibodies will generally follow typical IgG behaviour and scale reasonably well to man and/or exhibit Target Mediated Disposition and be dependent on the amount of target present and its rate of turnover Binding affinity and potency against the target : - species differences understood during characterisation of the mab Expression and turnover of the : - key drivers of the extent and duration of response; can affect PK behaviour - once maximum binding is achieved then increasing the dose will primarily increase the duration of response: are SAD/MAD designs appropriate for early clinical development? - species differences and differences between healthy individuals vs disease often not well understood Slide 16 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Outline of the presentation: PK-PD behaviour of mabs - inherent IgG characteristics - binding models and Target Mediated Drug Disposition Developing an integrated bio-analytical strategy - PharmacoKinetics - PharmacoDynamics (target ) - Immunogenicity Selection of appropriate starting doses for early clinical testing - FDA guidance 2005 - NOAEL / (PAD) MABEL Summary Slide 17 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Bioanalytical strategy - PK Free- bioactive mab Total mab sandwich ELISA anti-human IgG mab (drug) anti-human IgG mab (drug) anti-human IgG sandwich ELISA (pre-clinical only) mab (drug) competitive ELISA protein digestion bridging ELISA mab (drug) protein LCMS unique signature peptide Slide 18 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Bioanalytical strategy PD (soluble ) total (target capture) anti Ab2 mab (drug) anti Ab1 + + sandwich ELISA endogenous binding protein free anti Ab4 anti Ab3 sandwich ELISA mab (drug) endogenous binding protein Technically challenging: detection of total (increasing) in the presence of drug and endogenous binding protein (if relevant) careful selection of capture and detection reagents (Ab1 and Ab3 Technically very challenging: detection of free (decreasing) in the presence of increasing concentrations of total specificity and sensitivity (LLOQ) Slide 19 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Bioanalytical strategy - immunogenicity Biacore Bridging ELISA mab (drug) labelled ADA ADA mab (drug) mab (drug) non-neutralising neutralising non-neutralising neutralising Consequences of immunogenicity: - increase in clearance of mab (immune complexes) - decrease in capacity for target binding (neutralising immunogenicity) - influence on PK and/or PD assays integrated assessment? Slide 20 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
anti-human interleukin mab [µg/ml] Serum concentration rel. Response Unit [RU] Example 4: mab against cell surface (receptor) Single dose 10 mg/kg i.v. n=3 animals 300 PK profile 1400 1200 Immunogenicity 200 800 600 100 400 200 0 0 10 20 30 40 50 Time [day] 2001 2002 2003 competitive ELISA mab (drug) 0-200 0 10 20 30 40 50 Time [day] 2001 2002 2003 Biacore ADA mab (drug) Slide 21 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Serum concentration [ug/ml] Rel Response Untis [RU] Example 4: mab against cell surface (receptor) Three doses 100 mg/kg i.v. days 0, 7, 14 (n=3 animals) 0 100 400 350 300 250 PK assay mab (drug) 10 200 150 bridging ELISA 1 100 50 Immunogenicity 0 0 0 20 40 60 80 100 120 ADA Days - bridging ELISA overcomes limitations of competitive ELISA to measure exposure to drug in presence of ADA response - rapid clearance of drug due to nabs and/or rapid clearance of immune complexes Slide 22 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011 Biacore mab (drug)
Outline of the presentation: PK-PD behaviour of mabs - inherent IgG characteristics - binding models and Target Mediated Drug Disposition Developing an integrated bio-analytical strategy - Pharmacokinetics - Pharmacodynamics (target ) - Immunogenicity Selection of appropriate starting doses for early clinical testing - FDA guidance 2005 - NOAEL / (PAD) MABEL Summary Slide 23 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
FDA guidance: 2005 Step 1 Determine No Observable Adverse Effect Level (NOAEL) Step 2 Step 3 Convert NOAEL to a Human Equivalent Dose (HED) - generally normalised to body surface area (low MW NCEs) - mg/kg normalisation recommended for proteins >100K daltons Select HED from the most appropriate species - additional factors: metabolism, receptors, binding epitopes - default: most sensitive species (lowest HED) Step 4 Apply a safety factor (>10-fold) to give a: Maximum Recommended Starting Dose (MRSD) Step 5 Adjust MRSD based on the pharmacologically active dose (PAD) Slide 24 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
FDA guidance: 2005 Pro simple to use supported by historical evidence (mainly conventional NCEs) Con implicit in guideline primary focus: NOAEL (steps 1-4) secondary focus: pharmacologically active dose (PAD) over simplified scaling to man focus on dose not exposure one algorithm fits all step 5 often ignored Slide 25 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
NOAEL and MABEL (PAD) NOAEL No Observable Adverse Effect Level FDA highest dose level that does not produce a significant increase in adverse effects an effect that would be unacceptable if produced by the initial dose of a therapeutic in a phase I clinical trial conducted in adult healthy volunteers MABEL - Minimal Anticipated (Acceptable) Biological Effect Level minimal exposure / dose level that is anticipated to produce an acceptable biological effect an effect that would be considered acceptable if produced by the initial dose of a therapeutic in a phase I clinical trial Slide 26 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
