Inhibition of the phosphatidylinositol-3-kinase (PI3K) pathway as an anticancer therapeutic strategy was realized with the approval of the orally bioavailable small molecule PI3Kδ inhibitor ...idelalisib. In this focused review, we highlight the rationale for targeting the pathway in lymphomas, provide a brief summary of the preclinical data, and describe the clinical experience with this agent in patients with lymphoma. We describe some of the idiosyncratic toxicities of this agent, some of the mechanisms of resistance, and some of the ongoing combination strategies.
Lenalidomide is an orally active immunomodulatory drug that has direct antineoplastic activity and indirect effects mediated through multiple types of immune cells found in the tumor ...microenvironment, including B, T, natural killer (NK), and dendritic cells. Recently, the E3 ubiquitin ligase cereblon was identified as a molecular target that may underlie the effects of lenalidomide on tumor cells, as well as on cells in the tumor microenvironment. Decreases in cereblon attenuate these effects and also confer resistance to lenalidomide. Tumoricidal effects of lenalidomide are associated with reduced interferon regulatory factor 4, a downstream target of cereblon. Lenalidomide stimulates proliferation and activation of NK cells, thereby enhancing NK cell-mediated cytotoxicity and antibody-dependent cellular cytotoxicity. These effects appear to be secondary to cytokine production from T cells. Lenalidomide has been shown to produce synergistic effects in experimental models when evaluated in combination with rituximab, dexamethasone, bortezomib, and B-cell receptor signaling inhibitors, consistent with mechanisms complementary to these agents. These experimental findings have translated to the clinic, where single-agent use displays durable responses in relapsed/refractory non-Hodgkin lymphoma, and combination with rituximab and other agents leads to improved responses at first line and in relapsed/refractory disease. The activity of lenalidomide is evident across multiple lymphoma subtypes, including indolent and aggressive forms. The interaction among cell types in the immune microenvironment is increasingly recognized as important to tumor cell recognition and destruction, as well as to protection of normal immune cells, as reflected by lenalidomide studies across multiple types of B-cell lymphomas.
Patients with indolent non-Hodgkin lymphoma typically respond well to first-line immunochemotherapy. At relapse, single-agent rituximab is commonly administered. Data suggest the immunomodulatory ...agent lenalidomide could increase the activity of rituximab.
A phase III, multicenter, randomized trial of lenalidomide plus rituximab versus placebo plus rituximab was conducted in patients with relapsed and/or refractory follicular or marginal zone lymphoma. Patients received lenalidomide or placebo for 12 cycles plus rituximab once per week for 4 weeks in cycle 1 and day 1 of cycles 2 through 5. The primary end point was progression-free survival per independent radiology review.
A total of 358 patients were randomly assigned to lenalidomide plus rituximab (n = 178) or placebo plus rituximab (n = 180). Infections (63%
49%), neutropenia (58%
23%), and cutaneous reactions (32%
12%) were more common with lenalidomide plus rituximab. Grade 3 or 4 neutropenia (50%
13%) and leukopenia (7%
2%) were higher with lenalidomide plus rituximab; no other grade 3 or 4 adverse event differed by 5% or more between groups. Progression-free survival was significantly improved for lenalidomide plus rituximab versus placebo plus rituximab, with a hazard ratio of 0.46 (95% CI, 0.34 to 0.62;
< .001) and median duration of 39.4 months (95% CI, 22.9 months to not reached) versus 14.1 months (95% CI, 11.4 to 16.7 months), respectively.
Lenalidomide improved efficacy of rituximab in patients with recurrent indolent lymphoma, with an acceptable safety profile.
Survival and progression of mature B-cell malignancies depend on signals from the B-cell antigen receptor, and Bruton tyrosine kinase (BTK) is a critical signaling kinase in this pathway. We ...evaluated ibrutinib (PCI-32765), a small-molecule irreversible inhibitor of BTK, in patients with B-cell malignancies.
Patients with relapsed or refractory B-cell lymphoma and chronic lymphocytic leukemia received escalating oral doses of ibrutinib. Two schedules were evaluated: one, 28 days on, 7 days off; and two, once-daily continuous dosing. Occupancy of BTK by ibrutinib in peripheral blood was monitored using a fluorescent affinity probe. Dose escalation proceeded until either the maximum-tolerated dose (MTD) was achieved or, in the absence of MTD, until three dose levels above full BTK occupancy by ibrutinib. Response was evaluated every two cycles.
