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| ID | Type | Description | Link |
|---|---|---|---|
| 2024-512651-20-00 | EU Trial (CTIS) Number |
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This study was terminated early by the sponsor due to insufficient drug exposure to achieve the intended therapeutic effect.
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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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| RLYB212 | Experimental | RLYB212 Subcutaneous injection |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Anti-(integrin beta-3) human monoclonal antibody | Drug | human monoclonal anti-human platelet antigen (HPA)-1a immunoglobulin G antibody |
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| Measure | Description | Time Frame |
|---|---|---|
| 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). | 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. | Approx. GW 16, 18, 20, 24, 26, 28, 30, 32, 34, 36, 38, at birth (~40), PP Week 4 |
| Measure | Description | Time Frame |
|---|---|---|
| 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. | At birth (~GW 40) |
| Number of HPA-1a Positive Neonates With Treatment Related Adverse Events as Defined by CTCAE v5.0 |
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Inclusion Criteria:
Pregnant women who present at Gestational Week 6 or after and confirmed to be: HPA-1b/b (HPA-1a negative), HLA-DRB3*01:01 positive, Anti-HPA-1a alloantibody negative, Carrying an HPA-1a/b (HPA-1a positive) fetus
Exclusion Criteria:
Pregnant women
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Leids Universitair Medisch Centrum | Leiden | South Holland | 2333 | Netherlands | ||
| Oslo University Hospital- Ullevål |
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| ID | Title | Description |
|---|---|---|
| FG000 | RLYB212 | RLYB212 Subcutaneous injection |
| Title | Milestones | Reasons Not Completed | |||||
|---|---|---|---|---|---|---|---|
| Overall Study |
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| Type | Includes Protocol | Includes SAP | Includes ICF | Document Label | Document Date | Document Uploaded Date | Document File Name |
|---|---|---|---|---|---|---|---|
| Prot | Yes | No | No | Study Protocol | Oct 14, 2024 | Jan 13, 2026 |
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The safety of RLYB212 in the HPA-1a positive neonate would be assessed by treatment related adverse events as defined by CTCAE v5.0 |
| 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. | 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. | 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. | 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) | 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. | 16, 20, 24, 28, 32, 36, at birth (~40), PP Week 4 |
| Oslo |
| Oslo |
| 0450 |
| Norway |
| Södersjukhuset | Stockholm | Stockholm County | 118 83 | Sweden |
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| NOT COMPLETED |
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| ID | Title | Description |
|---|---|---|
| BG000 | RLYB212 | RLYB212 Subcutaneous injection |
| Units | Counts |
|---|---|
| Participants |
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| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Age, Categorical | Count of Participants | Participants |
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| Sex: Female, Male | Participants were pregnant woman | Count of Participants | Participants |
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| Race (NIH/OMB) | Count of Participants | Participants |
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| Ethnicity (NIH/OMB) | Count of Participants | Participants |
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| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | 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). | This is reported as the number of participants that experienced as AE over the entire study duration. Enrollment in the study was terminated after enrolling one pregnant woman. Dosing with RLYB212 was stopped after the administration of two doses of the planned 7 due to the inability to measure drug concentrations in the blood samples. The participant was followed for safety assessments only starting at GW 24. | Posted | Count of Participants | Participants | 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 |
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| Primary | 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. | Gestational weeks 16, 18, 20, and 24 PK concentrations are reported (0 = BLQ). Blood samples were not collected for GWs 26, 28, 30, 32, 34, 36, 38, at birth (~40), PP Week 4. Enrollment in the study was terminated after enrolling one pregnant woman. Dosing with RLYB212 was stopped after the administration of two doses of the planned 7 due to the inability to measure drug concentrations in the blood samples. The participant was followed for safety assessments only starting at GW 24. | Posted | Number | ng/mL | Approx. GW 16, 18, 20, 24, 26, 28, 30, 32, 34, 36, 38, at birth (~40), PP Week 4 |
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| Secondary | 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. | No data is reported for this outcome since the sample was inadvertently not collected from the single enrolled participant. Enrollment in the study was terminated after enrolling one pregnant woman. Dosing with RLYB212 was stopped after the administration of two doses of the planned 7 due to the inability to measure drug concentrations in the blood samples. The participant was followed for safety assessments only starting at gestational week 24. | Posted | Count of Participants | Participants | At birth (~GW 40) |
