Which patients with diffuse large B cell lymphoma benefit most from CAR-T treatment?

This study compared the effectiveness of CAR-T treatment for patients with diffuse large B cell lymphoma (DLBCL). The authors found that while a significant number of all patients benefitted from the treatment, some patients were more likely to benefit from it than others.

During initial treatment for DLBCL, some patients do not respond (refractory) while cancer returns in other patients (relapsed). Patients with relapsed/refractory DLBCL require other treatment types. 

Chimeric antigen receptor T cells (CAR-T) is a recently developed therapy that has shown some success. In CAR-T, T cells, a type of immune cell, are taken from a patient and activated using CD28 or 4-1BB. They are also specifically targeted to cancer cells using molecules such as CD19 or CD20. It is unclear if the choice of activating molecule or targeting molecule affects the success of CAR-T treatment.

Data from 13 studies including 263 patients with relapsed/refractory DLBCL treated with CAR-T were analyzed.

Overall, 46.8% of patients achieved remission (no signs of cancer). 

T cells can be activated using the molecules CD28 or 4-1BB. Patients were 9% more likely to achieve remission with CD28 T cells. 52.5% of patients who used CD28 T cells achieved remission compared to 41.5% of patients who used 4-1BB T cells.

The molecules used to target T cells to the cancer cells can be CD19 or CD20. Patients were 5% more likely to achieve remission with CD19 than CD20. 49.2% of patients who used CD19 to target T cells achieved remission compared to 42.2% of patients who used CD20.

82.6% of patients who used CD19 experienced severe side effects compared with 33.3% of patients who used CD20.

Of the patients aged 65 or older, 45.4% achieved remission compared to 37% of patients under 65.  54.5% of patients aged 65 or older experienced severe side effects compared to 66.7% of patients under 65.

7 of 10 patients that received stem cell transplants achieved remission (70%). 8 of 28 patients that did not receive stem cell transplants achieved remission (28.6%).

The authors concluded that CAR-T is an effective treatment but may be more effective for patients who use CD28 T cells with the CD19 molecule.

The use of other studies for this analysis meant that some information, such as age, was not available for most studies. More data is needed to confirm these findings.