Fifty-six patients with a variety of B-cell malignancies were treated over seven cohorts. Most adverse events were grade 1 and 2 in severity and self-limited. Dose-limiting events were not observed, even with prolonged dosing. Full occupancy of the BTK active site occurred at 2.5 mg/kg per day, and dose escalation continued to 12.5 mg/kg per day without reaching MTD. Pharmacokinetic data indicated rapid absorption and elimination, yet BTK occupancy was maintained for at least 24 hours, consistent with the irreversible mechanism. Objective response rate in 50 evaluable patients was 60%, including complete response of 16%. Median progression-free survival in all patients was 13.6 months.
Ibrutinib, a novel BTK-targeting inhibitor, is well tolerated, with substantial activity across B-cell histologies.
Chimeric antigen receptor (CAR) T-cell therapy targeting CD19 may be associated with long-term adverse effects such as cytopenia and immune deficiency. In order to characterize these late events, we ...analyzed 31 patients with relapsed or refractory large B-cell lymphoma treated with axicabtagene ciloleucel at our institution on two clinical trials, ZUMA-1 (clinicaltrials gov. Identifier: NCT02348216) and ZUMA-9 (clinicaltrials gov. Identifier: NCT03153462). Complete blood counts, lymphocyte subsets, and immunoglobulin levels were measured serially until month 24 or progression. Fifteen (48%) patients had grade 3-4 cytopenia, including anemia (five, 16%), neutropenia (nine, 29%), or thrombocytopenia (13, 42%) at day 30. Cytopenia at day 30 was not significantly associated with later diagnosis of myelodysplasia. Among patients with ongoing remission, grade 3-4 cytopenia was observed in one of nine (11%) at 2 years. While peripheral CD8+ T cells recovered early, CD4+ T-cell recovery was delayed with a count of <200/mL in three of nine (33%) patients at 1 year and two of seven (29%) at 2 years. Immunoglobulin G levels normalized in five of nine (56%) patients at 2 years. Thirteen (42%) patients developed grade 3-4 infectious complications, including herpes zoster and Pneumocystis jiroveci pneumonia. These results suggest the need for prolonged monitoring and prophylaxis against opportunistic infections in these patients, to improve the longterm safety of axicabtagene ciloleucel therapy.
Ibrutinib, an inhibitor of Bruton's tyrosine kinase, and venetoclax, an inhibitor of B-cell lymphoma 2 protein, have been approved for patients with chronic lymphocytic leukemia (CLL). Preclinical ...investigations have indicated potential synergistic interaction of their combination.
We conducted an investigator-initiated phase 2 study of combined ibrutinib and venetoclax involving previously untreated high-risk and older patients with CLL. All patients had at least one of the following features: chromosome 17p deletion, mutated
, chromosome 11q deletion, unmutated
, or an age of 65 years or older. Patients received ibrutinib monotherapy (420 mg once daily) for 3 cycles, followed by the addition of venetoclax (weekly dose escalation to 400 mg once daily). Combined therapy was administered for 24 cycles. Response assessments were performed according to International Workshop on Chronic Lymphocytic Leukemia 2008 criteria. Minimal residual disease was assessed by means of multicolor flow cytometry in bone marrow (sensitivity, 10
).
A total of 80 patients were treated. The median age was 65 years (range, 26 to 83). A total of 30% of the patients were 70 years of age or older. Overall, 92% of the patients had unmutated
,
aberration, or chromosome 11q deletion. With combined treatment, the proportions of patients who had complete remission (with or without normal blood count recovery) and remission with undetectable minimal residual disease increased over time. After 12 cycles of combined treatment, 88% of the patients had complete remission or complete remission with incomplete count recovery, and 61% had remission with undetectable minimal residual disease. Responses were noted in older adults and across all high-risk subgroups. Three patients had laboratory evidence of tumor lysis syndrome. The adverse-event profile was similar to what has been reported with ibrutinib and venetoclax.
In this study, combined venetoclax and ibrutinib was an effective oral regimen for high-risk and older patients with CLL. (Funded by AbbVie and others; ClinicalTrials.gov number, NCT02756897.).
Lenalidomide in follicular lymphoma Flowers, Christopher R; Leonard, John P; Fowler, Nathan H
Blood,
06/2020, Volume:
135, Issue:
24
Journal Article
Peer reviewed
Open access
Lenalidomide is an immunomodulatory drug approved in the United States for use with rituximab in patients with relapsed/refractory follicular lymphoma. We reviewed data from trials addressing the ...safety and efficacy of lenalidomide alone and in combination with rituximab as a first-line therapy and as a treatment of patients with relapsed/refractory follicular lymphoma. Lenalidomide-rituximab has been demonstrated to be an effective chemotherapy-free therapy that improves upon single-agent rituximab and may become an alternative to chemoimmunotherapy.
