American Journal of Hematology recently published the phase 2 study result of BTK (Bruton Tyrosine Kinase) inhibitor orelabrutinib in Relapsed or Refractory Chronic Lymphocytic Leukemia (CLL) / Small Lymphocytic Lymphoma (SLL) patients. The journal concluded that monotherapy of orelabrutinib demonstrated compelling efficacy and a well-tolerated safety profile, with a significant number of patients achieving CR in R/R CLL/SLL.

In the study, 80 eligible patients were enrolled. IRC-assessed overall response rate (ORR) and complete response (CR) was 92.5% and 21.3% respectively. Based on the investigator evaluation, the ORR and CR was 93.8% and 26.3% respectively. The median progression-free survival (PFS) had not been reached, and the 30-month PFS rate and overall survival (OS) rate was 70.9% and 81.3% respectively. Orelabrutinib also revealed substantial response in patients with high prognostic risks: the ORR of patients with del(17p) or TP53 mutation, del(11q), and unmutated immunoglobulin heavy-chain variable region gene (IGHV) was 100%, 94.7%, and 93.9%, respectively.

Patients achieved a quick and sustained response. The median time to first response was 1.9 months. The response rate increased with treatment time. Compared with the data at a median follow-up of 8.7 months, the CR/CRi rate increased from 3.8% to 21.3% and ORR increased from 88.8% to 92.5% at median follow-up of 32.3 months.  

Orelabrutinib demonstrated a well-tolerated safety profile. Most adverse events (AEs) were Grade 1 or 2. Similar to the observation in other studies with orelabrutinib, atrial fibrillation/flutter was not observed in this study.

Professor Jianyong Li, Department of Hematology, Pukou CLL Center, The First Affiliated Hospital of Nanjing Medical University, said, “This study confirmed that orelabrutinib was efficacious in treating R/R CLL/SLL patients, with durable responses and an improved safety profile. As a selective BTK inhibitor with favorable pharmacokinetic and pharmacodynamic properties, orelabrutinib provides an alternative therapeutic option for patients with R/R CLL/SLL.

Chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL), one of the most common types of leukemia, is an indolent malignancy of B lymphocytes, mainly affecting the elderly population. Although CLL/SLL is indolent, some patients will progress over time. There are 191,000 newly diagnosed CLL cases and 61,000 deaths every year globally. Long-term treatment for CLL/SLL is very important, since early discontinuation will compromise the efficacy. A new generation of BTK inhibitors with higher selectivity and improved safety profiles is in urgent need.

The American Journal of Hematology is an academic journal focusing on hematology, which was founded in 1976 and published monthly by WILEY publisher. The journal has been included in SCIE and SCI databases, with an impact factor of 13.268 in 2022.

About Orelabrutinib

Orelabrutinib is a highly selective BTK inhibitor developed by InnoCare for the treatment of cancers and autoimmune diseases.

On Dec. 25 2020, orelabrutinib received conditional approval from the China National Medical Products Administration (NMPA) in two indications: the treatment of patients with relapsed/refractory chronic lymphocytic leukemia (CLL) /small lymphocytic lymphoma (SLL), and the treatment of patients with relapsed/refractory mantle cell lymphoma (MCL). At the end of 2021, orelabrutinib was included into National Reimbursement Drug list to benefit more lymphoma patients.

The supplemental New Drug Applications of orelabrutinib for the treatment of R/R WM and R/R Marginal Zone Lymphoma were accepted in China.

In addition to the approved indications, multi-center, multi-indication clinical trials are underway in the US and China with orelabrutinib as monotherapy or in combination therapies, such as first line treatment of MCD subtype of diffuse large B-cell lymphoma (DLBCL).

Orelabrutinib was granted as Breakthrough Therapy Designation for the treatment of r/r MCL by U.S. Food and Drug Administration (FDA).

In addition, orelabrutinib is also being evaluated in global phase II studies for the treatment of Multiple Sclerosis (MS), and clinical trials for the treatment of SLE, Primary Immune Thrombocytopenia (ITP) and Neuromyelitis Optica Spectrum Disorder (NMOSD) in China.

About InnoCare

InnoCare is a commercial stage biopharmaceutical company committed to discovering, developing, and commercializing first-in-class and/or best-in-class drugs for the treatment of cancer and autoimmune diseases with unmet medical needs in China and worldwide. InnoCare has branches in Beijing, Nanjing, Shanghai, Guangzhou, Hong Kong, and United States.