OC 73.1 - Updated Main Study Period and Long-Term Extension (LTE) Results With Oral Bruton Tyrosine Kinase Inhibitor Rilzabrutinib in Immune Thrombocytopenia (ITP)

Wednesday, July 13, 2022

10:15 AM – 10:30 AM

Location: ExCel Center, ICC Capital Suite Room 14-16

Presentation Format: In-Person

Presenting Author(s)

David J. J. Kuter, MD, DPhil

Director of Clinical Hematology
Hematology Division, Massachusetts General Hospital, Harvard Medical School
Boston, Massachusetts, United States

Co-Author(s)

ME

Merlin Efraim

Hematology
Multiprofile Hospital for Active Treatment Sveta Marina EAD
Varna, Varna, Bulgaria
ZK

Zane Kaplan

Consultant Haematologist
Monash Medical Centre
Clayton, Victoria, Australia
JM

Jiri Mayer

Department head, Department of Internal Medicine, Hematology and Oncology
Department of Internal Medicine, Hematology and Oncology, Masaryk University Hospital
Brno, Jihomoravsky kraj, Czech Republic
Philip Choi, MBBS PhD FRACP FRCPA

Haematologist
Canberra Hospital
Canberra, Australian Capital Territory, Australia
GA

Gerard A. J. Jansen

Internist hematologist
Department of Hematology, Erasmus MC, University Medical Center
Rotterdam, Zuid-Holland, Netherlands
VM

Vickie McDonald, MA MRCP FRCPath PhD

Consultant Haematologist
Barts Health NHS Trust, The Royal London Hospital
London, England, United Kingdom
Ross I. Baker, MD

Professor of Haematology
Health Futures Institute, Murdoch University, Perth, Australia
Perth, Western Australia, Australia
RB

Robert Bird

Director of Haematology
Princess Alexandra Hospital
Woolloongabba, Queensland, Australia
MG

Mamta Garg

Head of Service
Leicester Royal Infirmary
Leicester, England, United Kingdom
JG

Jaromír Gumulec

Deputy Head Physician for Health Care
Department of Hematooncology, University Hospital Ostrava and Faculty of Medicine University of Ostrava
Ostrava, Moravskoslezsky kraj, Czech Republic
MK

Milan Košťál

Fourth Department of Internal Medicine and Hematology, Faculty of Medicine
University Hospital of Hradec Králové
Hradec Králové, Kralovehradecky kraj, Czech Republic
TG

Terry Gernsheimer

Hematology
University of Washington Medical Center
Seattle, Washington, United States
Waleed Ghanima, MD

Professor
Østfold Hospital Foundation
Gralum, Ostfold, Norway
MY

Mengjie Yao

Biostatistics
Sanofi US Services Inc.
Bridgewater, New Jersey, United States
NC

Nichola Cooper

Department of Medicine
Hammersmith Hospital
London, England, United Kingdom
AD

Ahmed Daak

Senior Clinical Research Director
Sanofi Genzyme
Bridgewater, New Jersey, United States

Background: Rilzabrutinib led to rapid and durable platelet responses and was well tolerated in a global phase I/II trial in adult patients with ITP (NCT03395210). We present additional findings observed during the main study period in patients who initiated 400 mg BID as well as patients who are continuing in the LTE.

Aims: Assess efficacy and safety of rilzabrutinib 400 mg BID.

Methods: Patients with 2 baseline platelet counts < 30x10^9/L were required to have responded to ≥1 prior ITP therapy, but at baseline were unable to maintain an adequate response to prior/concomitant therapies. Primary endpoints were safety and efficacy: ≥2 consecutive platelet counts ≥50x10^9/L and increased ≥20x10^9/L from baseline without requiring rescue medication. All patients provided informed consent.

Results: As of 04May2021, 60 patients received rilzabrutinib, 45 initiated a 400 mg BID dose, 16 proceeded to the LTE. At enrollment, patients were heavily pretreated with a median of 4 unique prior therapies. Median ITP duration was 6.1 years and median platelet count was 15x10^9/L. With a median treatment duration of 168 days during the main period, 18 patients (40%) achieved the primary endpoint (Table). In primary responders, platelet counts ≥50x10^9/L were maintained for a median of 72% of the weeks and the median time to first platelet count ≥50x10^9/L was 12.5 days. Figure shows subgroup analysis. Overall, LTE patients received rilzabrutinib for a median of 478 days and 13/14 patients (93%) maintained platelet counts ≥50x10^9/L for ≥50% of their monthly visits in the LTE (Table). Five patients (11%) received rescue medication during the main period + LTE. All treatment-related adverse events were grade 1/2 and transient without related thrombotic events or deaths.

Conclusion(s): Over prolonged treatment, rilzabrutinib 400 mg BID demonstrated a rapid and durable clinical activity and continued to be well-tolerated in patients with ITP.