• ClinicalTrials.gov Identifier: NCT02576795¹
• A Phase 1/2, Dose-Escalation, Safety, Tolerability and Efficacy Study of Valoctocogene Roxaparvovec, 
  an Adenovirus-Associated Virus Vector-Mediated gene transfer of human FVIII in Patients with severe Haemophilia A

• Ongoing development, Active, not recruiting
• Last Update Posted: October 14, 2022¹

• Male ≥18 years of age with base FVIII level ≤ 1 IU/dL
• Treated/exposed to FVIII concentrates or cryoprecipitate for a minimum of 150 Eds

• Detectable pre-existing immunity to the AAV5 capsid^a
• Prior treatment with any vector or gene transfer agent
• Use of systemic immunosuppressive agents or live vaccines within 30 days before the viral infusion

^a Cell-based in vitro transduction-inhibition assay and total antiAAV5 antibody assay
        

AAV5/baculovirus, Spodoptera frugiperda (Sf9) insect-cell production system²

    Codon-optimized expression cassette encoding the SQ variant of B-domain–deleted human FVIII²

    HLP ³ is a 251-bp enhancer/promoter fragment consisting of:

• A 34-bp core enhancer from the human ApoE-HCR gene upstream of 
• A modified 217-bp gene promoter, which includes the distal X and the
   proximal A1B regulatory domains from SERPINA1 (α-1-antitrypsin)

The FVIII expression cassette also includes a synthetic polyA signal^{2 [supplementary material]}

    Systemic (peripheral vein infusion) ²

• Co. 1: 6e12 (1)²
• Co. 2: 2e13 (1)²
• Co. 3: 6e13 (7)^2, 4-5
• Co. 4: 4e13 (6) ^4-5

    52 weeks², 3 years⁴, 4 years⁵ and 5 years⁶

• FVIII activity levels were assessed by both OS and CH clotting assays^2, 4 
• OS FVIII activity levels were approximately 1.6⁴ to 1.65² times as high as the FVIII levels from CH 

According to Figure 1 published here⁵: 

• 20 to 24 weeks in Co. 3 (6e13 vg/kg, n=7) and
• 44 weeks in Co. 4 (4e13 vg/kg, n=6)

Early follow-up efficacy data related to ABR in Co. 1 – Co. 3 were reported here² and summarized as follows:

• Co. 1: not applicable, as the only pt. in this cohort resumed FVIII prophylaxis after W16
• Co. 2: the ABR increased from 3 to 11 events in 1/1 pts. with stable but low FVIII activity level (1 to 3 IU/dL) through W54
• Co. 3: the median ABR dropped from 16 events per year before the study to 1event per year after gene transfer (mean reduction in rate, from 16 to 2 events)

Multiyear follow-up of ABRs after treatment were reported here^{4, 5, 6} and summarized as follows:

Early follow-up efficacy data related to AIR in Co. 1 – Co. 2 were reported here² and summarized as follows:

Multiyear follow-up efficacy data of AIRs in Co. 3 – Co. 4 after treatment were reported here^{4, 6} and summarized as follows:

In Co. 3 (6e13 vg/kg), 3/7 (42.9%) pts. and in Co. 4, 4/6 pts. (66.7%) were affected by IRRs⁶

^a Percentages were calculated using the total number of pts. (N) in each analysis population as the denominator. Pts. with more than one AE of the same category were counted only once for that category
^b A Grade 1 AE of ALT increase (1.4 × ULN) occurred on study day 1389. The AE was deemed not related to the study drug by the investigator and resolved by the next study visit on day 1431 without treatment.
^c A Grade 1 AE of ALT increase (1.3 × ULN) occurred on study day 1626. The AE was deemed not related to the study drug by the investigator and resolved by study day 1631. d A Grade 1 AE of ALT increase (2.1 × ULN)
  occurred on study day 1100. The AE was deemed not related to the study drug by the investigator and resolved by the next study visit on day 1135 without treatment.
^e A Grade 1 AE of AST increase (1.7 × ULN) occurred on study day 1100. The AE was deemed not related to the study drug by the investigator and resolved by the next study visit on day 1135 without treatment

Further statements related to AEs and SAEs were reported here^{4, 6} and summarized as follows:

• Most common AEs associated with valoctocogene roxaparvovec were transient, asymptomatic, and mild-to-moderate ALT elevations
• Treatment related SAE of grade 2 pyrexia developed along with myalgia and headache in 1/1 pt. (P13, Co. 4) within 24 hours after the administration of AAV5-hFVIII-SQ
  - Symptoms resolved within 48 hours after the participant received Acetaminophen

Not reported 

8/9 pts. (59-128 U/L, 4-52 weeks)² and 11/15 pts. (peak and timing not reported)⁵

3/9 pts. (peak levels and timing not reported)² and 10/15 pts. (peak levels and timing not reported)⁴ 

Data regarding capsid directed T cell activation were reported by different publications as follows:

• 0/9 pts. (peak and timing not reported)² and Sporadic, transient positives in some pts.⁴ 
• All 15 pts. were tested negative for the AAV5-specific IFN-g responses at baseline⁷
• 4 /15 pts. were tested positive (R50 SFU/106 PBMCs) for AAV5-specific IFN-g responses at a single time point ^a post-administration and negative at all subsequent time points tested (Figure 4A) ⁷

