ORLANDO – A novel Bruton tyrosine kinase inhibitor has produced favorable results in patients with relapsed or refractory mantle cell lymphoma, according to findings presented at the annual meeting of the American Society of Hematology.
In a phase 2 trial, orelabrutinib produced an overall response rate of 86% and a 12-month progression-free survival rate of 64%. Safety results with orelabrutinib were superior to historical results with ibrutinib.
The efficacy and safety profile of orelabrutinib, as well as its “convenient” dosing, may make it the “preferred therapeutic choice for B-cell malignancy,” said Lijuan Deng, MD, PhD, of Peking University Cancer Hospital & Institute, Beijing, who presented the phase 2 trial of orelabrutinib at ASH 2019.
The trial enrolled 106 patients with relapsed/refractory mantle cell lymphoma who were treated at 22 centers in China. At baseline, the patients had a median age of 62 years (range, 37-73 years), and 79.2% were men. Most patients (94.4%) had stage III-IV disease.
Prior therapies included CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone)-based (69.8%), EPOCH (etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin)-based (22.6%), DHAP (dexamethasone, cytarabine, and cisplatin)-based (22.6%), CVAD (cyclophosphamide, vincristine, doxorubicin, dexamethasone)-based (12.3%), and ESHAP (etoposide, methylprednisolone, cytarabine, and cisplatin)-based (4.7%) regimens, and 88.7% of patients had received prior anti-CD20 therapy.
Patients received orelabrutinib at 100 mg twice daily (n = 20) or 150 mg once a day (n = 86). All 106 patients were evaluable for safety, and 99 were evaluable for efficacy.
“Orelabrutinib achieved high response and durable remissions,” Dr. Deng said.
The overall response rate was 85.9% in the evaluable efficacy population and 83.5% in the 150-mg dosing arm. The complete response rates were 27.3% and 29.1%, respectively. The median time to response, overall, was 1.9 months.
The median duration of response and median progression-free survival were not reached at a median follow-up of 10.5 months. At 12 months, 74.3% of patients were still in response, and the progression-free survival rate was 64%.
Most adverse events were grade 1-2 in nature. The most common grade 3 or higher events were platelet count decrease (11.3%), neutrophil count decrease (8.5%), anemia (7.5%), hypertension (3.8%), pneumonia (2.8%), white blood count decrease (1.9%), and hypokalemia (1.9%).
Adverse events of interest included grade 3 or higher hypertension (3.8%), diarrhea (6.6%), and infection (10.4%), as well as secondary malignancy (0.9%, n = 1). There were no cases of grade 3 or higher hemorrhage, grade 3 or higher atrial fibrillation/flutter, or grade 5 treatment-related adverse events.
Dr. Deng noted that rates of grade 3 or higher hemorrhage, atrial fibrillation, diarrhea, and infection, as well as rates of secondary malignancies, have historically been higher with ibrutinib (; ).
“Orelabrutinib has an improved safety profile in patients with relapsed or refractory mantle cell lymphoma,” Dr. Deng said. “The most common adverse events were cytopenia and infections, which are considered mechanism based.”
The study was sponsored by InnoCare Pharma. Dr. Deng reported having no conflicts of interest.
SOURCE: Deng L et al. ASH 2019,