For patients with high-risk chronic lymphocytic leukemia (CLL), first-line therapy with a triple combination of targeted agents showed encouraging response rates in the phase 2 CLL2-GIVe trial.
Among 41 patients with untreated CLL bearing deleterious TP53 mutations and/or the 17p chromosomal deletion who received the GIVe regimen consisting of obinutuzumab (Gazyva), ibrutinib (Imbruvica), and venetoclax (Venclexta), the complete response rate at final restaging was 58.5%, and 33 patients with a confirmed response were negative for minimal residual disease after a median follow-up of 18.6 months, reported Henriette Huber, MD, of University Hospital Ulm, Germany.
"The GIVe regimen is promising first-line therapy for patients with high-risk CLL," she said in a presentation during the virtual annual congress of the European Hematology Association.
The overall safety profile of the combination was acceptable, she said, but added that "some higher-grade infections are of concern." The rate of grade 3 or greater infections/infestations in the study was 19.5%.
Sound Rationale (With Caveat)
Another adverse event of concern is the rate of atrial fibrillation in the comparatively young patient population (median age 62), noted Alexey Danilov, MD, PhD, of City of Hope in Duarte, Calif., who commented on the study for MDedge.
He pointed out that second-generation Bruton's tyrosine kinase (BTK) inhibitors such as acalabrutinib (Calquence) may pose a lower risk of atrial fibrillation than the BTK inhibitor ibrutinib used in the CLL2-GIVe study.
In general, however, the rationale for the combination is sound, Dr. Danilov said.
"Of all the patient populations that we deal with within CLL, this probably would be most appropriate for this type of therapy. Patients with deletion 17p or TP53 mutations still represent an unmet medical need compared to other patients who don't have those mutations," he said.
Patients with CLL bearing the mutations have lower clinical response rates to novel therapies and generally do not respond well to chemoimmunotherapy, he said.
"The question becomes whether using these all at the same time, versus sequential strategies — using one drug and then after that, at relapse, another — is better, and obviously this trial doesn't address that," he said.
The investigators enrolled 24 men and 17 women with untreated CLL with del(17p) and/or TP53 mutations and adequate organ function (creatinine clearance rate of more than 50 mL/min). The median age was 62 (range 35-85 years); 78% of patients had Binet stage B or C disease. The median Cumulative Illness Rating Scale (CIRS) score was 3 (range 0 to 8).
All patients received treatment with the combination for 6 months. The CD20 inhibitor obinutuzumab was given in a dose of 1,000 mg on days 1, 8, and 15 of cycle 1 and day 1 of cycles 2-6. The BTK inhibitor ibrutinib was given continuously at a dose of 420 mg per day beginning on the first day of the first cycle. Venetoclax, a B-cell lymphoma 2 (BCL-2) inhibitor, was started on day 22 of cycle 1, and was increased to 400 mg per day over 5 weeks until the end of cycle 12.
If patients achieved a complete remission (CR) or CR with incomplete recovery of blood counts (CRi) according to International Workshop on CLL criteria at final restaging (performed with imaging at the end of cycle 12 followed by bone marrow biopsy 2 months later), ibrutinib would be stopped beginning at cycle 15. Patients who did not have a CR or CRi would continue on ibrutinib until cycle 36.
All but 3 of the 41 patients reached final restaging. Analyses of efficacy and safety included all 41 patients.
The CR/CRi rate at final restaging, the primary endpoint, was accomplished in 24 patients (58.8%), and 14 patients (34.1%) had a partial response.
Of the three patients for whom responses could not be assessed, two died (one from ovarian cancer which was retrospectively determined to have been present at enrollment, and one at cycle 9 from cardiac failure), and the third patient withdrew consent at cycle 10.
In all, 33 patients (80.5%) were MRD-negative in peripheral blood, 4 remained MRD positive, and 4 were not assessed. Per protocol, 22 patients with undetectable MRD and a CR or CRi discontinued therapy at week 15. An additional 13 patients also discontinued therapy because of adverse events or other reasons, and 6 remained on therapy beyond cycle 15.
The most frequent adverse events of any grade through the end of cycle 14 were gastrointestinal disorders in 83%, none higher than grade 2; infections and infestations in 70.7%, of which 19.5% were grade 3 or greater in severity; and blood and lymphatic system disorders in 58.5%, most of which (53.7%) were grade 3 or greater.
Cardiac disorders were reported in 19.5% of all patients, including 12.2% with atrial fibrillation; grade 3 or greater atrial fibrillation occurred in 2.4% of patients.
There was one case each of cerebral aspergillosis, progressive multifocal leukoencephalopathy (without PCR testing), urosepsis, staphylococcal sepsis, and febrile infection.
Laboratory confirmed tumor lysis syndrome, all grade 3 or greater, was reported in 9.8% of patients. Infusion-related reactions were reported in 29.3% of patients, with a total of 7.3% being grade 3 or greater.
The trial was supported by Janssen-Cilag and Roche. Dr. Huber disclosed travel reimbursement from Novartis. Dr. Danilov disclosed consulting for AbbVie, Janssen, and Genentech.
European Hematology Association Congress: Abstract S157.
This article originally appeared on MDedge.
Medscape Medical News © 2020
Cite this: Neil Osterweil. Three-Drug Combo Promising Against High-Risk CLL - Medscape - Jun 15, 2020.