A Phase 2a Study Evaluating BIVV020 in Adults With Persistent/Chronic Immune Thrombocytopenia (ITP)

A naive participant was a participant who did not use sutimlimab prior to enrollment. A switcher was a participant who used sutimlimab prior to enrollment. A naive participant was a responder if the platelet count was \>=50 × 10\^9/liter (L) at \>=50 percent (%) of scheduled visits, or for participants with baseline platelet count \<15 × 10\^9/L, a \>=20 × 10\^9/L increase in platelet count from baseline at \>=50% of scheduled visits, without receiving rescue immune thrombocytopenia (ITP) therapy. A switcher was a responder if the maintenance platelet count was \>=30 × 10\^9/L at \>=50% of scheduled visits, without receiving rescue ITP therapy.

Time frame: From Week 3 to Week 24

Population: Results are based on the overall number of participants analyzed = intent-to-treat (ITT) population which consisted of all exposed participants. Number analyzed = number of participants for each category (naive participant and switcher).

Plasma samples were analyzed for the presence of ADAs for SAR445088 (BIVV020) using validated assays. Treatment-induced ADA was defined as ADAs that developed during the treatment-emergent period and without pre-existing ADA. Pre-existing ADA was defined as ADAs present in samples drawn before first study treatment administration. Treatment-boosted ADA positive was defined as pre-existing ADA (i.e., ADA positive at baseline) that was boosted at least a 9-fold increase of titer values during the treatment-emergent period than the baseline. Treatment-emergent ADA positive was defined as either treatment-induced ADA positive or treatment-boosted ADA positive during the treatment-emergent period. Inconclusive ADA was defined as the one that could not irrefutably be classified as with or without treatment-emergent ADA.

Time frame: Up to Week 103

Population: The ADA population consisted of all enrolled and treated participants (safety population) with at least 1 post-baseline ADA sample.

Criteria for PCSA: Blood Urea Nitrogen: \>=17 millimole (mmol)/L; Creatinine: \>=150 micromole (mcmol)/L (Adults), \>=30% and \<100% change from baseline, \>=100% change from baseline; Potassium: \<3 mmol/L, \>=5.5 mmol/L; Sodium: \<=129 mmol/L, \>=160 mmol/L; Aspartate Aminotransferase (AST): \>3 ULN, \>5 ULN, \>10 ULN, \>20 ULN; Alanine Aminotransferase (ALT): \>3 ULN, \>5 ULN, \>10 ULN, \>20 ULN; Alkaline Phosphatase (ALP): \>1.5 ULN; Bilirubin: \>1.5 ULN, \>2 ULN; ALT and Total Bilirubin: ALT \>3 ULN and TBILI \>2 ULN. Only the worst case during the TE period for each participant with worsening from baseline is presented.

Time frame: On Days 1, 15, 29, Weeks 8, 12 and 24, then every 8 weeks until the EOS (Week 103)

Population: The Safety population consisted of all enrolled participants who took at least 1 dose (including partial dose) of study treatment.

The number of participants with PCSA for coagulation parameters during the TE period without PCSA definition by biological function are presented. The parameters evaluated were prothrombin time, prothrombin international normalized ratio and activated partial thromboplastin time (APTT).

Time frame: On Days 1, 15, 29, Weeks 8, 12 and 24, then every 8 weeks until the EOS (Week 103)

Population: Overall number of participants analyzed = Number of participants in the 'safety population' with available data for this outcome measure. Number analyzed = number of participants in the 'safety population' with available data for the corresponding categories. Some participants in 'Number Analyzed' were common for 2 or for all the 3 categories (Prothrombin time, Prothrombin International Normalized Ratio and APTT).