NOAEL and MABEL MABEL NOAEL Mueller et al The minimum anticipated biological effect level (MABEL) for selection of first human dose in clinical trials with monoclonal antibodies Current Opinion in Biotechnology 2009; 20(6): 722-729 Slide 27 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Example 5: target suppression in safety assessment mab complex humanised mab; high affinity against soluble target Accumulation inactive complex K d man < cynomolgus monkey (~10-fold) typical IgG kinetics target can be measured in the systemic circulation at baseline and is increased in disease mab acts as a capture system : mab- complex (detected in serum) is a biomarker for suppression of free via a PK/PD model previous experience with a similar molecule (lower affinity) against the same target Slide 28 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Concentration (µg/ml) Concentration (µg/ml) (ng/ml) Concentration Concentration (µg/ml) Concentration (ng/ml) Example 5: 4wk GLP toxicology study mab complex 100 Accumulation inactive complex 10 PK-PD model: exposure and 100 total 10 100 10 PK (exposure) DOSE: 0 DOSE: 03 1 0.1 DOSE: 0 DOSE: 10 3 0 DOSE: 10 15 3 1 0.1 1 0.1 DOSE: 10 DOSE: 20 15 10 DOSE: 120 15 pre-clin exposure data conform 1 0.1 1 0.1 to a 2-compartment model DOSE: 20 0 28 DOSE: 120 56 84 DOSE: 120 0 28 56 84 0 0 Time (days) Time (days increase in total (measured) 100 100 fitted to binding model 10 10 10 1 PK-PD model allows estimation of 1 0.1 1 free (target 0 suppression) 28 56 84 0 28 56 84 0 28 56 84 Time (days) Time (days) NB: free (green) not measured 0 100 10 1 0 0 100 100 10 10 10 1 1 0 0 100 100 10 10 10 1 1 Time (days) PD (total ) Slide 29 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Serum concentration (ug/ml) Example 5: predicted exposure (PK) in man mab complex 0 Accumulation inactive complex Cynomolgus monkey PK-PD model scaled to human: 100 10 Cynomolgus monkey 120mg/kg NOAEL (observed mean data) >100-fold exposure safety margin (C max ) - IgG PK behaviour 1 10.0 mg/kg - increased target binding affinity (10-fold) 0.1 0.01 0.1 mg/kg 0.3 mg/kg 1.0 mg/kg 3.0 mg/kg 0.001 0 20 40 60 80 100 120 140 160 Time (days) Slide 30 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Concentration (ng/ml) Concentration (ng/ml) Example 5: predicted PD (effect) in man mab complex Simulation: predicted target suppression in man - pre-clin exposure data adjusted to man - binding affinity in PK-PD model adjusted to man Accumulation inactive complex MABEL predicted free 100 10 0.1 mg/kg 0.3 mg/kg Monte-Carlo simulation 100 1 1 mg/kg 3 mg/kg 10 mg/kg 10-28 -14 0 14 28 42 56 70 84 Time (days) 98 1 0.1 112 126 140 154 168 182-28 -14 0 14 28 42 56 70 84 98 Time (days) 112 126 140 154 168 182 Slide 31 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Example 5: Justification of starting dose in man Toxicology (exposure) [1] NOAEL 120 mg/kg [2/3] HED 120 mg/kg - adjust for anticipated exposure in man? [4] Apply >10-fold safety factor 12 mg/kg Pharmacology (response) [5] PAD / MABEL - justify based on pharmacology - max pharmacology achieved at 20mg/kg (6-fold lower than NOAEL) - adjust for anticipated exposure in man (0.1 mg/kg projected to give >100-fold margin) - include anticipated duration of effect - adjust for inter-species differences in affinity / potency (>50% suppression for <48h) 0.1 mg/kg Maximum Recommended Starting Dose - define anticipated safety window based on NOAEL and MABEL * 0.1 mg/kg * - NB an additional factor may be added based on uncertainty of data / prediction and relative risk Slide 32 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Benefits of an Integrated Approach Simple mathematical representation of known biology also represents components of the model which cannot be measured (e.g. low circulating level of free ) Hypothesis testing the ability to test assumptions prior to experimental design, leading to better pre-clinical and clinical studies Sensitivity analysis elements of the model which are key drivers of the desired outcome (e.g. target expression / target turnover / affinity / potency) Slide 33 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Summary: Challenges in pre-clinical development of biologics Inherent IgG characteristics make mabs attractive drug targets; however; unlike small MW new chemical entities (NCEs): target biology can affect PK behaviour of mabs / duration of action - target expression (how much and where?) and target turnover (how quickly is it replaced?) - normal vs disease, gender, species differences should be understood - other sinks (e.g. shed or decoy receptors), off target binding, endogenous binding proteins A bioanalytical strategy and appropriate tools needs to be developed - integrated interpretation of PK, target binding and immunogenicity An integrated PK/PD-(IG) approach can quickly identify appropriate dose and dosage regimen to achieve desired target suppression - influence and impact on traditional study design Slide 34 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011
Slide 35 Early Pre-Clin Dev of Biologics Peter Lloyd Berlin March 2011 Thank you for your attention