A multicenter, double blind, randomized, parallel group, placebo-controlled study to evaluate the hemodynamic responses to intravenous RLX030 infusion in subjects with acute heart failure.

Relaxin is a naturally occurring peptide hormone with a molecular weight of
5963 Daltons. Three human relaxin genes have been identified (H1, H2, and H3).
The protein product of the gene H2, is further described here and referred to
as RLX030. RLX030 is produced by
recombinant DNA technology in a bacterial expression system and is identical in
amino acid sequence and structure to the mature, naturally-occurring human
relaxin-2. In men, relaxin is expressed locally in the prostate and at very low
levels in circulation. Relaxin circulates in
women at low levels in the luteal phase of the menstrual cycle but is elevated
in pregnancy. It is believed to mediate many of the maternal physiological
responses to pregnancy including increases in renal function (Davison and Noble
1981), decreases in systemic vascular
resistance (Capeless and Clapp 1989), and increases in cardiac output mediated
largely by increased stroke volume (Capeless and Clapp 1989). Triggering
similar hemodynamic and adaptive changes as seen in pregnancy could potentially
be beneficial in the treatment of
patients with acute heart failure (AHF). RLX030 has been evaluated in
approximately 21 clinical trials in 7 indications over the last 20 years.

RLX030 is foreseen to be administered as a 48-hour continuous intravenous
(i.v.) infusion of 30 µg/kg/day on top of standard of care, to improve the
signs and symptoms of AHF (mainly dyspnea), and, ultimately, reduce heart
failure re-hospitalizations and cardiovascular death.
The Phase 3 trial (RELAX-AHF) with 30 µg/kg/day and placebo i.v. as a 48 hour
infusion is currently ongoing. The results of the Phase 2 Pre-RELAX-AHF (part
of RLX.CHF.003) showed the following potential benefits of RLX030 at doses of
10, 30, 100 and 250 µg/kg/day as 48-hour i.v. infusion compared to placebo in
patients with acute heart failure: rapid and sustained relief of dyspnea,
trends for greater relief from signs and symptoms of fluid overload, a lower
incidence of worsening heart failure, lower use of i.v. loop diuretics and
other vasodilator therapy and a shortened length of hospital stay. Additionally
there were outcome benefits up to Day 60, including improved cardiovascular
mortality and fewer rehospitalizations for heart failure or renal failure and
greater number of days alive and out-ofhospital (Teerlink et al 2009).

RLX030 activity is mediated through binding to its cognate receptor, RXFP1 (or
LGR7), localized in small renal and mesenteric arteries and in the thoracic
aorta in mice and rats of both sexes, as well as in human blood vessels. The
pharmacological effects of relaxin include
increased production of nitric oxide, inhibition of endothelin-1, inhibition of
angiotensin II, increased production of vascular endothelial growth factor
(VEGF), and local up-regulation of matrix metallo-proteinases (MMP). These
effects lead to arterial vasodilation, increased
arterial compliance, and may have favorable effects on renal hemodynamics.

Since RLX030 works indirectly through multiple pathways with short- and
long-term effects on hemodynamics, it may be particularly well-suited for
therapeutic treatment of heart failure,
with acute and sustained effects, as well as a favorable benefit-risk profile.
The current study is designed to provide data to support the understanding of
RLX030*s Mechanism of Action (MoA) through effects on hemodynamics in patients
with AHF at the therapeutic dose,
information about the on-set and off-set of effects and population
pharmacokinetics.

Primary objective(s)
• To assess the effects of RLX030 compared to placebo on hemodynamic variables
(PCWP, CI) during the first 8 hours administered as i.v. infusion over 20 hours
in subjects with Acute Hart Failure

Secondary objective(s)
• To assess the onset and offset of the hemodynamic effects during and
following the end of the i.v. infusion of RLX030 over 20 hours compared to
placebo when administered to subjects with Acute Hart Failure.
• To investigate the population pharmacokinetics of RLX030 during and after
i.v. infusion over 20 hours in subjects with Acute Hart Failure.
• To assess the effects of 20 hours i.v. infusion of RLX030 on diuresis and
calculated creatinine clearance when administered to subjects with Acute Hart
failure
• To assess the effects of 20 hours i.v. infusion of RLX030 on central aortic
systolic pressure (CASP), and radial arterial pulse waveform compared to
placebo in subjects with Acute Hart Failure.
• To assess the tolerability of 20 hours i.v. infusion of RLX030 compared to
placebo when administered to subjects with Acute Hart Failure

This is a multicenter, double-blind, randomized, placebo-controlled study in
subjects with AHF. The study will consist of a one to three day(s) screening
period, a baseline period, a treatment period of 20 hours infusion, a wash-out
period after stop of infusion. Discharge from hospital is possible from
approximately 44 hours after start of the study drug infusion if medically
capable of doing so per Investigator*s discretion. Study Completion evaluation
is done 30 (±3) days after start of the study drug infusion.

