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Gene therapy trial for haemophilia B UCL/StJude’s Trial Update at 4 years Edward Tuddenham Katharine Dormandy Haemophilia Centre, Royal Free Hospital.

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Presentation on theme: "Gene therapy trial for haemophilia B UCL/StJude’s Trial Update at 4 years Edward Tuddenham Katharine Dormandy Haemophilia Centre, Royal Free Hospital."— Presentation transcript:

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2 Gene therapy trial for haemophilia B UCL/StJude’s Trial Update at 4 years Edward Tuddenham Katharine Dormandy Haemophilia Centre, Royal Free Hospital and University College London UK

3 Haemophilia B gene therapy Potential for a cure through continuous, 24/7, endogenous expression of FIX protein at therapeutic levels following a single gene transfer manoeuvre Excellent model for gene therapy approaches Single gene defect (deficiency of FIX gene) Therapeutic goal modest; An increase in plasma FIX levels above 1% would be sufficient ameliorate the bleeding phenotype Efficacy can be assessed by validated routine laboratory assay Tight regulation not required Wide range of FIX levels are likely to be efficacious and non- toxic

4 Adeno-associated viral vectors for haemophilia gene therapy – Non-pathogenic single stranded DNA based parvovirus – Replicates only in the presence of helper virus – Easy to render “Gutless”  reduced risk of immune response to viral proteins – Mediate stable long term transgenic FIX expression following a single administration of the vector into liver – Episomal copies; Integration rare – Multiple serotypes with distinct tissue tropism and immunology repcap ITR Wild type AAV ITR LP1 FIX cDNA ITR pA rAAV AAV5AAV9 AAV2 AAV8 20 nm

5 Key aspects of our phase I gene therapy trial for haemophilia B 1. Vector pseudotyped with AAV8 capsid Seroprevalence of AAV8 in humans is lower than AAV2 3. Vector administered in the peripheral circulation A simple mode of vector delivery that takes advantage of the strong tropism of AAV8 for the liver, the native site for FIX synthesis LP1 co hFIX LP Self complementary vectors to improve potency using an expression cassette which contained a small liver specific promoter and codon optimised hFIX cDNA scAAV-LP1-hFIXco

6 Brief outline of the dose escalation arm Objective: Assess the safety and efficacy of a bolus peripheral vein infusion of our novel scAAV2/8-LP1- hFIXco In subjects with severe haemophilia B (<1% of normal, FIX:C) No immunosuppression at the time of vector administration Key entry criteria: – No evidence of pre-existing immunity to AAV8 – No evidence of active infection with Hepatitis B, C or HIV Vector Production: Children’s GMP, Memphis, TN, USA –Column chromatography purification process Empty: Full scAAV ratio of 10:1 3 Study sites: SJCRH, Stanford, UCL/Royal Free Hospital

7 Minimise risk Risks largely unknown as first in man study Immune damage of the liver Inhibitor formation HCC Sensitisation to AAV8 Elaborate 3 stage consent process Independent ombudsman assessment One subject recruited at a time with follow-up for 6 weeks Extensive monitoring

8 Characteristics of subjects in the initial phase of the study All patients recruited at Royal Free Hospital, UK PatientsS1S2S3S4S5S6 Dose category Low (2e11vg/kg) Intermediate (6e11vg/kg) High dose (2e12vg/kg) Age MutationMissenseNullMissense Promoter ProphylaxisX2/week X1/weekX2/weekX3/week Spontaneous bleeds/year

9 Safety assessments Vital signs LFTs (Subjects 1-4, 6)Vector shedding Plasma StoolsSemenSalivaUrine

10 Low vector dose Plasma FIX levels, Subject 1: 2x10 11 vg/kg Off prophylaxis for >48 months but no spontaneous haemorrhage FIX conc usage down by 77%

11 Low and Intermediate vector dose Summary of FIX expression Subject Vector dose (vg/kg) Steady state hFIX:C level post gene transfer (% of normal) Duration of expression (Months) Prophylaxis Reduction in conc usage 22x >39 Reduced ~X1/week 33% 36x >37 Reduced ~X1/fortnight 50% Transgene expression of <3% is not sufficient to permit discontinuation of prophylaxis in subjects with severe pre-existing arthropathy

12 Intermediate vector dose Off prophylaxis for >36 months. No spontaneous haemorrhage despite engaging in contact sports that had previously precipitated bleeding episode (soccer and cricket) FIX conc usage down by 88% Plasma FIX levels, Subject 4: 6x10 11 vg/kg

13 High vector dose Plasma FIX levels, Subject 5: 2x10 12 vg/kg Currently on X1/10 days prophylaxis 60mg 0 Pred FIX conc usage down by 40%

14 High vector dose Off prophylaxis for >36 months. Not required any FIX treatment 60mg 0 Pred Plasma FIX levels, Subject 6: 2x10 12 vg/kg FIX conc usage "I have not needed any of my normal treatment, either preventative or on-demand as a result of an injury. Previously, I used to infuse at home three times a week.... I play football, run and take part in triathlons - and previously I might have had to infuse both before I took part and possibly after as well. Not having to do that has been absolutely brilliant."

