Safety, Tolerability, and Clinical Outcomes after

Intraarticular Injection of a Recombinant

Adeno-associated Vector Containing a TNF Antagonist Gene: Results of a

Phase 1/2 Study

The Journal of Rheumatology 2010; 37:4; Mease etal

Introduction

• Gene Tranfer through Vector• Recombinant Adeno Associated

Virus• Concept of Local TNF Antagonism• http://www.maxanim.com/genetics/c

DNA/cDNA.htm

Viral Vectors

Adeno Associated Virus Vector

• Small virus which infects humans and some other primate species

• AAV is not currently known to cause disease and consequently the virus causes a very mild immune response

• AAV can infect both dividing and non-dividing cells and may incorporate its genome into that of the host cell

• These features make AAV a very attractive candidate for creating viral vectors for gene therapy

Adv Biochem Eng Biotechnol. 2005;99:119-45

Past: Phase 1 Study

• Safety and tolerability of rAAV2-TNFR:Fc at doses up to 1 × 1011 DRP/ml

• 15 patients with inflammatory arthritis not receiving systemic TNF antagonist

Current study: Phase 1&2 study

• Repeat injections of higher doses in subjects being treated with or without systemic TNF antagonism

• 1 × 1011 DRP/ml, 1 × 1012 DRP/ml, 1 × 1013 DRP/ml

• Assess safety and tolerability• Clinical efficacy• 21 rheumatology practices in US

Materials and Methods

• Entry criteria >18yrs Diagnosis of RA, PsA & AS Persistent peripheral arthritis at least 1

joint Moderate (grade 2)/Severe (grade 3) Failure or inadequate response to 1

DMARD or biologic Have to continue same regimen through

the trial

Study Design

• Two phases • Phase 1 dose escalation enrolment• Phase 2 expansion simultaneous enrolment• Two injections administered to each patient • First injection , Double Blind, Placebo

controlled • Randomized in 3:1 • Second injection • open label , same dose, on or after 12-30

weeks of first injection

Study population

• 6 cohorts of 20 patients• Divided equally Phase 1 and 2• Phase 1: 3 cohorts for escalating

doses• Phase 2: 3 cohorts for simultaneous,

3 concentrations

Study Agent and Volume

• rAAV2-TNFR:FC• Recombinant adeno associated virus,

genotype 2• Genetically engineered complementary

DNA of fusion gene of etanercept• Extracellular domain TNF receptor

combined with Fc portion of immunoglobulin IgG1

• Knee 5ml, ankle 2ml, elbow 1.5,wrist 1ml, MCP 0.5ml

• Placebo: isotonic buffered solution

Study Procedure

• First injection: Evaluation prior to injection and post injection at or until second injections on 0.5 , 1 , 4 , 8, 12 , 18, 24 , 30 weeks

• Second injection: same as for first• Criteria of second injection: degree

of swelling similar or worse then at baseline on or after 12 weeks until 30 week

Study Procedure

o Gene Transfer or Biodistributiono Monitoring of Fusion genome or DNA in

blood, synovial fluid and local and systemic tissue

o Monitoring of TNF fusion protein in serum, synovial fluid

o Monitoring of TNF antagonism or TNF binding activity

o Immune response to AAV2 capsido Clinical outcome, local and systemic effects

Gene and Protein analysis

• Gene Transfer : PCR for fusion DNA Subjects with 1 × 1012 DRP/ml, 1 × 1013 DRP/ml Blood: Pre and post 1 , 4 , 8 , 12 weeks Synovial: Pre and post 4, 12 weeks , also

unscheduled

Protein Expression : quantitative radioimmunoassay Standardized drug curves for patients on

etanercept, adalimumab and infliximab Pt not on antiTNF, lower limit of detection

was 0.012ug/ml

Immune response

• Humoral immune response: neutralizing antibody titer (NT) against AAV2 prior & 4 , 12 , 24 , 30 week

• Cellular immune response: ELISASPOT assay detects IFN-g release and number of T cells stimulated by synthetic AAV2 peptide

