A phase 1 double blind, placebo controlled study of ALX-0141 single dose subcutaneous administration in healthy post-menopausal women

The drug to be given, ALX-0141, is a new, investigational compound that may
eventually be used for the treatment of bone loss.
The skeletal system is constantly remodeling in response to hormonal and
gravitational signals from the environment. This continuous remodeling consists
of two linked processes: bone resorption (loss of bone substance) and bone
formation. Both processes are in balance in a healthy body. ALX-0141 is
expected to help restore balance between bone resorption and bone formation in
certain diseases like osteoporosis or rheumatoid arthritis. ALX-0141 is a
so-called nanobody which means that it is a very small simple protein that is a
fraction of an antibody binding to receptors on cells that are involved with
bone resorption and bone formation. Some of the advantages of these fragmented
antibodies in comparison to normal antibodies (monoclonal antibodies) are that
they are produced more easily and they are less likely to cause any allergic
reactions.

- to determine the maximum tolerated dose (MTD) and/or biological effective
dose (BED) after single s.c. administration of ALX-0141
- to determine the safety and tolerability of escalating single doses of
ALX-0141 in healthy postmenopausal women

Design:
A double-blind, placebo controlled, single-ascending dose study in 1 cohort of
2 healthy postmenopausal female subjects receiving a single subcutaneous (s.c.)
dose of ALX-0141 or placebo (1 verum and 1 placebo) and 5 cohorts of 8 healthy
postmenopausal female subjects receiving a single s.c. dose of ALX-0141 or
placebo (6 verum and 2 placebo).

Procedures and assessments
Screening and each follow-up visit:
Clinical laboratory (including Ca and intact-parathyroid hormone (PTH)), 25
hydroxy vitamin D in serum, immunophenotyping of white blood cells (WBC) vital
signs, physical examination (at screening and first follow-up visit only),
weight, 12-lead ECG (in triplicate at screening), immunogenicity,
pharmacokinetics (PK), pharmacodynamics (PD);
At eligibility screening: medical history, height, mammogram#, drug and alcohol
screen, HBsAg, anti HCV and anti HIV 1/2; clinical laboratory (including Ca and
intact-PTH), 25 hydroxy vitamin D, immunophenotyping of WBC, weight, drug and
alcohol screen, vital signs and ECG to be repeated upon admission

Observation period:
One period in clinic from -65 h (Day -3) before up to 144 h after drug
administration on Day 1 and ambulatory visits on Day 14±2, 30±2, 60±5 and 90±5
(follow-up) and additional follow-up visits if necessary*.

Blood sampling:
For PK of ALX-0141 in plasma: pre-dose and 8 h and 12 h post-dose, once in the
morning on Days 2-7 and once on Days 14±2, 30±2, 60±5 and 90±5 (follow-up) and
additional follow-up visits if necessary*.
For PD of procollagen type I amino-terminal propeptide (P1NP), cross-linking
telopeptide of type 1 collagen (CTX-1), bone specific alkaline phosphatase
(BAP) and tartrate resistant acid phosphatase (TRACP5b) in serum: at screening,
once in the mornings on Days -2, -1, pre dose and 8 h and 12 h post-dose on Day
1, and once in the morning on Days 2, 3, 4, 5, 6, 7, 14±2, 30±2, 60±5 and 90±5
(follow-up) and additional follow-up visits if necessary*. Samples should be
taken at the same timepoints.
For immunogenicity (anti-drug antibodies in plasma): once on Days -2, -1, 1
(pre-dose), 7, 14±2, 30±2, 60±5 and 90±5 (follow-up) and additional follow-up
visits if necessary*.
For additional study related research on immunogenicity: once on Day -2 and Day
60±5.

Urine sampling:
For PD of CTX-1& and N-terminal telopeptide of type 1 collagen (NTX-1),
creatinin (under fasted conditions) in urine: at screening, once on Days 2,
-1, 1 (pre-dose), 2, 3, 4, 5, 6, 7, 14±2, 30±2, 60±5 and 90±5 (follow-up) and
additional follow-up visits if necessary*.

Safety assessments:
Adverse events (AEs) and local tolerability: throughout the study; vital signs
and 12-lead electrocardiogram (ECG): pre-dose (ECG in triplicate) and 3, 6, and
9 h post-dose on Day 1, once in the morning on Days 2-7 and once on Days 14±2,
30±2, 60±5 and 90±5 (follow-up) and additional follow-up visits if necessary*;
clinical laboratory (including Ca and intact-PTH), 25-hydroxy vitamin D,
immunophenotyping of WBC to differentiate between B and T lymphocytes: once on
Days 1, 2, 4, 6, 14±2, 30±2, 60±5 and 90±5 (follow-up) and additional follow-up
visits if necessary*; immunogenicity at pre-dose Day 1, Days 7, 14±2, 30±2,
60±5 and 90±5 (follow-up) and additional follow-up visits if necessary*.

Bioanalysis:
Analysis of plasma ALX-0141 samples using a validated method by PRA.
Analysis of serum P1NP, CTX-1, BAP and TRACP5b samples using validated methods
by PRA.
Analysis of urine creatinin, NTX-1, CTX-1 (optional&) samples using validated
methods by PRA.
Analysis of anti-drug antibodies (ADA) samples using validated methods by PRA.
Analysis of 25-hydroxy vitamin D using a validated method by PRA.
Immunophenotyping of WBC using validated methods by PRA.
Analysis of immunogenicity using validated methods by Ablynx NV.

# only applicable if no mammogram was conducted within 9 months prior to the
study
* a monthly additional follow-up visit will be conducted if CTX-1 levels are
not back to baseline - 30% at Day 90 and will be repeated until CTX-1 levels
are back to baseline - 30%
& CTX-1 urine samples will be frozen and analyzed upon request of the Sponsor

Study Medication:
Active substance : ALX-0141
Activity : anti-RANKL
Indication : bone loss
Strength : 65 mg/mL
Dosage form : s.c. injection

Treatments :
Cohort 1: a single s.c. dose of 0.003 mg/kg of ALX-0141 (n=1) or placebo (n=1)
on Day 1
Cohort 2: a single s.c. dose of 0.01 mg/kg of ALX-0141 (n=6) or placebo (n=2)
on Day 1
Cohort 3: a single s.c. dose of 0.03 mg/kg of ALX-0141 (n=6) or placebo (n=2)
on Day 1
Cohort 4: a single s.c. dose of 0.1 mg/kg of ALX-0141 (n=6) or placebo (n=2) on
Day 1
Cohort 5: a single s.c. dose of 0.3 mg/kg of ALX-0141 (n=6) or placebo (n=2) on
Day 1
Cohort 6: a single s.c. dose of 1 mg/kg of ALX-0141 (n=6) or placebo (n=2) on
Day 1

Procedures:
Pain, light bleeding, heamatoma, possibly an infection.

Medication:
As ALX-0141 will be administered to man for the first time in this study,
adverse effects in man have not been reported to date. In previous studies with
cynomolgus monkeys, in which ALX-0141 was administered in 6 high doses over a
period of 2weeks, the following adverse effect was observed in one animal:
clinical signs of what was thought to be the consequence of low blood calcium
concentration (body tremor and muscle spasm); additionally a mild reaction on
the injection site was seen that spontaneously recovered swiftly.