Longer acting/extended Half Life Products: Laboratory Monitoring

Transcription

1 Longer acting/extended Half Life Products: Laboratory Monitoring Steve Kitchen Lead Clinical scientist Sheffield Haemophilia Centre & UK NEQAS Blood Coagulation

2 Declaration of Interests -1 Speaker/ consultancy fees Novonordisk, Pfizer, Baxter, Bayer, Biotest Grifols, Siemens, Stago, Sysmex, Werfen

3 Declaration of Interests -2 Fishing Sheffield Wednesday Cold Beer

4 Assigning potency to products Affects results in post infusion samples Labs should select an assay for post infusion monitoring which gives same results as that used for assigning potency to the product

5 Historical position FVIII and IX concentrates Potency Labelling Some regions (USA etc) FVIII and FIX potency assigned by one stage assay Some regions (EU) FVIII potency assigned by highly defined (European pharmacopeia) chromogenic assay, FIX - one stage assay Post infusion monitoring Currently clinical labs mainly use one stage assays for post infusion

6 Assay discrepancies occur for some conventional half life products (Full length recombinant, Lusher et al 1998) Chromogenic

7 One stage and Chromogenic assays post Kogenate Lusher et al patients Coatest Chromogenic 3 one stage techniques 10 min post infusion samples Chromogenic average 37% higher than average one stage Some interpatient variation

8 Assay issues? Assay differences after ReFacto infusion 2003 UK NEQAS exercise Median One stage (78) 36.0 u/dl Median Chromogenic (12) 52.5 u/dl

9 ReFacto lab standard Concentrate Reconstitute in 1 ml water Dilute to 1 IU/ml in factor VIII deficient plasma

10 2003 NEQAS exercise Post Refacto Median One stage (78) 36.0 u/dl Median One Stage (16) (Refacto standard) 49.5 u/dl Median Chromogenic (12) 52.5 u/dl

11 Long Acting FVIII and FIX Factor VIII half life extension by 1.5 to 1.7 fold from 12 ( 8-13 ) to average of around 19 hr (range hr) Clearance/half life linked to VWF clearance Factor IX extension fold

12 EMA workshop on New Products - FVIII 7 new products Fc fusion, single chain BDD, Pegylated BDD/FL (20, 40 and 60 KD) Most products one stage and Chromogenic both valid against Who (IU) but sometimes very different potency Most labelling with Chromogenic assay Chromogenic assays more robust across different kits/methods and agree with some one stage methods but not others Dodt et al 2015

13 Pegylation Hamostaseologie, 4(supp), 2012 Bax 855 rfull length Peg Advate, 20KDa PEG, IU label potency by 1stage assay (same as Advate) Abstract at ISTH 2105 field study, routine one stage and chromogenic assays can be used. No product specific std needed.

14 Chromogenic assay (Hyphen) recovered expected values APTT SP & STA PTT-A (silica) gross underestimation. Free PEG prolongs clotting times<10% expected values Synthafax, Actin, Cephascreen (ellagic acid) most suitable

15 % of target % of target N8 GP - PEG interference results in underestimation with some aptt reagents NO EFFECT SEEN IN CHROMOGENIC ASSAYS One-stage clot assay Chromogenic assay N8-GP 0.2 IU/ml N8-GP 0.6 IU/ml N8-GP 0.9IU/ml Bowyer, Kitchen et al : Poster ISTH-SSC EHF06 1 N8-GP spiked samples

16 30 one stage assays Multiple APTT reagents (8 Ellagic acid, 19 Silica). Different deficient plasma (+/- VWF) 11 chromogenic assays ( 5 methods)

17 FVIII Assay According to aptt Reagent Activator rfviiifc Sommer et al. Haemophilia 2014:20:294-30

18 Recombinant FVIII Fc fusion protein (Sommer et al 2014)

19 CSL behringrfviii single chain Abstract at ISTH 2015 Consistently underestimated by one stage assays Chromogenic closer to target Predictable undestimation Correction factor?

