Diffuse large B-cell lymphoma (DLBCL) is the most common form of non-Hodgkin lymphoma, rising in incidence among older populations. The standard of care for the approximate one-third of DLBCL patients who do not achieve remission with R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone) is salvage high-dose chemotherapy followed by consolidative autologous stem cell transplant, which leads to long-term disease-free survival for only 10-20 percent of relapsed/refractory patients. Patients who relapse within a year of initial therapy, those who relapse after transplant, and those who are ineligible for transplant due to age or comorbidities face the most significant unmet treatment need.
With an eye toward improving therapeutic options and outcomes for this patient population, the Lymphoma Program team, led by Dr. Jia Ruan, collaborated with colleagues nationwide and contributed significantly to a study examining the maximum tolerated dose and preliminary safety and activity of a novel three-drug combination – ibrutinib plus lenalidomide and rituximab – in treatment of relapsed/refractory DLBCL. The team’s encouraging findings were published in the American Society of Hematology’s Blood journal.
The study population consisted of 45 transplant-ineligible DLBCL patients whose disease returned after at least one prior therapy. Patients received oral ibrutinib daily, intravenous rituximab on every first day of six 28-day cycles, and oral lenalidomide on the first 21 days of each cycle. The treatment was provided as continuous chronic therapy in an outpatient clinic setting for as long as patients could derive benefit.
Forty-four percent of patients responded to the triplet, and 28 percent achieved a complete response. The combination performed particularly well (ORR: 65%, CR: 41%) in patients with non-germinal center b cell (non-GCB) DLBCL, a molecular subtype based on disease cell of origin that is not typically associated with favorable prognosis. Common treatment side effects included gastrointestinal complications, fatigue, myelosuppression (reduced blood cell production), hypokalemia (low blood potassium), peripheral edema and skin rash. Side effects could be monitored and mitigated by dose adjustment in the outpatient setting.
Dr. Jia Ruan
“This novel treatment consists of two oral agents typically used to treat B-cell lymphoma, plus the anti-CD20 antibody rituximab, and can be easily administered in the clinic or patient’s home,” said Dr. Jia Ruan. “This effective low-intensity approach makes it very appealing to a broad range of R/R DLBCL patients in need of treatment.”
With increasing knowledge of cancer biology and availability of new drugs, it is expected that therapy will be increasingly tailored to individual patients’ tumor subtypes. Examples of this in breast cancer, colon cancer and CML have emerged over the past ten years. Often referred to as “personalized medicine” or “precision medicine”, this targeted approach to cancer therapy relies on translational research that defines a drug’s clinical activity in the context of the tumor’s cellular and genomic pathology.
Translational research has characterized the molecular basis of the clinical heterogeneity in various lymphomas, and many new agents are in development for lymphoma. Although the targeted development of these drugs in specific lymphoma patient subgroups could potentially speed their availability to the right patients, there are two major challenges to targeted trials in lymphoma. First, the empiric clinical research has led to highly active drug combinations that improve outcomes for many patients with lymphoma and in some specific types current therapy does in fact successfully treat a portion of the patients; leaving fewer patients with an unmet medical need to enter clinical trials. Second, it is a practical challenge to test and quickly identify specific lymphoma patient subgroups that can be enrolled in clinical trials of targeted drugs. Therefore a personalized study should ideally use a practical, rapid test to identify a lymphoma group that is not responsive to known treatment and test a therapy that targets an important pathway in those tumors.
New Developments in Lymphoma 