The two major subtypes of diffuse large B cell lymphoma (DLBCL)--activated B cell-like (ABC) and germinal center B cell-like (GCB)--arise by distinct mechanisms, with ABC selectively acquiring ...mutations that target the B cell receptor (BCR), fostering chronic active BCR signaling. The ABC subtype has a ∼40% cure rate with currently available therapies, which is worse than the rate for GCB DLBCL, and highlights the need for ABC subtype-specific treatment strategies. We hypothesized that ABC, but not GCB, DLBCL tumors would respond to ibrutinib, an inhibitor of BCR signaling. In a phase 1/2 clinical trial that involved 80 subjects with relapsed or refractory DLBCL, ibrutinib produced complete or partial responses in 37% (14/38) of those with ABC DLBCL, but in only 5% (1/20) of subjects with GCB DLBCL (P = 0.0106). ABC tumors with BCR mutations responded to ibrutinib frequently (5/9; 55.5%), especially those with concomitant myeloid differentiation primary response 88 (MYD88) mutations (4/5; 80%), a result that is consistent with in vitro cooperation between the BCR and MYD88 pathways. However, the highest number of responses occurred in ABC tumors that lacked BCR mutations (9/29; 31%), suggesting that oncogenic BCR signaling in ABC does not require BCR mutations and might be initiated by non-genetic mechanisms. These results support the selective development of ibrutinib for the treatment of ABC DLBCL.
Rituximab plus chemotherapy has been shown to be effective in patients with advanced-stage, previously untreated follicular lymphoma; nevertheless, most patients will have a relapse. Combination ...immunotherapy with lenalidomide and rituximab is an immunomodulatory regimen that has shown promising activity in patients with indolent B-cell non-Hodgkin's lymphoma.
We conducted this multicenter, international, phase 3 superiority trial to evaluate rituximab plus lenalidomide, as compared with rituximab plus chemotherapy, in patients with previously untreated follicular lymphoma. Patients were randomly assigned to receive one of the two regimens, followed by maintenance monotherapy with rituximab. Treatment with rituximab plus lenalidomide consisted of 18 cycles of the two drugs, followed by rituximab maintenance therapy every 8 weeks for 12 cycles (six additional doses). Treatment with rituximab plus chemotherapy consisted of the investigator's choice of one of three rituximab-based regimens, followed by maintenance monotherapy with rituximab every 8 weeks for 12 cycles. The primary end points were complete response (confirmed or unconfirmed) at 120 weeks and progression-free survival.
A total of 1030 patients were randomly assigned to receive rituximab plus lenalidomide (513 patients) or rituximab plus chemotherapy (517 patients). The rate of confirmed or unconfirmed complete response at 120 weeks was similar in the two groups: 48% (95% confidence interval CI, 44 to 53) in the rituximab-lenalidomide group and 53% (95% CI, 49 to 57) in the rituximab-chemotherapy group (P=0.13). The interim 3-year rate of progression-free survival was 77% (95% CI, 72 to 80) and 78% (95% CI, 74 to 82), respectively. A higher percentage of patients in the rituximab-chemotherapy group had grade 3 or 4 neutropenia (32% vs. 50%) and febrile neutropenia of any grade (2% vs. 7%), and a higher percentage of patients in the rituximab-lenalidomide group had grade 3 or 4 cutaneous reactions (7% vs. 1%).
Among patients with previously untreated follicular lymphoma, efficacy results were similar with rituximab plus lenalidomide and rituximab plus chemotherapy (with both regimens followed by rituximab maintenance therapy). The safety profile differed in the two groups. (Funded by Celgene; RELEVANCE ClinicalTrials.gov numbers, NCT01476787 and NCT01650701 , and EudraCT number, 2011-002792-42 .).
Follicular lymphoma is one of the most common non-Hodgkin's lymphomas. Although current frontline regimens are associated with high response rates, most patients still relapse. When progression is ...discovered, re-establishing the diagnosis and ruling out transformation in paramount. The outcomes following relapse have been improving due to the activity and increasing availability of novel agents with various mechanisms of action. Despite these advances, single agent activity is limited and the disease remains incurable in the majority of cases. Examples of drug classes with promising activity in relapsed disease include anti-CD20 monoclonal antibodies, immunomodulatory drugs (IMiDs), small molecule tyrosine kinase inhibitors, bcl2 inhibitors, epigenetic modifiers, conjugated antibodies, and checkpoint inhibitors. Many drugs in each class are associated with unique, variable and often surprising toxicity profiles. Combination studies are currently underway with novel-novel combinations and with traditional chemotherapy regimens. This overview will discuss the results of several recent studies exploring activity of novel drugs in relapsed follicular lymphoma.
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