^a PBMC samples were collected at baseline and at several time points after administration that varied by cohort but were generally every 2–4 weeks during the first 6 months, 4–8 weeks through the rest of year 1, and every 3 months thereafter

•  Yes, all pts. with elevated ALT levels were steroid responsive (mean duration of steroid treatment was 21 weeks in 7/9 pts.)²
•  Co. 3: Steroid treatment in 2/3 participants did not inhibit ALT elevations (duration not reported)⁴

• The increase in ALT levels led to decline in the FVIII activity in 1/9 (11 %) pts. in Co. 3²
  • The level in this pt. declined from 227 IU/dL to 52 IU/dL in conjunction with an increase in the ALT level from W28 to W35. 
  • The FVIII activity level subsequently increased, and no bleeding was reported
• The elevations in the ALT level appeared to have been temporally associated with decreases in FVIII expression in 4/9 pts. (P4, 5, 7, and 8) in the high dose cohort, Co. 3⁴ 

 Follow-up data regarding a diagnosed cancer in a pt. were taken from here⁸ and summarized as follows: 

• One SAE in a pt. was diagnosed as salivary gland cancer
• The cancerous mass was removed, and the pt. was monitored
• The study investigator considered the SAE as being unrelated to the treatment
   
• BioMarin announced the findings from genomic analysis from a tissue sample containing the mass, stating that: “The results  showed a comparable pattern of integration between healthy and tumor containing tissues, with no evidence emerging that vector integration contributed to the salivary gland mass.”

1. Gene Therapy Study in Severe Haemophilia A Patients (270-201). Available at: Study Details | Gene Therapy Study in Severe Haemophilia A Patients (270-201) | ClinicalTrials.gov
2. Rangarajan, S., et al., AAV5-Factor VIII Gene Transfer in Severe Haemophilia A. N Engl J Med, 2017. 377(26): p. 2519-2530. AAV5–Factor VIII Gene Transfer in Severe Hemophilia A | NEJM
3. McIntosh, J., et al., Therapeutic levels of FVIII following a single peripheral vein administration of rAAV vector encoding a novel human factor VIII variant. Blood, 2013. 121(17): p. 3335-44. Therapeutic levels of FVIII following a single peripheral vein administration of rAAV vector encoding a novel human factor VIII variant | Blood | American Society of Hematology (ashpublications.org)
4. Pasi, K.J., et al., Multiyear Follow-up of AAV5-hFVIII-SQ Gene Therapy for Haemophilia A. New England Journal of Medicine, 2020. 382(1): p. 29-40. Multiyear Follow-up of AAV5-hFVIII-SQ Gene Therapy for Hemophilia A | NEJM
5. Pasi, K., et al., Hemostatic Response is Maintained for up to 5 Years Following Treatment with Valoctocogene Roxaparvovec, an AAV5-hFVIII-SQ Gene Therapy for Severe Hemophilia A [abstract]. ISTH 2021 Congress, 2021. Hemostatic Response is Maintained for up to 5 Years Following Treatment with Valoctocogene Roxaparvovec, an AAV5-hFVIII-SQ Gene Therapy for Severe Hemophilia A - ISTH Congress Abstracts
6. Pasi, K.J., et al., Persistence of haemostatic response following gene therapy with valoctocogene roxaparvovec in severe haemophilia A. Haemophilia, 2021. 27(6): p. 947-956. Persistence of haemostatic response following gene therapy with valoctocogene roxaparvovec in severe haemophilia A - PMC (nih.gov)
7. Long, B.R., et al., Early Phase Clinical Immunogenicity of Valoctocogene Roxaparvovec, an AAV5-Mediated Gene Therapy for Hemophilia A. Mol Ther, 2021. 29(2): p. 597-610. Early Phase Clinical Immunogenicity of Valoctocogene Roxaparvovec, an AAV5-Mediated Gene Therapy for Hemophilia A - PMC (nih.gov)
8. BioMarin follows up on previously-reported serious adverse event in its phase I/II gene therapy clinical trial for haemophilia A. 2022, WFH World Federation of Hemophilia. BioMarin follows up on previously-reported serious adverse event in its phase I/II gene therapy clinical trial for haemophilia A – WFH - World Federation of Hemophilia

AAV, Adeno-associated virus; ABR, Annualized bleeding rate; AEs: adverse events; AIR, Annualized FVIII/FIX infusion rate; ALT, alanine aminotransferase; AST, aspartate aminotransferase; CH, Chromogenic Assay; Co., cohort; DOACs, Direct oral anticoagulants; D, days; EDs, exposure days; FIX, factor IX; FIX-Padua, gain of function FIX variant; FVIII, factor VIII; gc, genome copies; HEK cells, human embryonic kidney cells; IQR, interquartile range; IRR, Infusion-related reaction; NAbs, neutralizing antibodies; OS, One-stage clotting assay; Pop., population; pt., patient/participant; pts., patients/participants; P1, Participant 1; PI, phase I; PBGD, porphobilinogen deaminase; PBMC, peripheral blood mononuclear cells; SAEs, serious adverse events; SFU, spot-forming units; TAC, tacrolimus; ULN, upper limit of normal; VCN, vector copy number; vg, vector genomes; W, weeks; WT, wild type; Y, year