Tying Higher Order Structure with in-vitro Activity Through a Forced Degradation Study Laura Duitch Haihong Fan Wasfi Al-Azzam HOS 2013 Feb11-13 2013 Property of GlaxoSmithKline
Outline Introduction Study Design ph3 ph10 Thermal Results FTIR/Near UV ECD Spectra Quantitative Spectral Analysis SEC, cief, Biacore, Cell Based Potency Assay Conclusions
Introduction Particles Aggregates Normal Activity Fragments
Study Design Bulk Batch IgG Stres ss Condit tion BDS BDS BDS 100 100 100 mg/ml mg/ml mg/ml Acidic; ph 3; Basic; ph10 Thermal 1M HCl 1M NaOH 50 C Day Day Day Day 0 1 3 6 Day 0 Day Day Day Day Day Day Day 1 3 6 0 1 3 6 Pu ulling Time points SEC, cief, Biacore, Cell Based Potency Assay, FTIR, & near-uv ECD
ph 3 ph 10 50 C
Second Derivative FTIR Spectra at ph3 0.00 Progressive Shifts in spectral features Arbitray Units (AU) -0.01-0.02-0.03-0.04 1720 Reference Standard Day 0 Day 1 Day 3 Day 6 1700 1680 1660 1640 1620 1600 Intra-Molecular β- Sheet 1637cm -1 Decreasing in intensity Shifting to lower wavenumbers Inter-Molecular β- Sheet 1621cm -1 Growing peak with time Wavenumber (cm -1 )
Tertiary Structure by Near UV CD spectra at ph3 50 Elipticity 0-50 No significant shifts in the near-uv ECD spectra Molecular -100-150 RS Day 0 Day 1 Day 3 Day 6-200 240 260 280 300 320 340 Wavelength (nm)
Analyzing FTIR Spectra Spectral Comparisons Spectral Correlation Coefficient (SCC) Most commonly used Area Overlap (AO) Create an overlap spectrum Modified Area Overlap (MAO) Square the intensity at each wavenumber Create an overlap spectrum Secondary Structure Quantification PROTA (Biotools) Factor analysis Uses crystal structure data and known FTIR spectra in a database Compiles the best fit of the unknown spectra Al-Azzam, W. JPharmSci. Comparability of protein therapeutics: Quantitative comparison of second-derivative amide I infrared spectra, Vol. 101, 2025-2033, 2012
Second Derivative FTIR Spectral Comparisons (ph 3) % Similar 100 80 60 40 20 0 Reference Standard Day 0 Day 1 Day 3 Day 6 Area Overlap Modified AO SCC Comparison Three methods to assess spectral similarity Reference standard compared to itself to establish a baseline Each trial of each day was compared to all three trials of reference standard All three comparison methods agree with progressive structural changes as a function incubation time
Secondary Structure Quantification of FTIR Spectra by PROTA (ph 3) 60 50 40 Reference Standard Day 0 Day 1 Day 3 Day 6 Progressive decrease in helix content and increase in sheet content % Co ontent 30 18 20 16 14 12 10 % Helix 10 8 6 0 Helix Sheet Bend Turn Coil Structure 4 2 0 y=53.87-1.15x r 2 =99.91 32 34 36 38 40 42 44 46 48 % Sheet
Correlating HOS with in-vitro Activity Structural changes detected by FTIR correlates well with gradual decreases in antigen binding and relative potency As % sheet increases and % helix decreases, % aggregate is % gg g increasing
Correlation Between Secondary Structure, Aggregates, and Binding by Biacore at ph 3 60 100 50 80 % Aggreg gate 40 30 % Antigen Binding 60 40 20 y=(1-0.030x)/(0.015-0.0005x) r 2 = 99.98 10 32 34 36 38 40 42 44 46 48 20 y = -2.00x+128.24 r 2 =99.68 0 10 20 30 40 50 60 % Beta Sheet % Aggregate As % beta sheet increases, the % aggregate also increases As aggregation grows there is a direct correlation with loss of binding activity
ph 3 ph 10 50 C
Second Derivative FTIR and Near-UV ECD Spectra at ph10 0.00 50 0 Arbitrary Units (A AU) -0.01-0.02 Reference Standard -0.03 Day 0 Day 1 Day 3 Day 6-0.04 1720 1700 1680 1660 1640 1620 1600 Molar Elipticity -50-100 -150 Ref Std Day 0 Day 1 Day3 Day 6-200 240 260 280 300 320 340 Wavenumber (cm -1 ) 1 Wavelength (nm) Second derivative amide I IR and near-uv ECD spectra at ph10 over 6 days show minor spectroscopic differences
