Positron emission tomography (PET)-adapted chemotherapy and radiotherapy approaches are currently used for the initial treatment of early-stage Hodgkin lymphoma (HL) with progression-free survival ...and overall survival exceeding 85% and 95%, respectively. However, despite general agreement on the prognostic value of interim PET in HL, frontline treatment approaches vary among institutions with respect to how pretreatment clinical risk factors determine treatment selection, the definition of PET negativity, which chemotherapy regimen to initiate and how many cycles to administer, and when to incorporate radiation. Furthermore, as recent trials have confirmed improved efficacy and manageable toxicity when brentuximab and checkpoint inhibitors are combined with frontline regimens such as doxorubicin, vinblastine, and dacarbazine in advanced-stage HL, these agents are now under evaluation as frontline therapy in early-stage HL. A number of issues will affect the use of these agents in early-stage HL, including the costs, early and late toxicities with these agents, patient population (favorable or unfavorable risk groups), how to incorporate them (concurrently or sequentially), and whether they can ultimately replace cytotoxic therapy with similar efficacy and fewer late effects. Future treatment paradigms for early-stage HL may change significantly once randomized studies are completed incorporating these agents into frontline therapy. Ideally, frontline use of brentuximab and checkpoint inhibitors in early-stage HL will result in improved outcomes compared with current PET-adapted approaches with decreased risks of late toxicities that continue to afflict long-term survivors of HL.
In some patients with CLL, resistance to the BTK inhibitor ibrutinib develops. Two classes of resistance mutations have been found: the more common involves alteration of the drug-binding site to ...make binding reversible; the less common activates a downstream kinase that effectively bypasses BTK.
The development of B-cell–receptor antagonists has been a therapeutic advance in chronic lymphocytic leukemia (CLL). Although B-cell–receptor ligation in normal cells induces proliferation, apoptosis, or anergy,
1
pathway dysregulation in CLL results in the propagation of proliferative and prosurvival signals.
2
,
3
Several agents targeting the B-cell–receptor pathway are in development, including the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib. Although
BTK
is not recurrently mutated in CLL,
4
,
5
it is up-regulated at the transcript level and is constitutively active.
6
,
7
Ibrutinib irreversibly binds BTK at the C481 residue, rendering it kinase-inactive, inducing modest CLL-cell apoptosis, and abolishing proliferation and B-cell–receptor signaling in . . .
B-cell receptor (BCR) signaling is aberrantly activated in chronic lymphocytic leukemia (CLL). Bruton tyrosine kinase (BTK) is essential to BCR signaling and in knockout mouse models its mutation has ...a relatively B cell–specific phenotype. Herein, we demonstrate that BTK protein and mRNA are significantly over expressed in CLL compared with normal B cells. Although BTK is not always constitutively active in CLL cells, BCR or CD40 signaling is accompanied by effective activation of this pathway. Using the irreversible BTK inhibitor PCI-32765, we demonstrate modest apoptosis in CLL cells that is greater than that observed in normal B cells. No influence of PCI-32765 on T-cell survival is observed. Treatment of CD40 or BCR activated CLL cells with PCI-32765 results in inhibition of BTK tyrosine phosphorylation and also effectively abrogates downstream survival pathways activated by this kinase including ERK1/2, PI3K, and NF-κB. In addition, PCI-32765 inhibits activation-induced proliferation of CLL cells in vitro, and effectively blocks survival signals provided externally to CLL cells from the microenvironment including soluble factors (CD40L, BAFF, IL-6, IL-4, and TNF-α), fibronectin engagement, and stromal cell contact. Based on these collective data, future efforts targeting BTK with the irreversible inhibitor PCI-32765 in clinical trials of CLL patients is warranted.
Despite the success of standard front-line chemotherapy for classical Hodgkin lymphoma (cHL), a subset of these patients, particularly those with poor prognostic factors at diagnosis (including the ...presence of B symptoms, bulky disease, advanced stage, or extranodal disease), relapse. For those patients who relapse following autologous stem cell transplant (SCT), multiple treatment options are available, including single-agent chemotherapy, combination chemotherapy strategies, radiotherapy, the immunoconjugate brentuximab, checkpoint inhibitors nivolumab and pembrolizumab, lenalidomide, everolimus, or observation in selected patients. In patients with an available donor, allogeneic SCT may also be considered. With numerous treatment options available, we advocate for a tailored therapeutic approach for patients with relapsed cHL guided by patient-specific characteristics including age, comorbidities, sites of disease (nodal or organ), previous chemosensitivity, and goals of treatment (long-term disease control vs allogeneic SCT).
Single-agent ibrutinib is active in patients with previously treated mantle cell lymphoma (MCL); however, nearly half of all patients experience treatment failure during the first year. We previously ...demonstrated that prolonged early G1 cell cycle arrest induced by the oral, specific CDK4/6 inhibitor palbociclib can overcome ibrutinib resistance in primary human MCL cells and MCL cell lines expressing wild-type Bruton's tyrosine kinase (BTK). Therefore, we conducted a phase 1 trial to evaluate the dosing, safety, and preliminary activity of palbociclib plus ibrutinib in patients with previously treated mantle cell lymphoma. From August 2014 to June 2016, a total of 27 patients (21 men, 6 women) were enrolled. The maximum tolerated doses were ibrutinib 560 mg daily plus palbociclib 100 mg on days 1 to 21 of each 28-day cycle. The dose-limiting toxicity was grade 3 rash. The most common grade 3 to 4 toxicities included neutropenia (41%), thrombocytopenia (30%), hypertension (15%), febrile neutropenia (15%), and lung infection (11%). The overall and complete response rates were 67% and 37%, and with a median follow-up of 25.6 months, the 2-year progression-free survival was 59.4% and the 2-year response duration was 69.8%. A phase 2 multicenter clinical trial to further characterize efficacy is now ongoing. The current trial was registered at www.clinicaltrials.gov as #NCT02159755.
