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Dr. Harish L. Rao ☆ India, 2007-08-30 10:55 (6522 d 12:32 ago) (edited on 2007-08-30 16:02) Posting: # 1039 Views: 8,921 |
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Dear Group Members, Let's first assume that we are not performing any outlier test. During Bioanalytical Method Validation, do we need to include the failed QCs in the Inter & Intra batch summary tables for Global Mean & CV% calculations? Thanks & regards, DR. HARISH L. RAO |
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Helmut ★★★   Vienna, Austria, 2007-08-30 14:05 (6522 d 09:22 ago) @ Dr. Harish L. Rao Posting: # 1041 Views: 7,364 |
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Dear Harish! ❝ Let's first assume that we are not performing any outlier test. Good idea - would be possible for n>6 anyway, which in validation generally is performed only for LLOQ-samples. ❝ During Bioanalytical Method Validation, do we need to include the failed ❝ QCs in the Inter & Intra batch summary table for Mean & CV% ❝ calculations? Yes, you should include all measured values in the report (your method's specifications should be transparent). Excluded values should be flagged (i.e., by means of an asterisk leading to a footnote, or I would suggest to present two tables for Accuracy/Precision; one with and the other one without excluded values - making the life of auditors and regulatory inspectors less miserable. See also this thread. P.S. I changed your user name from capitals only to mixed-case. — Dif-tor heh smusma 🖖🏼 Довге життя Україна! ![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png) Helmut Schütz ![[image]](https://static.bebac.at/img/CC by.png) The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes |
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Ohlbe ★★★ France, 2007-08-31 12:46 (6521 d 10:41 ago) @ Helmut Posting: # 1042 Views: 7,208 |
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Dear Harish, Also have a look at the report of the "Crystal City III" FDA/AAPS workshop, page E36, under "Analytical/validation reports should include", point 2. QC data from validation runs that only failed to meet QC acceptance criteria with no assignable cause for failure should be included in the precision and accuracy estimation. If you have to include data from failing runs, excluding some results from validated runs is really not an option... Or at least have two versions of the tables in the validation report, one with and one without the failing results, as suggested. Regards Ohlbe |
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Charl ● 2007-09-02 17:11 (6519 d 06:16 ago) @ Ohlbe Posting: # 1050 Views: 7,189 |
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dear ohlbe.... refering to your answer by the "crystal city III". I read the paper previously and just revised it, I have some points that I like to discuss. 1- Page E33 CALIBRATION CURVE AND QC RANGES " it is not necessary to reanalyze samples analyzed before optimizing the standard curve or QC concentrations." does that means that if I evaluated the first set of 6 batches on a linearity range narrower than it should be data will still accepted? 2- page E34 INCURRED SAMPLE RE-ANALYSIS "the study sample results obtained for establishing incurred sample reportducibility may be used for comparison purposes, and do not necessarily have to be used in calculating reported sample concentration." what does it mean???? 3- page E 36 Source data documentation "Modification of calibration response (deletion of individual standard points that exceed predefined acceptance limits or alteration of the standard curve range" can I conclude that in my final study report I can delete some unaccepted points from my linearity range, and report it as (blank), ? what MODIFICATION means to u?? 4- page E 37 STABILITY RECOMENDATIONS "...intended (nominal) concentrations should be used..." Why we dont report stability in absolute peak area, thus reporting in concentrations and comparing with nominal values will depend also on the sensitivity of the method and the interferance of slope variation will account then... 5- page E38 MATRIX EFFECTS FOR MS-BASED ASSAYS "presence of matrix ions and absence of matrix ions" does this means to u that comparision is done between spiked plasma samples and spiked mobile phase samples?? regards charl |
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Ohlbe ★★★ France, 2007-09-03 01:50 (6518 d 21:37 ago) @ Charl Posting: # 1051 Views: 7,189 |
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Dear Charl, ❝ " it is not necessary to reanalyze samples analyzed before optimizing the standard curve or QC concentrations." ❝ ❝ does that means that if I evaluated the first set of 6 batches on a linearity range narrower than it should be data will still accepted? The discussions initiated by the FDA at Crystal City were regarding situations they met where the study was initiated with a range that proved during the study to be too wide. With a MQC at mid-range and a HQC in the upper range of concentrations you may then end-up with only one QC (LQC) in the range of concentrations measured during the study. Or the opposite: LLOQ very low compared to measured concentrations, then LQC and possibly MQC below most concentrations. FDA's recommendation was to use the correct range right from the start  and part of the audience had to remind them that the guideline applies not only to BE trials (where you may indeed know what concentrations you can expect), but also to pre-clinical and early human development, where you have no idea. The final recommendation was to adapt the range after the first few runs, but not to repeat the analysis of these first runs. Your hypothesis (range too narrow during the first runs) was not discussed. IMHO: data from the first runs that are within the calibration range remain acceptable; samples outside this range are to be reassayed after dilution (if too high) or after widening the range; widening the range requires additional validation of your method.