Clinical Outcome

Local Joint assessment• Tenderness and swelling ; Grade 0-3• Parameters for clinically relevant

response based on VAS >30% global improvement in target

joint >30% improvement in function Proportion of patients with 2 point

decrease in pain

Patient Based Outcomes

• Patient Based evaluation in phase 2: • VAS 10cm: Global symptoms,

function, satisfaction with response to study drug

• Functional Assessment of target joint

• Disability of arm, shoulder and hand scale• Modification of RA outcome score

Clinical Outcome

• Systemic Efficacy Measures– Tender and swollen joint counts– Patient VAS pain score– Physician global VAS– Patient global VAS– ESR, CRP– HAQ, BASDAi, ACR 20, DAS scores

Results

o Enrolmento Safety and Protocol amendmento Adverse effectso Clinical Efficacyo Local Gene Transfero Protein Expressiono Immune response to AAV2 capsid

Enrolment and Disposition

• 147 screened, 127 subjects selected and randomized

• 61 in Phase 1 dose escalation: 3 cohorts

• 62 in phase 2 expansion: 3 cohorts• Randomized equally and 1:3 ration for

study drug versus placebo• July 2007, 74/127 had received

second injection

Safety and Protocol amendment

- Hold on study • A case of disseminated histoplasmosis after

18 weeks of open label second injection • Dose of 5 × 1012 DRP/ml ( NOT 1 × 1012

DRP/ml) in 36 years female with RA on concomitant adalimumab therapy

NEJM publishes investigation of the death

Liver-biopsy -areas of necrosis, with mild inflammatory infiltrate; histoplasma organisms (arrows) can be seen (Panel B, Gomori methenamine silver stain)

A specimen of the right kidney has random foci of necrosis containing histoplasma organisms (arrows) (Panel C, Gomori methenamine silver stain)

Retroperitoneal hematoma

Delay in the study

• Study resumed after protocol amended for rescreening prior to second injection for safety monitoring (details on clear)

• SAE was thought to be unrelated to study

• 21/37 received 2nd injection after 2-7month delay

• 12 withdrew consent

Adverse effects• More in Study group but same for 1st and

2nd injection• 20% higher local site reaction occurring

with in 2 weeks of injection correlated with increased dose

• Local reactions were unrelated to systemic TNF use but linked to higher NT titers

• 3 given systemic steroids• 6 -Serious Infections: (3,2,1 in each dose

group respectively)• 3/6 were on systemic anti TNF therapy

Clinical EfficacyPhase 1 versus Phase 2 @ 12

weeks Clinically relevant decrease in swelling

noticed only in phase 1 study group arm• Phase 1 had 13%-27% compared to none

in placebo• Phase 2 had 12-19% in treatment group

and 19% in placebo

Clinically relevant decrease in tenderness• No difference in either arm of both phases

Phase 1: 12 weeks post 1st injection

Physical Examination

Phase 2 : 12 weeks post 1st injection

Physical Examination

Clinical Outcome after 1st injBoth Phases

Phase 2 patient reported outcomes

12 week of 1st injection• Pertaining to Target Joint• >30% improvement in target joint

global VAS : 42% versus 19% (p=0.14)• >30% improvement in target joint

function VAS : 32% versus 19% (p=0.36)

• 2 point decrease in joint pain : 12% versus 6% (p=0.67)

Phase 2 12 week patient reported

outcomes

Systemic outcomes12 weeks after 1st injection

• Modest improvement in systemic measures of inflammatory arthritis in both phases

• All treatment group irrespective of the dose and systemic anti TNF therapy had modest improvement in their

Systemic outcomes12 weeks after 1st injection

Clinical outcomes after 2nd inj

Immune response to AAV2 Capsid

Local gene transfer and expression

Serious Adverse effects

Adverse Events

Discussion

• Pros– New concept of treatment– Large number of patients– Attempt to address efficacy– Alternative to systemic therapy– No proven systemic TNF antagonism– Less although immunogenic

Discussion

• Cons– Expensive– Single stranded DNA– Mild clinical efficacy– Local tissue invasion– Local reactions