HARMONIZATION TEAM A6 (STABILITY) UPDATE. Yoshiaki Ohtsu 8 March 2012

Transcription

1 HARMONIZATION TEAM A6 (STABILITY) UPDATE Yoshiaki Ohtsu 8 March 2012

2 Contents 1. General update 2. Scientific discussion point 1. Stability of presence of co administered or co formulated drugs 2. Incurred sample stability 3. Transferability of stability results 4. Whole blood stability 3. Future direction

3 Contents 1. General update 2. Scientific discussion point 1. Stability of presence of co administered or co formulated drugs 2. Incurred sample stability 3. Transferability of stability results 4. Whole blood stability 3. Future direction

4 Harmonization team A6 Natasha Savoie, Canada Morten Kall, Denmark Nico van de Merbel, Netherlands Joleen White, USA Yoshiaki Ohtsu, Japan Kelly Dong, China Julie Diancin, USA Francesca Riccio, Brazil Ronald de Vries, Belgium Manish Yadav, India 4

5 Activities Building of team: May/June 2011 Start: June 2011 Definition of scope: July 2011 Summarizing stability requirements in relevant guidelines, white papers etc: August/September 2011 Evaluation of stability requirements and definition of high-, medium- and low-priority issues: October 2011 Discussion of high-priority issues and preparation of recommendations: ongoing 5

6 Scope (1/2) Spiked samples (biological and surrogate) and extracts Incurred samples and extracts Normal matrices (blood, plasma/serum, urine, tissue) Special matrices (hemolyzed, lipidemic etc) Presence of co-formulated and co-administered drugs, metabolites Stock and standard solutions, reagents Stability during sample collection and transport Stability during extraction and analysis 6

7 Scope (2/2) Definitions and nomenclature: -70 vs -80 ºC room temperature degradation vs stability vs solubility loss vs absorptive loss fresh vs stored Experimental design: t=0 vs nominal fresh vs frozen standards number of replicates concentrations and time-points ultra-low temperature for reference stability in whole blood instrument response vs concentrations Acceptance criteria: fixed or statistical approach Transferability of results between labs 7 between methods

8 Out of scope Stability of reference standards (team A4) Stability of reagents for macromolecules (team L4) 8

9 Guidelines US FDA Guidance for Industry Bioanalytical Method Validation (2001) Brazil ANVISA Guide for Validation of Analytical and Bioanalytical Methods (2003, 2011) EMA Guideline on Bioanalytical Method Validation (2011) China SFDA Guidelines on non-clinical and clinical PK studies and BA and BE studies for chemical drugs (2005) Japan PMDA, ongoing discussions 9

10 White papers Viswanathan et al. Conference Report Quantitative Bioanalytical Methods Validation and Implementation (2007) Nowatzke and Woolf. Best Practices During Bioanalytical Method Validation for the Characterization of Assay Reagents and the Evaluation of Analyte Stability (2007) Findlay et al. Validation of Immunoassays for Bioanalysis (2000) DeSilva et al. Recommendations for the Bioanalytical Method Validation of Ligand Binding Assays (2003) GCC: Recommendations on Internal Standard Criteria, Stability, ISR (2011) EBF: Blood Stability Testing (2011) 10

11 Evaluation Priority for discussion: stability issues for which there is and no guidance conflicting guidance or guidance with no or unclear scientific basis large impact on bioanalytical community 11

12 High priority Stability in presence of co-administered drugs Incurred sample stability Transferability of stability results 12 Details will be presented later in this presentation

13 Medium priority Analyte stability in whole blood no detailed guidance Details of whole blood stability will be presented later in this presentation Analyte stability in tissues no detailed guidance Analyte stability in extracted samples better distinction needed between extract stability autosampler stability re-injection reproducibility Need more discussion within GBC HT. Analyte stability in stocks and standards acceptance criteria? Comparison to nominal or t=0 13

14 Contents 1. General update 2. Scientific discussion point 1. Stability of presence of co administered or co formulated drugs 2. Incurred sample stability 3. Transferability of stability results 4. Whole blood stability 3. Future direction

15 Stability in presence of co administered or co formulated drugs (1/2) Currently, no formal guidance, but regulatory observations on several occasions Scientifically questionable, how can the presence of another drug induce instability of an otherwise stable compound? Practically, it has a relatively large impact All stability assessments? All co-administered compounds? Metabolites of co-administered compounds? 15

16 Stability in presence of co administered or co formulated drugs (2/2) GCC (Global CRO Council) survey early 2011 Results on over 100 non-proprietary and over 60 proprietary compounds were evaluated No cases seen where there was instability due to the co-administered drug Bioanalysis (2011) 3(12): GBC HT recommendation: there is no need. 16

17 Contents 1. General update 2. Scientific discussion point 1. Stability of presence of co administered or co formulated drugs 2. Incurred sample stability 3. Transferability of stability results 4. Whole blood stability 3. Future direction

18 What is ISS? ISS (1/9) Different from ISR (Incurred sample reanalysis) ISS is stability of analytes in incurred samples Scientifically, ISS may be different from spiked samples in validation studies. During discussion about ISS, aspects other than stability in incurred samples are also discussed. 18