❝ 2- page E34 INCURRED SAMPLE RE-ANALYSIS ❝ "the study sample results obtained for establishing incurred sample reportducibility may be used for comparison purposes, and do not necessarily have to be used in calculating reported sample concentration." ❝ ❝ what does it mean???? The FDA wants you to demonstrate the precision of your method using real-life samples, not only spiked samples. Meaning that if you want to comply with this requirement you will have to re-assay some of the samples from your study. The idea is to use the results of the first determination for your PK analysis, and have a table somewhere listing the results of whatever you will have done to demonstrate precision on incurred samples. You do not need to treat these results as per your procedure on repeat analysis to select which result should be reported. ❝ 3- page E 36 Source data documentation ❝ "Modification of calibration response (deletion of individual standard points that exceed predefined acceptance limits or alteration of the standard curve range" ❝ can I conclude that in my final study report I can delete some unaccepted points from my linearity range, and report it as (blank), ? what MODIFICATION means to u?? As per the FDA guideline you can delete a standard from your calibration curve if the back-calculated concentration deviates from the nominal concentration from more than 15 % (20 % for LLOQ). The usual process is not to report it as (blank) but to report the back-calculated concentration, with an asterisk or any mark leading to a note identifying it as excluded. Also don't forget the end of the sentence: Modification of calibration response [...] should be documented with sufficient detail to demonstrate that the changes were justified and/or followed established procedures. Remember that the 15% / 20 % is to be calculated before the standard is excluded, not after ! Exclusion of a standard will change the calibration curve parameters and the % deviation of a standard will be modified (increased) after its exclusion. ❝ 4- page E 37 STABILITY RECOMENDATIONS ❝ "...intended (nominal) concentrations should be used..." ❝ ❝ Why we dont report stability in absolute peak area, thus reporting in concentrations and comparing with nominal values will depend also on the sensitivity of the method and the interferance of slope variation will account then... It depends what stability experiment you are considering... For stock solution stability, or on-injector stability, the use of peak area may be of interest. But for long-term stability of plasma samples ? If you're not using the internal standard you will run into trouble. ❝ 5- page E38 MATRIX EFFECTS FOR MS-BASED ASSAYS ❝ "presence of matrix ions and absence of matrix ions" ❝ does this means to u that comparision is done between spiked plasma samples and spiked mobile phase samples?? I can't remember matrix effect studies being discussed in detail during the meeting. There are much better and more detailed papers available on this topic... Regards Ohlbe |
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Charl ● 2007-09-03 12:13 (6518 d 11:14 ago) @ Ohlbe Posting: # 1053 Views: 7,160 |
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dear ohlbe I value your feed back notes  ❝ The FDA wants you to demonstrate the precision of your method using real-life samples, not only spiked samples. Meaning that if you want to comply with this requirement you will have to re-assay some of the samples from your study. The idea is to use the results of the first determination for your PK analysis, and have a table somewhere listing the results of whatever you will have done to demonstrate precision on incurred samples. ❝ You do not need to treat these results as per your procedure on repeat analysis to select which result should be reported. what is the minimum re-analysis points is accepted to demonstrate reproducibility from the whole incurred samples? re-analysis done in duplicate are enough? what if my plasma sample volumes does not allow me to do re-analysis for more than twice?  Regards Charl |
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Ohlbe ★★★ France, 2007-09-03 12:20 (6518 d 11:07 ago) (edited on 2007-09-03 18:21) @ Charl Posting: # 1054 Views: 7,073 |
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Dear Charl, ❝ what is the minimum re-analysis points is accepted to demonstrate reproducibility from the whole incurred samples? That's a question FDA refused to answer, leaving it to your best scientific jugement... They didn't say exactly what they want, how they want it to be presented and how they will interpret it Regards Ohlbe |
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Helmut ★★★ Vienna, Austria, 2007-09-03 21:49 (6518 d 01:38 ago) @ Ohlbe Posting: # 1055 Views: 7,133 |
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Dear Charl & Ohlbe, ❝ ❝ what is the minimum re-analysis points is accepted to demonstrate reproducibility from the whole incurred samples? ❝ That's a question FDA refused to answer, leaving it to your best scientific jugement... They didn't say exactly what they want, how they want it to be presented and how they will interpret it Wonderful. The entire Section sounds like some kind of Voodoo to me; I’m not getting the point(s).  ‘It is generally accepted that the chance of incurred sample variability is greater in humans than in animals, …’ Why the h... do they claim that the ’chance of incurred sample variability is greater in humans than in animals’?  I don’t think that this is 1. ‘generally accepted’, and The most disturbing fact is the open system like: ‘The final decision as to the extent and nature of the incurred sample testing is left to the analytical investigator, and should be based on an in-depth understanding of the method, the behavior of the drug, metabolites, and any concomitant medications in the matrices of interest…’ Even if ‘based on an in-depth understanding’ anything we plan will be entirely exploratory. We cannot set any specifications, because before having analysed our biosamples, we simply don’t know anything about the outcome. This may be acceptable for First-In-Man studies (which are exploratory in nature anyway), but will be considered poor taste in any pivotal trial. ‘It is recognized that accuracy of the result generated from incurred samples can be more difficult to assess.’ IMHO it’s not possible at all, as far as only re-analyis is considered. Or should we arbitrarily set the first result to 100% and report ±x% for the second result? The ‘true’ concentration of an unknown sample is (by definition) always unknown. We assign a concentration to a sample, nothing more. Therefore talking about accuracy is simply nonsense (unless we start dealing with standard additions). ‘First-in-human, proof-of-concept in patients, special population, and bioequivalence studies are examples of studies that should be considered for incurred-sample concentration verification.’ Here we are. FIM – OK, POC – why not, but BE?! Everybody is measuring subject's test/reference samples in a cross-over manner in the same analytical batch – so what? Even if day-to-day precision of incurred samples is lousy, it does not influence the assessment of BE (maybe FDA’s agents should have sneaked across their border). — Dif-tor heh smusma 🖖🏼 Довге життя Україна! Helmut Schütz The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes |
Ing. Helmut Schütz