Correlating HOS with in-vitro Activity (ph 10) % 140 120 100 80 Day 0 Day 1 Day 3 Day 6 No significant changes in secondary structure A slight increase in aggregation with time An increase in the Acidic peak %Acidic peak 60 40 20 An increase in binding at day 6 Possibly due to aggregation 0 AO % Aggregatee Antigen Binding Relative Potency % Acidic (cief) % Helix % Sheetet
Different Degradation Pathways CH2 CH3 CH3 CH3
ph 3 ph 10 50 C
Second Derivative FTIR Spectra, Near-UV ECD and Correlations at 50 C trary Units (AU) Arbit 0.00 120-0.01-0.02-0.03-0.04 1720 Reference Standard Day 0 Day 1 Day 3 Day 6 1700 1680 1660 1640 1620 1600 % 100 80 60 40 20 Day 0 Day 1 Day 3 Day 6 Molar Elipticity 50 0-50 -100 Wavenumber (cm -1 ) Ref Std -150 Day 0 Day 1 Day 3 Day 6-200 240 260 280 300 320 340 Wavelength (nm) 0 AO % Aggregate Antigen Binding Relative Potency % Acidic (cief) % Helix % Sheet Second derivative amide I IR and near-uv ECD spectra at 50C over 6 days show minor spectroscopic differences There are very slight trends in some of the techniques
Conclusions There is a time dependant loss in activity and shift in secondary structure when the IgG is exposed to low ph The FTIR could pick up these structural changes A slight increase in activity on day 6 as well as a time dependent increase in aggregation and acidic species was observed when the IgG was exposed to high ph There was no significant loss in activity or change in structure to the IgG when exposed to heat Correlating higher order structure attributes with in-vitro data provides insights into degradation pathways with different stresses These insights can provide useful data for formulation development as well as stability
Thank you Aston Liu Lee Olszewski BAS Joe Minetti Peter Suchecki Marisa Jones Terri Westervilt Hillary Montgomery Will Riches Yu Xue
Property of GlaxoSmithKline
Back Up Slides
Spectral Correlation Coefficient (SCC) Correlation coefficient, r, is calculated using the following equation r = N x i y i 2 2 yi x i y where x i and y i represent the spectral absorbance values of the reference and sample spectra at the ith frequency position r value of 0.0 indicates no similarity between spectra r value of 1.0 indicates that spectra are identical
Area Overlap (AO) The maximum signal between two spectra at the each wavenumber was recorded to create an overlap spectrum Wavenumber (cm -1 ) Reference standard Sample Area Overlap: 82% % AO = Area Area Reference overlap *100
Modified Area Overlap (MAO) MAO method was developed in order to enhance the sensitivity of the AO algorithm. Square the signal at each wavenumber. Modified Area Overlap (MAO) method amplifies the residual intensity near the baseline throughout the entire range. S = MAO ( S 2 2 nd. der. ) A sq S 2nd.der. : signal of the 2 nd derv. spectrum at a given wavenumber A sq : is the total area of (S 2nd Der ) 2 S MAO : the resulting signal Al-Azzam, W. JPharmSci. Comparability of protein therapeutics: Quantitative comparison of second-derivative amide I infrared spectra, Vol. 101, 2025-2033, 2012
PROTA Structure Analysis (Thermal) 40 30 Reference Standard Day 0 Day 1 Day 3 Day 6 % Co ontent 20 10 0 Helix Sheet Bend Turn Coil Structure
Spectral Comparisons (Thermal) 120 100 80 % Similar 60 40 20 0 Area Overlap Modified AO SCC Reference Standard Day 0 Day 1 Day 3 Day 6 Comparison
PROTA Structure Analysis (ph 10) 40 30 Reference Standard Day 0 Day 1 Day 3 Day 6 ent % Cont 20 10 0 Helix Sheet Bend Turn Coil Structure
Spectral Comparisons (ph 10) 100 80 % Similar 60 40 20 0 Reference Standard Day 0 Day 1 Day 3 Day 6 AO MAO SCC Comparison