19 Difference between ISS and spiked sample stability ISS (2/9) Unstable metabolites that degrades to the analytes (for example, acyl glucuronides) Higher enzyme activities in plasma Metabolites that compromise the specificity of the method Metabolites whose matrix effect can affect the quantification For large molecule cases, specific modification may make the difference (but this is a extremely rare case.) 19

20 ISS: guidelines ISS (3/9) Limited detail in current guidelines For compounds with potentially labile metabolites, the stability of analyte in matrix of dosed subjects should be confirmed (FDA) Study samples may be used for assessment of LTS in addition to QC samples (EMA) Ideally, study sample stability would be evaluated using freshly collected matrix from a test subject, but this approach is often impractical (Nowatzke and Woolf) 20

21 ISS: Science and practice ISS (4/9) Scientifically, it is a potentially important issue, which may influence reliability of results, when not properly controlled Practically, it has many difficult aspects, with respect to timing (difficult to perform prior to clinical phase), availability and ownership of samples, etc 21

22 ISS: when and how ISS (5/9) Evaluate metabolite data and chemical structures (no concern > no additional action required) Test stability or specificity using the metabolite standards (no concern > no additional action required) ISR failure > ISS experiments may be useful Timing flexible. Documentation should be available. Examples of experiments will be presented. 22

23 Stress test the sample preparation In time High ph, low ph Heat Protein precipitation (no heat, high or low ph) as comparison ISS (6/9) 23

24 Step 2: Check for co elution Slow chromatography ISS (7/9) (preferably UPLC), e.g minute gradient. consider doing this at two different ph Evaluate chromatograms of whole analytical run do additional peaks appear after multiple incurred sample injections? Actively search for expected problem metabolites based on in vitro / in vivo / in silico metabolism data add the MRM transitions, e.g.: +16 (N oxide) +80 (sulphate) 176 (glucuronide) 24

25 Step 3: Check stability in matrix This step can only be done when Step 1 and 2 are completed successfully Stability of analytes in matrix ISS (8/9) include but not limited to on the bench stress test storage (e.g. 4 hours and overnight) If the matrix is plasma, incurred blood stability may be tested; mix incurred plasma and blank blood at a ratio of 1:4 (v/v) 25

26 Step 4: Check ion suppression Focus on suppression of analytes or IS caused by co eluting metabolites: this step can be skipped in case of stable label IS Compare slow chromatography with validated assay (faster chromatography): if same result then probably no issue Monitor IS response: high variation is indication for suppression issues ISS (9/9) Include UV detector (LC UV MS/MS), and/or run precursor ion and Q1 scan to check for co eluting peaks 26

27 Contents 1. General update 2. Scientific discussion point 1. Stability of presence of co administered or co formulated drugs 2. Incurred sample stability 3. Transferability of stability results 4. Whole blood stability 3. Future direction

28 Transferability of stability results (1/2) Currently, no formal guidance, conflicting regulatory observations Scientifically, (in)stability is determined by physico-chemical parameters (temperature, time, matrix composition, exposure to light) Results are universally valid if storage conditions can be exactly reproduced Practically, it has a relatively large impact if stability has to be reassessed at all bioanalytical labs involved in particular long-term stability 28

29 Transferability of stability results (2/2) GBC HT recommendation: as follows. Unstable analytes needs a cautious approach. Usually, long-term stability and autosampler stability are OK to transfer because the storage condition is well-controlled. Whole blood stability is OK to transfer because actual whole blood samples are handled in animal/clinical facilities. Bench top stability will need consideration: Bracket approach can be taken (RT includes a range of temp.) Thinking globally, some bioanalytical lab may have very different RT and room temperature can vary depending on seasons. 29

30 Contents 1. General update 2. Scientific discussion point 1. Stability of presence of co administered or co formulated drugs 2. Incurred sample stability 3. Transferability of stability results 4. Whole blood stability 3. Future direction

31 Whole blood stability (1/3) Currently, no formal guidance, but regulatory observations on several occasions FDA and white paper: briefly stating the requirement to assess the stability of analytes during sample collection, handling and storage. EMA : the method must demonstrate that the concentrations obtained reflect the concentrations of the analyte in the subject at the moment of sampling. 31

32 Whole blood stability (2/3) Currently there are two approaches. Approach 1: Spike analytes in blank blood. Obtain plasma at t=0, and multiple points Measure plasma concentration The method is a validated method Approach 2: Spike analytes in blank blood. Measure blood concentration at multiple points The method is a qualified method 32

33 Whole blood stability (3/3) No single approach is available for the evaluation of whole blood stability. No single approach is available which is scientifically sound and suitable from regulatory point of view as well. Qualification or extent of qualification of whole blood method is questionable. Use of blend of two approaches is complicated, tedious and time consuming. 33

34 Contents 1. General update 2. Scientific discussion point 1. Stability of presence of co administered or co formulated drugs 2. Incurred sample stability 3. Transferability of stability results 4. Whole blood stability 3. Future direction

35 Future direction Continue discussions within team and interact with other teams Interaction with BA community, through regional organizations Preparation of science-based proposals for all items on the scope list 35