15 Second arm: Expansion of the high dose cohort Questions: – Will perturbation of liver enzymes occur in all subjects treated at the high dose level? – Will early treatment with steroids reduce the level of transaminitis and preserve stable expression of hFIX? – Should all high dose subjects receive prophylactic steroids and if so when should this be started and for how long? 4 new subjects recruited over the last 12 months

16 60mg 0 Pred Plasma FIX level: Subject 7; Plasma FIX level: Subject 7; 2x10 12 vg/kg Steroid course initiated at week 8 when ALT increased by 50% Currently off prophylaxis almost 24 months post gene transfer 22Y: Null mutation; antiAAV8 IgG = 1RU; X2/Week prophylaxis; 2 bleeds/year

17 Plasma FIX level: Subject 8; Plasma FIX level: Subject 8; 2x10 12 vg/kg No spontaneous bleeding episodes following gene transfer No transaminitis; No need for steroids Not required FIX concentrates following gene transfer 38Y: Missense mutation; antiAAV8 IgG = 6RU; on demand:1Xweek; 12 bleeds/year

18 Plasma FIX level: Subject 9; Plasma FIX level: Subject 9; 2x10 12 vg/kg No bleeding episodes over post gene transfer No transaminitis; No need for steroids Not required FIX concentrates following gene transfer 44Y: Missense mutation; antiAAV8 IgG = 6RU; on demand X1 week; 16 bleeds/year

19 Plasma FIX level: Subject 10; Plasma FIX level: Subject 10; 2x10 12 vg/kg Short course of steroid started at week 9 when ALT increased by >50% Required FIX concentrates for 3 episodes of traumatic bleeds 33Y: Null mutation; antiAAV8 IgG = 5RU; on demand X1/Week; 24 bleeds/year 60mg 0 Pred

20 Weeks after vector infusion Factor IX:C (% of normal) Alanine transaminase (IU/L) Figure 1

21 Figure 2A Figure 2B

22 Figure 3B S7 S8 S9 S10 Figure 3A: Longer immunological follow-up of the dose escalation cohort

23 Weeks after vector infusion AntiAAV IgG titre (Relative units/ml) Figure 4

24 Summary:1 In total 10 subjects received scAAV8-LP1- hFIXco Evidence of vector mediated human FIX expression in all 10 subjects treated to date – Level of transgenic FIX achieved is dose dependent with an average of 5% of normal at the high vector dose – Expression has remained remarkable stable over time with follow-up between months – 5/7 able to stop prophylaxis, with significant improvement in quality of life and reduction in frequency of bleeding episodes Net saving to the UK government from decrease in FIX usage is >£1.5M

25 Summary:2 Perturbation of liver enzymes has been observed in 4/6 subjects treated at the high dose level Not related to pre-treatment anti-AAV IgG levels Not related to HLA Not related to previous infection or treatment for HBC –?use steroids prophylactically between 7-9 weeks after gene transfer These results are encouraging and support further evaluation of the AAV approachThese results are encouraging and support further evaluation of the AAV approach

26 High purity (“fewer empties”) scAAV-LP1-hFIXco Commenced in Feb 2014 –Questions: –Will reducing the capsid protein load reduce the risk of transaminitis? –Will the reduction in empty particles improve hFIX expression? 1 st subject treated with new prep stable at 11 weeks after gene transfer with no evidence of transaminitis Our next haemophilia B gene therapy study

27 Other FIX trials in the pipe line 1.scAAV vector pseudotyped with AAV8 capsid 2.Codon optimised FIX cDNA containing a hyperactive FIX mutation ‘Padua’ 3.Study is open and 2 subject recruited at 1e11vg/kg PI: Samulski and Monahan Asklepios Bio & Baxter CHOP study: CHOP study: PI= Kathy High 1.ssAAV vector pseudotyped with AAV8 capsid 2.Strong liver specific promoter: HCR-hAAT 3.Study is open and 4 subject 1e12vg/kg 4.Involves add-back of empties Full:empty ratio 1:5 5.Transaminitis occurred in both but expression could be rescued with steroid Jichi medical school: Jichi medical school: Same approach as CHOP

28 Special acknowledgment The patients!!! – Their bravery permitted us to perform proof-of – concept first in man study without any expectation of benefit

29 Acknowledgments UCL/Royal Free Hospital: Amit Nathwani, Jenny Mcintosh, David Linch, Cecilia Rosales, Pratima Chowdary, Anne Riddell, Jun Pie, Chris Harrington, James O'Beirne St Jude Children’s Research Hospital: Andrew Davidoff, Ulrike Reiss, Cathy Ng, Junfang Zhou, Yunyu Spence, Chris Morton,, John Gray, Arthur Nienhuis Children’s GMP: John Coleman, Jim Allay, Susan Sleep Basingstoke Haemophilia Centre: Savita Rangarajan CBC (Bristol): Keith Smith, David Anstee and Paul Lloyd-Evans CHOP: Kathy High, Federico Mingozzi, Etiena Basner-Tschakarjan ALSAC


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