IL1-TRAP, Rilonacept, in Systemic Sclerosis

Overview of Systemic Sclerosis

Scleroderma, also known as systemic sclerosis (SSc), is a multisystem disease affecting skin
and, more variably, other tissues, commonly including joints, muscles, lungs, the
gastrointestinal tract and kidneys. It is one of a group of diseases in which fibrosis is
associated with organ dysfunction. Fibrosis can involve the liver (Lefton et al., 2009;
Pinzani et al., 2005), lung(Frankel and Schwarz, 2009), kidneys (Schnaper, 2005), and less
commonly other organs, representing a final common pathway to organ dysfunction. In SSc
tissue fibrosis is widespread, variably involving skin, lungs and the gastrointestinal tract.

Although SSc can affect almost any part of the body, skin disease is the most consistent
clinical manifestation. Skin disease typically starts in the hands with an edematous phase of
hand swelling lasting one to several months. The skin then progressively thickens and tethers
to underlying tissues. In diffuse cutaneous SSc (dcSSc), skin thickening, induration and
tethering typically extend proximally up the arm and can involve the torso, abdomen, face and
legs. Patients with limited cutaneous SSc (lcSSc) have skin disease limited to below the
elbow and face and neck as well as other characteristic clinical features. SSc skin pathology
(diffuse and limited cutaneous SSc) shows fibrosis and variable perivascular lymphocyte
infiltration in the deep reticular dermis.

SSc affects multiple other body systems. Most severe complications are seen more frequently
in dcSSc with considerable morbidity and mortality(Steen and Medsger, 2000). Lung disease
manifests as interstitial fibrosis or pulmonary arterial hypertension (PAH, more common in
lcSSc). Lung disease remains the leading cause of death among SSc patients. Gastrointestinal
disease primarily results from dysmotility. In the esophagus and stomach this most commonly
leads to esophagitis. In the small and large bowel this most commonly leads to constipation,
bowel obstruction and/or malnutrition. Renal disease is primarily manifest as accelerated
hypertension and renal insufficiency. Angiotension converting enzyme inhibitors are generally
though not uniformly effective for treating this manifestation, which previously led to
significant mortality.

Other important clinical manifestations include cold-induced vasospastic disease in
extremities (Raynaud's phenomenon) and digital ulcers. SSc can also have cardiac
manifestations. Pericarditis is the most frequent cardiac manifestation. Subclinical
pericarditis is common with large effusions developing occasionally. Myocardial involvement
with low-grade myocardial fibrosis is relatively common, but not frequently of clinical
importance (Follansbee et al., 1985). Fibrosis most commonly manifests as the appearance of a
septal infarction pattern on EKG in patients with normal coronary arteries, or as ventricular
conduction delays. Occasionally myocardial fibrosis leads to heart failure. Cardiac
arrhythmias are seen in ~5% of patients with SSc. Most common are atrial or ventricular
ectopy, generally not associated with more serious rhythm disturbances. However, thallium
perfusion defects are associated with sudden cardiac death (Steen et al., 1996).

Current treatment for SSc is limited (Steen, 2001). For most disease manifestations treatment
is primarily symptomatic and generally inadequate. The exception is renal disease,
scleroderma renal crisis, once a major cause of mortality in SSc patients, can often be
treated successfully with angiotensin converting enzyme inhibitors. Pulmonary complications
now represent the major cause of mortality. Cyclophosphamide provides some benefit in
patients with interstitial lung disease (ILD), the most lethal complication of SSc. However,
the effect of this agent on SSc-associated ILD is modest and transient (Tashkin et al., 2006;
Tashkin et al., 2007). Pulmonary arterial hypertension (PAH) also leads to considerable
mortality in SSc patients. PAH may respond to vasodilators such as epoprostanol and bosentan,
but frequently responses are incomplete and mortality still high(Badesch et al., 2009) .
Bowel hypomotility also leads to considerable morbidity and sometimes mortality. Esophageal
hypomotility is treated, frequently without success, with pro-motility and acid-blocking
agents. Dysmotility of the lower bowel and its complications are even more difficult to treat
with pro-motility agents providing modest relief in some patients and antibiotics helping in
cases of small bowel overgrowth. Thus there are limited therapeutic alternatives for SSc
patients faced with progressive lung or bowel disease.

