The purpose of this Phase 2 study is to assess the pharmacokinetics (PK) and safety of RLYB212 in HPA-1b/b pregnant women at higher risk for HPA-1a alloimmunization and FNAIT.
This study is a single-arm, open-label, multicenter study of RLYB212 in HPA-1b/b pregnant participants at higher risk for the occurrence of HPA-1a alloimmunization and FNAIT. A laboratory testing paradigm will be applied at screening to identify women at higher risk for HPA-1a alloimmunization. Study IPA2202 is comprised of three phases: a two-part screening phase, an antenatal treatment phase, and a postpartum follow-up phase. Study duration for each participant is anticipated to be \~44 weeks, inclusive of the screening visits through the Week 10 postpartum visit.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
PREVENTION
Masking
NONE
Enrollment
1
human monoclonal anti-human platelet antigen (HPA)-1a immunoglobulin G antibody
Leids Universitair Medisch Centrum
Leiden, South Holland, Netherlands
Oslo University Hospital- Ullevål
Oslo, Oslo, Norway
Södersjukhuset
Stockholm, Stockholm County, Sweden
Number of Participants With Treatment Related Adverse Events as Defined by CTCAE 5.0
Adverse Events will be collected throughout the study from the time of screening part 2 and beyond until the end of study visit (10 weeks postpartum for the maternal participant and 4-6 weeks of age for the neonate/infant). MedDRA version 27.0 or above will be used to code the AEs. All maternal AEs will be graded according to the National Cancer Institute of Common Terminology Criteria for AEs (CTCAE version 5.0 or higher) and Maternal and Fetal Adverse Event Terminology (MFAET version 1.0 or higher).
Time frame: Approx. Gestational Week (GW) <16, 16, 18, 20, 24, 26, 28, 30, 32, 34, 36, 38; at birth (~40), Post Partum (PP) Week 4, 10 week
Maternal Exposure to RLYB212 as Measured in Serum
The PK profile of RLYB212 during pregnancy following repeat SC administration was evaluated. Results reported in concentration only.
Time frame: Approx. GW 16, 18, 20, 24, 26, 28, 30, 32, 34, 36, 38, at birth (~40), PP Week 4
Neonatal Exposure to RLYB212 as Measured in Cord Blood
The neonatal exposure to RLYB212 was to be measured by sampling and measuring the concentration of RLYB212 in a cord blood sample.
Time frame: At birth (~GW 40)
Number of HPA-1a Positive Neonates With Treatment Related Adverse Events as Defined by CTCAE v5.0
The safety of RLYB212 in the HPA-1a positive neonate would be assessed by treatment related adverse events as defined by CTCAE v5.0
Time frame: At birth (~GW 40), Approx. PP Week 4
Pregnancy Outcomes: Incidence of Live Births, Spontaneous Abortions, Elective Abortions, Still Births or Premature Births
The pregnancy and neonatal outcomes following antenatal RLYB212 administration was assessed by reporting incidence of live births, spontaneous abortions, elective abortions, still births or premature births.
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Time frame: At birth (~GW 40)
Frequency of Neonatal Thrombocytopenia as Measured by Platelet Count Within 72 Hours of Delivery
The occurrence of neonatal thrombocytopenia following antenatal RLYB212 administration was assessed.
Time frame: At birth (~GW 40)
Frequency of HPA-1a Alloimmunization as Measured by Anti-HPA-1a Alloantibodies
The occurrence of HPA-1a alloimmunization was to be assessed by looking for anti-HPA-1a alloantibodies in the woman's blood.
Time frame: Approx. PP Week 10
Neonatal Outcomes: General Health and Overall Status as Defined by Absolute Values and Percentiles
Neonate general health measured by Body Length (for age percentile) , Head Circumference (for age percentile), Weight for Height Percentile (for age percentile)
Time frame: 4-6 weeks following delivery
Participants That Test Positive for Anti-RLYB212 Antibodies as Measured in Their Serum
Participants that test positive for Anti-RLYB212 antibodies as measured in their serum. The immunogenicity of RLYB212 was assessed by testing serum samples for absence or presence of ADAs. The detection and characterization of ADA against RLYB212 will be performed using a validated assay method by or under the supervision of the Sponsor. The titer of confirmed positive samples will be reported as well as the presence of neutralizing antibodies. Other analyses may be performed to verify the stability of antibodies to RLYB212, and/or further characterize the immunogenicity of RLYB212.
Time frame: 16, 20, 24, 28, 32, 36, at birth (~40), PP Week 4