Chronic lymphocytic leukemia (CLL) / Small lymphocytic leukemia (SSL)

Chronic lymphocytic leukemia (CLL) / Small lymphocytic leukemia (SSL) is one of the chronic lymphoproliferative disorders, which are a group of lymphoid neoplasms that affect the immune system.[9] It is a chronic lymphoproliferative disorder characterized by the progressive accumulation of functionally incompetent lymphocytes that are usually monoclonal in origin.[10]

Both CLL and SLL are classified as B-cell NHL and are characterized by the progressive accumulation of functionally incompetent lymphocytes that are usually monoclonal in origin.[11] CLL affects B-cells in the blood and bone marrow and SLL cancer cells are located in the lymph nodes and/or the spleen.[12]

Richter’s Transformation (RT) is a rare complication of CLL. It occurs in approximately 2-10% of all CLL patients and is characterized by the sudden transformation of the CLL into a significantly more aggressive form of large cell lymphoma.[13]

CLL/SLL is a type of mature B-cell neoplasm that is characterized by the accumulation of small, round lymphocytes in the peripheral blood, bone marrow, and lymphoid tissues. CLL/SLL usually follows an indolent course and is considered an incurable disease. Patients who develop relapsed or refractory disease and become resistant to new treatments have a poor prognosis and a high unmet medical need for new therapeutic options such as chimeric antigen receptor (CAR) T-cell therapy.12

With an estimated incidence of 4.7 new cases per 100,000 individuals, CLL/SLL are the most prevalent lymphoid malignancies and are the most common adult leukemia in the United States  and in Europe. In 2021, the number of newly diagnosed cases is projected to be 21,250, representing ~1.2% of all cancers in the US.[14]