Targeted Therapies for Follicular Lymphoma

Follicular lymphoma (FL) is the 2nd most common lymphoma in the USA/Western Europe. While incurable, the majority of patients are able to survive at least a decade with this disease. Response duration though varies, and subset of patients will relapse within 24 months of initial therapy (POD24). These patients have shortened survival compared to those who achieve more durable responses. Treatment interventions for patients are varied and include observation, radiation, or systemic therapies. Treatment outcomes have improved considerably over the last several decades with the introduction of new agents such as the CD 20 antibody rituximab and more recently with the advent of more targeted therapy. Most of the newer agents work differently from cytotoxic chemotherapy and either inhibit tumor-specific mutations, survival pathways, or harness the immune systems. While outcomes with traditional cytotoxic agents have been historically poor in certain subtypes such as POD24 and rituximab refractory disease, the reported outcomes with the newer agents have been encouraging as evident by several new drug approvals in FL. The biggest impact has been in the relapsed/refractory setting where we have approval of the immunomodulatory agent lenalidomide given in combination with rituximab. Based on the AUGMENT study, this agent has been approved for patients with R/R FL after one previous line of therapy. The EZH2 inhibitor, tazemetostat, was approved recently for patients with a known EZH2 mutation after one prior line of therapy or for FL patients who are deemed intolerant to other agents given the impressive safety profile in all patients. Finally, there is a plethora of agents that are designed to harness the immune system to combat this lymphoma. The data for these agents is still very early but nonetheless very impressive. In summary, FL is an incurable lymphoma without any standard of care options but has numerous treatments that have demonstrated some degree of efficacy. Recently we have made enormous strides in the understanding of some of the biological drivers of this disease which has allowed for refinement of treatment options. Moving forward, I would anticipate that we will continue to explore the use of agents that target specific mutations or utilize the immune system to hopefully one day achieve a cure.