•Ibrutinib 560 mg daily plus palbociclib 100 mg on days 1 to 21 of each 28-day cycle could be safely administered to patients with previously treated MCL.•Complete responses and duration of response (median, >2 years) were high relative to studies of single-agent ibrutinib.
Display omitted
Summary Background Chemoimmunotherapy has led to improved numbers of patients achieving disease response, and longer overall survival in young patients with chronic lymphocytic leukaemia; however, ...its application in elderly patients has been restricted by substantial myelosuppression and infection. We aimed to assess safety and activity of ibrutinib, an orally administered covalent inhibitor of Bruton tyrosine kinase (BTK), in treatment-naive patients aged 65 years and older with chronic lymphocytic leukaemia. Methods In our open-label phase 1b/2 trial, we enrolled previously untreated patients at clinical sites in the USA. Eligible patients were aged at least 65 years, and had symptomatic chronic lymphocytic leukaemia or small lymphocytic lymphoma requiring therapy. Patients received 28 day cycles of once-daily ibrutinib 420 mg or ibrutinib 840 mg. The 840 mg dose was discontinued after enrolment had begun because comparable activity of the doses has been shown. The primary endpoint was the safety of the dose-fixed regimen in terms of frequency and severity of adverse events for all patients who received treatment. This study is registered with ClinicalTrials.gov , number NCT01105247. Findings Between May 20, 2010, and Dec 18, 2012, we enrolled 29 patients with chronic lymphocytic leukaemia and two patients with small lymphocytic lymphoma. Median age was 71 years (range 65–84), and 23 (74%) patients were at least 70 years old. Toxicity was mainly of mild-to-moderate severity (grade 1–2). 21 (68%) patients had diarrhoea (grade 1 in 14 45% patients, grade 2 in three 10% patients, and grade 3 in four 13% patients). 15 (48%) patients developed nausea (grade 1 in 12 39% patients and grade 2 in three 10% patients). Ten (32%) patients developed fatigue (grade 1 in five 16% patients, grade 2 in four 13% patients, and grade 3 in one 3% patient). Three (10%) patients developed grade 3 infections, although no grade 4 or 5 infections occurred. One patient developed grade 3 neutropenia, and one developed grade 4 thrombocytopenia. After a median follow-up of 22·1 months (IQR 18·4–23·2), 22 (71%) of 31 patients achieved an objective response (95% CI 52·0–85·8); four patients (13%) had a complete response, one patient (3%) had a nodular partial response, and 17 (55%) patients had a partial response. Interpretation The safety and activity of ibrutinib in elderly, previously untreated patients with symptomatic chronic lymphocytic leukaemia, or small lymphocytic lymphoma is encouraging, and merits further investigation in phase 3 trials. Funding Pharmacyclics, Leukemia and Lymphoma Society, D Warren Brown Foundation, Mr and Mrs Michael Thomas, Harry Mangurian Foundation, P50 CA140158 to Prof J C Byrd MD.
Ibrutinib is an orally administered inhibitor of Bruton tyrosine kinase that antagonizes B-cell receptor, chemokine, and integrin-mediated signaling. In early-phase studies, ibrutinib demonstrated ...high response rates and prolonged progression-free survival (PFS) in chronic lymphocytic leukemia (CLL). The durable responses observed with ibrutinib relate in part to a modest toxicity profile that allows the majority of patients to receive continuous therapy for an extended period. We report on median 3-year follow-up of 132 patients with symptomatic treatment-naïve and relapsed/refractory CLL or small lymphocytic lymphoma. Longer treatment with ibrutinib was associated with improvement in response quality over time and durable remissions. Toxicity with longer follow-up diminished with respect to occurrence of grade 3 or greater cytopenias, fatigue, and infections. Progression remains uncommon, occurring primarily in some patients with relapsed del(17)(p13.1) and/or del(11)(q22.3) disease. Treatment-related lymphocytosis remains largely asymptomatic even when persisting >1 year and does not appear to alter longer-term PFS and overall survival compared with patients with partial response or better. Collectively, these data provide evidence that ibrutinib controls CLL disease manifestations and is well tolerated for an extended period; this information can help direct potential treatment options for different subgroups to diminish the long-term risk of relapse.
•Three-year follow-up of ibrutinib in CLL demonstrated continued activity with durable responses that improve in quality with extended treatment.•Toxicity diminished over time with respect to grade ≥3 cytopenias, fatigue, infections, and adverse events leading to discontinuation.
With the recent success of the Bruton's tyrosine kinase (BTK) inhibitor, ibrutinib, and the phosphoinositide-3-kinase (PI3K) inhibitor, idelalisib, in the treatment of patients with relapsed or ...refractory non-Hodgkin's lymphoma (NHL), a number of new agents targeting the B-cell receptor (BCR) pathway are in clinical development. In addition, multiple trials combining these agents with conventional cytotoxic chemotherapy, immunomodulatory agents, monoclonal antibodies, or other kinase inhibitors are underway. This review will summarize the current data with the use of single agent and combination therapy with BCR inhibitors in NHL. In addition, commonly encountered as well as serious toxicities and hypothesized resistance mechanisms will be discussed. Lastly, this review will examine the future of these agents and opportunities to maneuver them into the front-line setting in selected NHL subtypes.
Although most investigators are well aware of the incredible success of brentuximab vedotin in the treatment of patients with Hodgkin lymphoma (HL) and anaplastic large-cell lymphoma (ALCL), the ...study by Jacobsen and colleagues in this issue of Blood demonstrates surprising activity of this agent in patients with B-cell non-Hodgkin lymphoma (NHL).
PDF