20 EMA workshop on New Products - FIX 4 products Full length, Fc fusion, Albumin fusion, Pegylated (40 kd) Valid assays against WHO (IU) All using One stage assay for potency labelling Different reagent sets (results differ substantially according to reagents) Dodt et al 2015

21 % Target Laboratory measurement of N9-GP N9-GP was accurately measured by the one-stage clotting assay using DG Synth and SynthAFax or the Rossix and Hyphen chromogenic FIX assays % of target One-stage clotting assay Chromogenic assay % of target Actin FS APTT SP DG Synth Pathromtin Synthafax Synthasil 25 0 Rossix Biophen NG-GP 0.2, 0.6, 0.9 IU/ml Bowyer AE, SSC Annual Meeting 2014, EHF11

22 Pegylated (40 kd) FIX N9-GP One stage assays against WHO plasma standard ( Holm et al ISTH Poster 2013) % recovery % recovery +/- 25% in white ck prest Synthasil AFSL AFS cephasc dapttin sfax act pathr trini s trini hs sp trini auto trini hs ptt auto aptt lyo

23 Pegylated FIX (N9-GP) One stage assays against N9-GP standard (Holm et al ISTH Poster 2013) % recovery 100% recovery +/- 25% in white AFS Dapttin Cephascreen AFSL Synthasil Triniclot auto SP PTT auto Trini hs sfax ck prest aptt lyo trini s act trini hs pathrompt

24 30 one stage assays Multiple APTT reagents (8 Ellagic acid, 17 Silica, 4 Kaolin, 1 Polyphenols). Different deficient plasmas and analysers Biophen Chromogenic assay (in house) Sommer et al T/H 2014

25 FIX Assay According to aptt Reagent Activator rfixfc 1-3 AFS 4-8 AFSL 9 Cephascreen Trinity Auto APTT Synthasil Stago PTT A Pathromptin Hemosil Platelin L CK Prest FIX: factor IX; aptt: activated partial thromboplastin time; rfixfc: recombinant factor IX Fc fusion protein; IU: international units BeneFIX is a registered trademark of Pfizer Sommer et al. Thromb Haemost 2014;112:

26 Chromogenic FIX (Biophen) is Suitable for Assay of rfixfc rfix product Nominal concentration (IU/ml) Mean ± SD FIX activity (IU/ml) BeneFIX ± ± ± ± rfixfc ± ± FIX: factor IX; rfixfc: recombinant factor IX Fc fusion protein; IU: international units; SD: standard deviation BeneFIX is a registered trademark of Pfizer Sommer et al. Thromb Haemost 2014;112:

27 National Hemophilia Foundation USA Medical and Scientific Advisory Council (MASAC) Laboratories routinely performing factor assays on patients with hemophilia should strongly consider addition of FVIII and IX chromogenic assays when these assays are approved by FDA (Adopted June 5 th 2014)

28 Barriers to use of Chromogenic FVIII and IX assays Perceived complexity Perceived expense

29 Which assay with no special conditions for each product? (Not all reagents have been studied) Chromogenic One stage Novo Nordisk N8 GP 40 KD peg Yes Yes/No Bayer Bay KD peg Yes Yes/No Baxalta Bax KD peg Yes Yes Biogen/Sobi rfviiifc Fc fusion Yes Yes CSL Behring rfviii Single chain? correction?correction Biogen/Sobi rfixfc Fc Fusion Yes Yes/No Novo Nordisk N9 GP 40 KD peg Yes Yes/No

30 One stage assay reagents AFS Synth asil DG Synth Pathrom ptin Syntha fax APTT Sp Cephasc reen STA PTT A Actin FSL CK Prest N8 GP Yes Yes Yes Yes Yes No Yes Bay Yes No Yes No rfviiifc Yes Yes Yes Yes Yes Yes Yes rfixfc Yes Yes Yes Yes Yes Yes No N9 GP No No Yes No No No Yes No No No

31 Long Acting Products Monitoring options Chromogenic assays ( plasma std) One stage assays with defined reagent sets One stage assays with correction factor One stage assays with product specific calibrators Global assays? No monitoring ( as for inhibitor treatments)