Skin fibrosis, the hallmark feature of SSc remains without effective treatment. Although skin
changes in SSc are not a cause of mortality, they cause considerable morbidity, may reflect
similar pathological processes to those that occur in the bowel and lungs, correlate highly
with prognosis and disease progression in other organ systems, and can be reproducibly
assessed by skin score testing. Skin disease is of particular interest for evaluation in
clinical trials since it is easily biopsied and can thus be repeatedly assessed for
pathological changes during clinical trials (Lafyatis et al., 2009).

Part of the difficulty in finding effective treatments for SSc has been a continuing
uncertainty regarding what initiates pathogenesis. The cause of disease manifestations in SSc
remains obscure, although three major pathophysiologic explanations have been advanced.
Prominent pathologic changes in dermal and pulmonary tissues show fibrosis, suggesting
abnormalities in matrix deposition. Vascular disease, resulting in scleroderma renal crisis,
digital ischemia and pulmonary hypertension suggests dysfunction of the vascular endothelium.
Autoantibodies in SSc patient sera suggest that immune dysfunction and autoimmunity may
contribute to or cause disease. The different pathological features in different organs have
provided support for each of these mechanisms, but not clarified which is most important in
overall pathogenesis.

Background: IL-1 Rationale for blocking IL-1 in Systemic Sclerosis: The inflammasome and
fibrosis Several observations have implicated IL-1 in fibrotic diseases and SSc.
Environmental or occupational exposure to silica dust leads to fibrosis (Cohen et al., 2008)
and has been associated with SSc (Rustin et al., 1990). Recently, several groups have shown
in murine models that silica dust activates inflammation and fibrosis through the
inflammasome (Cassel et al., 2008; Hornung et al., 2008) . Activation of the inflammasome
also contributes to bleomycin-induced lung injury (Gasse et al., 2007).

Rilonacept blocks IL-1β signaling by acting as a soluble decoy receptor that binds IL-1β and
prevents its interaction with cell surface receptors. Rilonacept also binds IL-1α and IL-1
receptor antagonist (IL-1ra) with reduced affinity.

Rationale for Rilonacept In This Study SSc presents special problems for developing therapies
due to the heterogeneous clinical presentation, the variability of disease progression and
the difficulty quantifying the extent of disease. The variability of disease progression
presents particular challenges for deciding whom to treat, leading to overtreatment of
patients as well as misinterpretation of open label trials. This heterogeneity of disease
progression has also required recruitment of relatively large patient numbers into clinical
trials, many with skin disease that is going to stabilize or improve spontaneously (Amjadi et
al., 2009).

Purpose/Objectives

This study will utilize a 4-gene biomarker of skin disease as the primary efficacy outcome in
a short duration, placebo-controlled clinical trial of rilonacept, designed to provide
preliminary data for a larger trial. The change in 4-gene SSc biomarker skin score from day 0
to day 42 or last observation carried forward(LOCF) will be measured in both
rilanocept-treated patients as well as placebo patients and the scores will be compared.
These gene biomarkers should provide a strong surrogate for such trials in the future and, if
IL-1 is indeed the cytokine leading to fibrosis in this disease, provide a highly significant
start to finding a therapeutic for SSc that for the first time might dramatically affect
fibrosis. A central hypothesis of this study is that IL-1 inhibition will downregulate the
4-gene biomarker over a relatively short period of time, much shorter than is historically
thought necessary to see changes in the MRSS. Entry criteria will include the recent onset of
dcSSc as this is the population most likely to show progressive skin disease and also the
population examined in previous studies showing correlations between MRSS and the 4-gene
biomarker.

