The prognostic significance of PFS24 in follicular lymphoma following firstline immunotherapy: A combined analysis of 3 CALGB trials

Follicular lymphoma (FL) patients treated with firstline R‐CHOP who experience progression of disease (POD) within 2 years have a shorter survival than those who do not have POD within 2 years. Whether this observation holds for patients treated initially with biologic immunotherapy alone is unknown. We performed a retrospective analysis of 174 patients pooled from three frontline rituximab (R)‐based nonchemotherapy doublet trials: R‐galiximab (Anti‐CD80, CALGB 50402), R‐epratuzumab (Anti‐CD22, CALGB 50701), and R‐lenalidomide (CALGB 50803) to determine outcomes of early progressors and risk factors for early POD, defined as progression within 24 months from study entry. Twenty‐eight percent (48/174) of patients had early POD. After adjusting for the Follicular Lymphoma International Prognostic Index (FLIPI), patients with early POD from study entry had a worse OS compared with patients who did not progress within 2 years (HR = 4.33 (95% CI 1.50‐12.5), P = 0.007). For early POD, the 2‐year survival was 80% vs 99% for nonearly POD, and the 5‐year survival was 74% vs 90%, respectively. These findings suggest that the adverse survival of patients with early POD may be independent of initial treatment modality.

Current challenges in the management of follicular lymphoma

Although typically indolent in nature, follicular lymphoma remains an ongoing challenge for practicing oncologists. While response rates >90% can be achieved with rituximab-based chemoimmunotherapy in advanced stage patients, the complete remission rates are substantially lower and patients inevitably relapse. The inability to achieve a complete remission and an early progression of disease have recently been determined to be indicative of poorer long-term outcomes. A greater understanding of the pathogenesis of follicular lymphoma has enabled the development of targeted therapies, which may improve standard treatment approaches. Examples include lenalidomide and obinutuzumab, which are currently in front-line Phase III investigation. Other therapies of interest include small molecule inhibitors, immune checkpoint inhibitors and chimeric antigen receptor T cells.

Recommendations for Clinical Trial Development in Follicular Lymphoma

Follicular lymphoma (FL) is the second most common lymphoid malignancy, representing 20% to 25% of all cases of non-Hodgkin's lymphoma (NHL), and the most common of the indolent NHLs. FL is considered incurable in the majority of patients with the current standard therapeutic approaches, although outcomes have improved in the last few decades with our current therapies, with a median overall survival that now exceeds 18 years. While the majority of patients with FL have improved outcomes with our current therapeutic approaches, there are patients with high-risk disease features that have inferior outcomes to these therapies. There is an urgent need to integrate novel therapeutic agents into the treatment regimens for these patients to improve outcomes with continued evaluation of biomarkers indicative of prognosis and effects of these regimens on quality of life.

New drugs for follicular lymphoma

Despite the improvement in prognosis since the advent of rituximab, follicular lymphoma is still incurable and remains the cause of death of most afflicted patients. With the expanding knowledge of the pathogenesis of B-cell malignancies, in the last few years a plethora of new therapies acting through a variety of mechanisms have shown promising results. This review attempts to analyze the evidence available on these new drugs, which include new monoclonal antibodies and immunoconjugates, the anti-angiogenic and immunomodulatory agent lenalidomide, the proteasome inhibitor bortezomib, inhibitors of B-cell receptor pathway enzymes, such as ibrutinib, idelalisib, duvelisib and entospletinib, BCL2 inhibitors and checkpoint inhibitors. We conclude that despite the high expectations around the new therapeutic options for patients with refractory disease, these new drugs have side effects that require caution with their use, particularly in light of the still short follow up and the lack of both randomized trials and data on combination regimens.

A comprehensive review of lenalidomide in B-cell non-Hodgkin lymphoma

Lenalidomide, an immunomodulatory drug that the US Food and Drug Administration (FDA) approved for the treatment of multiple myeloma, 5q- myelodysplasia and mantle-cell lymphoma (MCL), has encouraging efficacy in other B-cell malignancies. Its unique mechanism of action is in part due to altering the tumor microenvironment and potentiating the activity of T and natural-killer (NK) cells. Impressive clinical activity and excellent tolerability allows broad applicability. Lenalidomide has been used in a wide range of B-cell malignancies for years, but in 2013, the FDA marked its approval as a single agent only in relapsed/refractory mantle-cell lymphoma. Perhaps most impressive is the efficacy of lenalidomide when combined with monoclonal antibodies. Impressive efficacy and toxicity profiles with the combination of lenalidomide and rituximab in B-cell lymphomas in both the upfront and relapsed/refractory setting may allow a shift in our current treatment paradigm in both indolent and aggressive non-Hodgkin lymphoma (NHL). This review will summarize the current data in the relapsed/refractory and front-line setting of NHL with single-agent lenalidomide as well as its use in combination with other agents.

