Study of the Efficacy and Safety of Immune Globulin Intravenous (Human) Flebogamma® 5% DIF in Patients With Post-polio Syndrome

This is a phase II/III multicenter, prospective, randomized, placebo-controlled,
double-blind, parallel‑group clinical trial with an adaptive design (flexible group
sequential design with adaptive dose selection) in subjects with PPS.

This study will consist of two stages. The first stage (Stage 1) is for dose selection, and
the second stage (Stage 2) is to establish the superiority (efficacy confirmation) of
Flebogamma 5% DIF and for overall safety analysis. Stage 1 is a 3-arm evaluation of 2 dose
levels of Flebogamma 5% DIF. Flebogamma 5% DIF 2 g/kg of body weight (IVIG 2 g/kg arm), or
the equivalent volume of Normal Saline Solution (40 ml/kg of body weight), or Flebogamma® 5%
DIF 1 g/kg of body weight plus the equivalent volume of Normal Saline Solution (20 ml/kg of
body weight) (IVIG 1 g/kg arm) will be administered every 4 weeks over 2 consecutive days
during a 52-week treatment period. At the end of Stage 2, an interim analysis will be
conducted and 1 of the 2 Flebogamma 5% DIF doses will be selected based on predefined
criteria to be used for Stage 2 .

Stage 2 will consist of 2 treatment arms, the selected dose of Flebogamma® 5% DIF from Stage
1 and Normal Saline Solution (40 ml/kg of body weight). Study drug will be administered every
4 weeks over 2 consecutive days during a 52-week treatment period. During Stage 2, the
selected dose of Flebogamma 5% DIF and Normal Saline Solution will be administered in the
same manner as in Stage 1, including administering the total dose for both treatment arms at
a volume equivalent to that for the IVIG 2 g/kg arm, regardless of the selected dose.

Primary efficacy endpoint will be:

- Physical performance (2MWD) from baseline to the end of the treatment period (at End of
Treatment Visit -Week 52).

Inclusion Criteria:

- Subjects with Body Mass Index less than 35 kg/m^2.

- Subjects meet March-of-Dimes clinical criteria for diagnosis of PPS.

- Subjects who are ambulatory or are able to walk with a cane or other aids or use a
wheelchair (but they are not wheelchair-bound).

- Subjects who have at least 2 newly weakened muscle groups due to PPS (as defined by
medical history), with at least 1 of them in a lower extremity, and having an Medical
Research Council (MRC) scale score greater than 3 at the MMT performed by the
independent assessor at the Screening Visit (SV).

- Female of child-bearing potential must have a negative test for pregnancy.

- Female of child-bearing potential and their sexual partners have agreed to practice
contraception using a method of proven reliability.

- Subjects who are able to walk a 2MWD of at least 50 meters at the SV and Enrollment
Visit/Infusion Visit 1 (EV/IV1)

- Subjects who are able to walk a consistent baseline 2 MWD, that is, the difference in
2MWD between the SV and EV/IV1 is not more than 10%.

Exclusion Criteria:

- Subjects have received human normal immune globulin treatment given by intravenous,
subcutaneous, or intramuscular route within the last 3 years.

- Subjects who are not ambulatory (wheelchair-bound individuals).

- Subjects with poor venous access.

- Subjects with intractable pain requiring narcotics or other psychotropic drugs.

- Subjects with a history of anaphylactic reactions or severe reactions to any
blood-derived product.

- Subjects with a history of intolerance to any component of the investigational
products, such as sorbitol.

- Subjects receiving corticosteroids, except for those who are taking inhaled
corticosteroids for asthma.

- Subjects with a documented diagnosis of hyperviscosity or hypercoagulable state or
thrombotic complications to polyclonal intravenous immunoglobulin (IVIG) therapy in
the past.

- Subjects with a history of recent (within the last year) myocardial infarction,
stroke, or uncontrolled hypertension.

- Subjects who suffer from congestive heart failure, embolism, or electrocardiogram
changes indicative of unstable angina or atrial fibrillation.

- Subjects with a history of chronic alcoholism or illicit drug abuse (addiction) in the
preceding 12 months prior to the SV.

- Subjects with active psychiatric illness that interferes with compliance or
communication with health care personnel.

- Subjects with depression with scores >30 as assessed by the Center for Epidemiologic
Studies Depression validated scale.

- Females who are pregnant or are nursing an infant child.

- Subjects with any medical condition which makes clinical trial participation
unadvisable or which is likely to interfere with the evaluation of the study treatment
and/or the satisfactory conduct of the clinical trial according to the Investigator's
judgment.

- Subjects currently receiving, or have received within 3 months prior to the SV, any
investigational medicinal product or device.

- Subjects who are unlikely to adhere to the protocol requirements, or are likely to be
uncooperative, or unable to provide a storage serum/plasma sample prior to the first
investigational drug infusion.

- Subjects with known selective IgA deficiency and serum antibodies anti-IgA.

- Subjects with renal impairment (i.e., serum creatinine exceeds more than 1.5 time the
upper limit of normal [ULN]).

- Subjects with aspartate aminotransferase or alanine aminotransferase levels exceeding
more than 2.5 times the ULN.

- Subjects with hemoglobin levels <10 g/dL, platelets levels <100,000/mm^3, white blood
cells count <3.0 k/µL, and erythrocyte sedimentation rate >50 mm/h or twice above
normal.

- Subjects with known seropositive to Hepatitis C virus, Human immunodeficiency virus-1
and/or Human immunodeficiency virus-2.

- Subjects with a history of intolerance to fructose.