Secondary outcomes will include other validated measures of SSc disease activity. MRSS, SSc
health assessment questionnaire (SHAQ), which includes the health assessment questionnaire
(HAQ) and a SSc specific, patient visual analogue scale (VAS) for organ specific involvement
will be followed during the trial. Several studies suggest that the SHAQ accurately measures
disease activity and may detect smaller changes in health status. This study will also test
the effect of rilonacept on global skin gene expression using microarray analyses of skin
biopsies. In addition, serum biomarkers of SSc disease activity (COMP, THS-1 and IFI44) and a
biomarker of inflammasome activation (CRP) will be tested before and after treatment. The
change in MRSS score, SHAQ score, skin myofibroblast score, gene expression, CRP and serum
biomarkers from day 0 to day 52 will be compared between the rilanocept-treated patients and
the placebo-treated patients.

Inclusion Criteria:

- Must meet the American College of Rheumatology criteria for systemic sclerosis with
diffuse cutaneous involvement and < 24 months since the onset of the first SSc
manifestation other than Raynaud's phenomenon; or has had an increase of MRSS by 5 in
the last 6 months.

- Must have a MRSS of ≥ 15.

- Male or female patients ≥ 18 years of age.

- Able and willing to give written informed consent and comply with the requirements of
the study protocol.

Exclusion Criteria:

- Treatment with any investigational agent within 4 weeks of screening or 5 half-lives
of the investigational drug (whichever is longer).

- Ongoing use of high dose steroids (> 10mg/day prednisone or equivalent) or unstable
steroid dose in the past 4 weeks.

- Treatment with immunosuppressive (other than low dose steroids), cytotoxic or
anti-fibrotic drug within 4 weeks of screening.

- The patient has positive viral hepatitis B, hepatitis C or HIV serologies on screening
laboratories. (Patients with a positive hepatitis B surface antibody (HBsAb) test with
a history of prior hepatitis B immunization are eligible as long as other criteria are
met (i.e., negative tests for: hepatitis B surface antigen [HBsAg], hepatitis B core
antibody [HBcAb], and hepatitis C virus antibody [HCVAb]).)

- Known active bacterial, viral fungal mycobacterial, or other infection (including
tuberculosis or atypical mycobacterial disease, but excluding fungal infections of
nail beds) or any major episode of infection requiring hospitalization or treatment
with i.v. antibiotics within 4 weeks of screening.

- Patients must have a negative PPD tested within 6 months of the time of screening, or
past positive PPD treated with appropriate antibiotic prophylaxis.

- Patients with a history of malignancy within the past 5 years.

- Moderate to severe hepatic impairment, i.e., Child-Pugh Class B or C.

- Scleroderma renal crisis within 6 months or creatinine greater than 2.0

- Pregnancy (a negative pregnancy test will be performed for all women of childbearing
potential on study day 0 and 42).

- Male and female patients of child-producing potential must agree to use effective
contraception while enrolled on study and receiving the experimental drug, and for at
least 3 months after the last treatment.

- Nursing mothers

- Gastrointestinal involvement requiring total parenteral nutrition or hospitalization
within the past 3 months for pseudo-obstruction

- Moderately severe pulmonary disease with FVC < 60%, or DLCO < 50% predicted.

- Moderately severe cardiac disease with either a history of significant arrhythmia (not
to include conduction delays other than trifascicular block, or PVCs or PACs <
5/minute), clinically significant heart failure, or unstable angina.

- Hemoglobin: < 8.5 gm/dL

- White blood count < 3,000/mm3 or total neutrophil count < 1,500

- Platelets: < 100,000/mm3

- AST or ALT > 2.5 x Upper Limit of Normal.

- Total bilirubin > 1.5 x upper limit of normal (ULN). Patients with Gilbert's Disease
may be included if their total bilirubin is ≤ 3.0 mg/dL.

- Patients should not have received any live vaccine within 30 days of trial entry

- Patients with a history of rilonacept allergy will be excluded.

- Patients who, in the opinion of the Investigator, have significant medical or
psychosocial problems that warrant exclusion. Examples of significant problems
include, but are not limited to:

- Other serious non-malignancy-associated medical conditions that may be expected to
limit life expectancy or significantly increase the risk of SAEs.

- Any condition, psychiatric, substance abuse, or otherwise, that, in the opinion of the
Investigator, would preclude informed consent, consistent follow-up, or compliance
with any aspect of the study

- Current use of TNF-blockers within 4 weeks of screening