Follicular lymphoma: first-line treatment without chemotherapy for follicular lymphoma

Opinion statement: The optimal initial treatment of follicular lymphoma (FL) is not known, and initial management of patients varies considerably between providers and institutions. The assertion that patients with low tumor burden can be observed for a period of time is being challenged owing to the safety and tolerability of novel therapeutics and the movement of the field away from traditional chemotherapy agents. Single agent rituximab has become increasingly popular as initial management of patients with low tumor burden disease, and there is evidence that prolonged treatment with rituximab can improve progression-free survival (PFS) when compared to induction with rituximab or observation. Radioimmunotherapy (RIT) has similarly shown efficacy in low tumor burden disease. Novel agents such as lenalidomide, idelalisib, and ibrutinib are being studied in the first-line setting. Importantly, none of these strategies have demonstrated an improved overall survival in a randomized study versus observation. It is the opinion of the authors that endpoints such as PFS alone, while important, should not drive changes in management with limited resources. Composite endpoints including quality of life are more informative on the true impact of treatments on patients with follicular lymphoma. Providers should encourage all patients to be treated in the context of an appropriate clinical trial when possible. If a patient is not a clinical trial candidate, we typically treat patients with advanced stage and high tumor burden with chemoimmunotherapy. The decision to give maintenance rituximab is individualized to the patient, as there is no overall survival benefit. In patients with early stage disease, we favor consideration of radiation therapy if the patient is a candidate. Our initial recommendation to patients with advanced stage, low tumor burden disease, is close observation or "watch and wait." We have observed that most patients become comfortable over time with an observation approach. If a patient is not comfortable with this recommendation, we will use single agent rituximab. If the patient responds to therapy, we do not recommend maintenance rituximab in low tumor burden disease but rather prefer a retreatment strategy or an extended schedule of four additional doses of rituximab.

Factors influencing outcome in advanced stage, low-grade follicular lymphoma treated at MD Anderson Cancer Center in the rituximab era

BACKGROUND

The optimal initial therapy of follicular lymphoma (FL) remains unclear. The aims of this study were to compare primary treatment strategies and assess the impact of maintenance rituximab and patterns of treatment failure.

PATIENTS AND METHODS

We retrospectively analyzed patients with treatment-naive advanced stage, grade 1-2 FL treated at our center from 2004 to 2014. We included 356 patients treated on clinical trials or standard of care with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP, n = 119); R-CHOP with maintenance (R-CHOP + M, n = 65); bendamustine/rituximab (BR, n = 45); BR with maintenance (BR + M, n = 35); R(2) (n = 94). We compared baseline characteristics, progression-free survival (PFS), overall survival (OS) and analyzed prognostic factors using univariate and multivariate analysis adjusted for treatment.

RESULTS

After a median follow-up of 4 years (range 0.2-15.0), the 3-year PFS was 60% [95% confidence interval (CI) 51% to 69%] for R-CHOP, 72% (59% to 82%) for R-CHOP + M, 63% (42% to 78%) for BR, 97% (80% to 100%) for BR + M and 87% (78% to 93%) for R(2). Patients treated with R-chemotherapy had more high-risk features than patients treated with R(2) but, by adjusted multivariate analysis, treatment with R(2) [hazard ratio (HR) 0.39 (0.17-0.89), P = 0.02] was associated with a superior PFS. Eastern Cooperative Oncology Group Performance status of one or more predicted inferior OS. Among patients treated with R-chemotherapy, maintenance was associated with the superior PFS [HR 0.38 (95% CI 0.21-0.68)]. By adjusted multivariate analysis, disease progression within 2 years [HR 5.1 (95% CI 1.57-16.83)] and histologic transformation (HT) [HR 11.05 (95% CI 2.84-42.93)] increased risk of death.

CONCLUSION

Induction therapy with R(2) may result in disease control which is comparable with R-chemotherapy. Early disease progression and HT are predictive of inferior survival.

Ibrutinib in B-cell Lymphomas

The standard frontline therapy for diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and mantle cell lymphoma (MCL) includes the use of chemoimmunotherapy and/or radiation therapy. When patients with these diseases relapse or are refractory to therapy, their diseases are considered incurable outside of the setting of an autologous or allogeneic stem cell transplant, which many patients are not candidates for due to age or comorbidities. The oral Bruton's tyrosine kinase (BTK) inhibitor, ibrutinib, targets the B-cell receptor (BCR) signaling pathway that is critical in the survival of these malignancies. It has shown promising activity in certain subtypes of DLBCL, in relapsed or refractory FL, and in relapsed or refractory MCL for which it has recently received FDA approval and should be considered for use in patients in first relapse. Ibrutinib is an oral therapy taken daily that has been well tolerated by patients. Given the high response rates, tolerability, and acceptable toxicities of ibrutinib therapy, it is now being evaluated in combination therapy both in relapsed B-cell malignancies and frontline studies in DLBCL and MCL. Several other promising agents targeting different kinases in the BCR signaling pathway also are currently under investigation.

Novel Pharmacotherapies for B-Cell Lymphomas and Leukemias

Novel pharmacotherapeutic agents were recently approved for treatment of low-grade B-cell neoplasms, and many other agents are under investigation. Several agents have demonstrated impressive activity in targeting malignant B-cell processes and specific pathways, all with the potential to expand our ability to effectively treat B-cell malignancies. The inhibitors of several cell regulatory proteins, including Bruton tyrosine kinase (Btk), phosphoinositide 3-kinase (PI3-K), B-cell lymphoma/leukemia-2 (Bcl-2), and histone deacetylases, as well as immunomodulatory agents are a few of the many pharmacotherapeutic agents under study. A comprehensive review and assessment is presented of the current pharmacotherapies under investigation targeting B-cell lymphomas and leukemias.