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| Secondary | 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 | Posted | Number | participants | At birth (~GW 40), Approx. PP Week 4 |
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| Secondary | 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. | The outcome for the one pregnancy is reported here. Enrollment in the study was terminated after enrolling one pregnant woman. | Posted | Count of Participants | Participants | At birth (~GW 40) |
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| Secondary | 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. | No results are reported for the outcome as the sample was inadvertently not collected at the time of birth. Enrollment in the study was terminated after enrolling one pregnant woman. | Posted | Count of Participants | Participants | At birth (~GW 40) |
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| Secondary | 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. | No blood sample was collected for this outcome. Enrollment in the study was terminated after enrolling one pregnant woman. Dosing with RLYB212 was stopped after the administration of two doses of the planned 7 due to the inability to measure drug concentrations in the blood samples. The participant was followed for safety assessments only starting at GW 24. | Posted | Count of Participants | Participants | Approx. PP Week 10 |
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| Secondary | 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) | Results are provided for the single participants neonate only, no analyses were possible due to termination of the study. | Posted | Number | Percentile | 4-6 weeks following delivery |
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| Secondary | 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. | Participants that test positive at gestational weeks 16, 20, 24, and at birth are reported. Blood samples were not collected for GWs 28, 32, 36, and PP Week 4. Enrollment in the study was terminated after enrolling one pregnant woman. Dosing with RLYB212 was stopped after the administration of two doses of the planned 7 due to the inability to measure drug concentrations in the blood samples. The participant was followed for safety with unnecessary blood draws stopped. | Posted | Count of Participants | Participants | 16, 20, 24, 28, 32, 36, at birth (~40), PP Week 4 |
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Until end of study (up to 10 weeks postpartum)
AEs will be spontaneously reported by the participant in response to general questions of how they are feeling. Specific new AEs will not be solicited, although follow -up questions about prior AEs should be asked if not volunteered spontaneously by the participant.
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | RLYB212 | RLYB212 Subcutaneous injection | 0 | 1 | 0 | 1 | 1 | 1 |
| EG001 | Infant of Woman Treated With RLYB212 | Infant of woman treated with RLYB212 | 0 | 1 | 0 | 1 | 1 | 1 |
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| Term | Organ System | Source Vocabulary | Assessment Type | Notes | Statistical Information |
|---|---|---|---|---|---|
| Influenza | Infections and infestations | Systematic Assessment |
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| RASH IN LOWER EXTREMITIES | Skin and subcutaneous tissue disorders | Systematic Assessment |
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| GENITAL HERPES REACTIVATION | Infections and infestations | Systematic Assessment |
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| CARDIAC MURMUR GRAD 2-3 | Investigations | Systematic Assessment |
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This study was terminated early by the sponsor due to insufficient drug exposure to achieve the intended therapeutic effect. Only one participant (pregnant woman) was enrolled in the study prior to the sponsor's decision to terminate. This participant successfully delivered one neonate. Given the premature study termination and enrollment of a single mother-infant pair, the planned statistical analyses were not performed.
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| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Head of Development Operations | Rallybio IPA, LLC | +1 203-859-3820 | clinicaltrials@rallybio.com |
| Prot_000.pdf |
| SAP | No | Yes | No | Statistical Analysis Plan | Sep 8, 2025 | Jan 13, 2026 | SAP_001.pdf |
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| ID | Term |
|---|---|
| D054098 | Thrombocytopenia, Neonatal Alloimmune |
| ID | Term |
|---|---|
| D013921 | Thrombocytopenia |
| D001791 | Blood Platelet Disorders |
| D006402 | Hematologic Diseases |
| D006425 | Hemic and Lymphatic Diseases |
| D000095542 | Cytopenia |
| D007232 | Infant, Newborn, Diseases |
| D009358 | Congenital, Hereditary, and Neonatal Diseases and Abnormalities |
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| Native Hawaiian or Other Pacific Islander |
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| Black or African American |
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| White |
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| More than one race |
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| Unknown or Not Reported |
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| Unknown or Not Reported |
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