Criteria for potentially clinically significant laboratory abnormalities (PCSA): White blood cells: less than (\<)3.0 Giga/L (Non-Black \[NB\]) or \<2.0 Giga/L (Black \[B\]), greater than or equal to (\>=)16.0 Giga/L; Lymphocytes: greater than (\>)4.0 Giga/L; Neutrophils: \<1.5 Giga/L (NB) or \<1.0 Giga/L (B); Monocytes: \>0.7 Giga/L; Basophils: \>0.1 Giga/L; Eosinophils: \>0.5 Giga/L or \>upper limit of normal (ULN) (if ULN \>=0.5 Giga/L); Hemoglobin: less than or equal to (\<=) 115 grams per liter (g/L) (Male\[M\]) or \<=95 g/L (Female\[F\]), \>=185 g/L (M) or \>=165 g/L (F), Decrease from baseline (DFB) \>=20 g/L; Hematocrit: \<=0.37 volume/volume (v/v) (M) or \<=0.32 v/v (F); Red blood cells (RBC): \>=6 Tera/L; Platelets:\<100 Giga/L, \>=700 Giga/L. Only the worst case during the treatment-emergent (TE) period for each participant with worsening from baseline is presented.

Time frame: On Days 1, 15, 29, at Weeks 8, 12, 24, and then every 8 weeks until the end of study (EOS) (Week 103)

Population: Overall number of participants analyzed = safety population. Number analyzed = number of participants in the 'safety population' with available data for the corresponding categories. The Safety population consisted of all enrolled participants who took at least 1 dose (including partial dose) of study treatment. Only those participants with data available were analyzed.

Criteria for PCSA: potential of Hydrogen (pH) \<=4.6, \>=8. Only the worst case during the TE period for each participant with worsening from baseline is presented.

Time frame: On Days 1, 15, 29, Weeks 8, 12 and 24, then every 8 weeks until the EOS (Week 103)

Population: The Safety population consisted of all enrolled participants who took at least 1 dose (including partial dose) of study treatment.

An AE was defined as any untoward medical occurrence in a participant temporally associated with the use of study treatment, whether or not considered related to the study treatment. SAEs were any untoward medical occurrence that at any dose: resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, was a medically important event. TEAEs were AEs that developed after the first study treatment administration in the safety analysis period which was defined as the period from the first study intervention administration to the end of study (EOS) visit (up to Week 103).

Time frame: From first study treatment administration (Day 1) up to Week 103

Population: The Safety population consisted of all enrolled participants who took at least 1 dose (including partial dose) of study treatment.

A participant was a responder if the platelet count was \>=50 × 10\^9/L and there was a greater than 2-fold increase from baseline, measured on 2 occasions at least 7 days apart with the absence of bleeding \[bleeding score \>=2 on the World Health Organization (WHO) bleeding scale\] while the platelet counts were maintained above the threshold and lack of combination ITP therapy during this period. WHO bleeding scores: 1=Petechiae; 2=Mild blood loss; 3=Gross blood loss; and 4=Debilitating blood loss.

Time frame: At Weeks 24 and 56

Population: The ITT population consisted of all exposed participants.

Data was collected to assess the effect of treatment with SAR445088 (BIVV020) on the requirement for rescue ITP therapy.

Time frame: Up to Week 84

Population: The ITT population consisted of all exposed participants.

Plasma samples were collected at specified timepoints.

Time frame: 1-hour post-dose on Day 1, on Days 8, 15, 29, 43, at Weeks 12, 16, 24, 32, 40, 48, 56, 64, 72, 80 and EOS visit, up to 103 weeks

Population: The Pharmacokinetic (PK) population consisted of all enrolled and treated participants (safety population) with at least 1 post-baseline PK sample. Only those participants with data available were included in the analysis.

Time to first platelet response was defined as greater than or equal to each of the following values: 50 × 10\^9/L or 100 × 10\^9/L (confirmed by 2 measurements at least 7 days apart). It was calculated as date of first occurrence of confirmed platelet count response before rescue therapy.

Time frame: From Baseline (Day 1) up to Week 56

Population: Overall number of participants analyzed = ITT Population which consisted of all exposed participants. Number analyzed = number of participants in the 'ITT Population' who met the specified platelet counts (\>=50 x10\^9/L or \>=100 x10\^9/L) as confirmed by 2 measurements at least 7 days apart. Participants who met the criteria 'Platelet count \>=100 x10\^9/L' were the same as who met the criteria 'Platelet count \>=50 x10\^9/L'.