Subjects who meet the clinical and laboratory eligibility criteria at screening
will have a Swan-Ganz catheter inserted and the hemodynamic eligibility
criterion will be assessed. If also this criterion is met the baseline
evaluations are performed. All baseline safety evaluation
results must be available prior to dosing.

During the study the hemodynamic parameters RAP, PAP, PCWP and CO will be
measured repeatedly. At the same time points, blood pressure and CASP will be
measured. Blood samples will be taken at intervals for PK estimation and for
assessment of selected biomarkers.
Urine will be collected for assessment of diuresis, natriuresis, creatinine
clearance, and for assessment of selected biomarkers and urinary albumin
creatinine ratio (UACR).

Safety assessments will include physical examinations, ECGs, vital signs,
investigator assessments of signs and symptoms, standard clinical laboratory
evaluations (hematology, blood chemistry, urinalysis), adverse event and
serious adverse event monitoring.

The study will be conducted in two sequential parts:
• In part 1 the dose of 30 µg/kg/day, currently used in the ongoing phase 3
trial, will be compared to placebo.

• After completion and statistical evaluation of part 1 the study may,
optionally, continue with a Part 2 to investigate additional dose(s) or dose
regimen(s) of RLX030 compared to placebo using the same study design. The
dose(s) or dose regimen(s) in part 2 will be defined in an amendment and
selected based on the results obtained with 30 µg/kg/day.

Swan-Ganz Catheterization

This study will be conducted in subjects with acute heart failure requiring
hospitalization for management of AHF and central hemodynamic monitoring.
Inclusion and exclusion criteria will ensure that the appropriate subjects will
be included in this study.

Currently available treatment options in AHF consist of primarily diuretics in
almost all subjects supplemented by vasodilators or inotropic agents in
selected subsets. In patients with preserved or elevated BP, vasodilators are
recommended at an early state for AHF patients by
the European Society of Cardiology (ESC) guidelines. In this study all patients
will receive study medication on top of standard of care which must include
loop diuretics. Therefore patients will receive standard treatment of care for
this indication. RLX030 will be administered at a dose that has proven symptom
improvement in the Phase 2b study and is currently in Phase 3 of development.
However, patients might not have an additional medical benefit from
participating in the study over standard treatment of care.

Overall, RLX030 has demonstrated an acceptable safety profile and was
well-tolerated in clinical with stable congestive HF (CHF) and AHF. Risks
involved with RLX030 administration include hypotension, increase in serum
creatinine, meno-/metrorrhagia, and anemia as a result of menometrorrhagia or
hemodilution. As with any protein, there is a possibility of allergic
reactions. Antibody formation to RLX030 has occurred in 39% of subjects
receiving RLX030 only after systemic exposure via the SC route of
administration. To date, the antibodies have been associated with no apparent
adverse events. There is no evidence that the antibodies are inhibitory nor is
there evidence of any long-term sequelae. Chronic HF patients dosed i.v. with
RLX030 for 24 hr at a dose of up to 960 µg/kg/day for 24 hours in study
RLX.CHF.001 did not develop anti-RLX030 antibodies. Because of the i.v.route
and short treatment duration, antibody formation is highly unlikely.

Risks associated with invasive hemodynamic monitoring by puncture of an access
vein and insertion of a Swan-Ganz catheter may include complications such as
bleeding, and pneumothorax. Through stimulation of the myocardium atrial and
ventricular arrhythmias can occur which are generally without hemodynamic
relevance and self-limiting. Risks also include thrombosis which may be limited
by heparinization. The risk of infections will be limited by sterile
procedures. Pulmonary infarction has also been reported. The incidence of
complications arising from pulmonary artery catheters has been reported to be
between 5 and 10% in two randomized controlled studies with hematoma being most
frequent (4%) (Binanay et al 2005a; Binanay et al 2005b).

The 20 hours i.v. infusion requiring an indwelling catheter could potentially
lead to discomfort, development of hematoma or in rare cases of phlebitis.

The risk to subjects in this trial will be minimized by adherence to the
inclusion/exclusion criteria, close clinical monitoring in a hospital setting,
strict adherence to standard catheterization practice including training of
staff and provision of manuals for study procedures, stopping rules for the
individual subject and a Data Monitoring Committee (DMC) for the entire study.