Clinical significance of the loss of CD20 antigen on tumor cells in patients with relapsed or refractory follicular lymphoma

Retrospective Study of CD20 Expression Loss in Relapsed or Refractory B-Cell Non-Hodgkin Lymphoma

Background

CD20-targeted therapies are widely used in the management of B-cell lymphomas. Re-treatment with CD20-directed agents is common; however, previous research has demonstrated loss of CD20 expression at relapse in a subset of patients.

Methods

In this single-center retrospective cohort of 243 patients, CD20 analysis was performed by immunohistochemistry (IHC) and/or flow cytometry at diagnosis and at relapse if a biopsy was performed.

Results

Of 109 patients with relapsed or refractory B-cell lymphoma, 59 patients with CD20-positive lymphoma at diagnosis underwent a biopsy at relapse for a total of 76 biopsies across all relapses. The rate of partial or complete CD20 expression loss was 11.9% (four patients with partial loss, three patients with complete loss). There were four cases of CD20 loss at first relapse (three IHC, one flow cytometry), two at second relapse (one IHC, one IHC and flow cytometry), and one at fifth relapse (IHC and flow cytometry). CD20 antigen escape was observed in marginal zone lymphoma, follicular lymphoma, and diffuse large B-cell lymphoma (DLBCL). All patients with CD20 expression loss previously received rituximab. Among patients with CD20 antigen escape, 85.7% had stage IV disease, and median overall survival after CD20 loss was 4 months. In the group of five patients with indolent lymphoma and CD20 expression loss, three patients (60%) had concurrent transformation to high-grade lymphoma.

Conclusions

This study, which reinforces the importance of repeating a biopsy at relapse before implementing CD20-directed therapy, is particularly relevant given the widespread use of rituximab along with the emerging significance of CD20-targeted bispecific antibodies in the management of B-cell lymphomas.

Case Report: CD19 CAR T-cell therapy following autologous stem cell transplantation: a successful treatment for R/R CD20-negative transformed follicular lymphoma with TP53 mutation

Background

Follicular lymphoma (FL), a common indolent B-cell lymphoma, has the potential to transform into an aggressive lymphoma, such as diffuse large B-cell lymphoma (DLBCL). The outcome of patients with transformed follicular lymphoma (tFL) is poor, especially in patients with transformed lymphoma after chemotherapy and patients with progression within 24 months (POD24). Chimeric antigen receptor (CAR) T-cell therapy combined with autologous stem cell transplantation (ASCT) has promising antitumor efficacy.

Case presentation

Here, we described a 39-year-old male patient who was initially diagnosed with FL that transformed into DLBCL with POD24, CD20 negativity, TP53 mutation, and a bulky mass after 3 lines of therapy, all of which were adverse prognostic factors. We applied a combination approach: CD19 CAR T-cell infusion following ASCT. Ibrutinib was administered continuously to enhance efficacy, DHAP was administered as a salvage chemotherapy, and ICE was administered as a bridging regimen. The patient underwent BEAM conditioning on days -7~ -1, a total of 3.8 × 106/kg CD34+ stem cells were infused on days 01~02, and a total of 108 CAR T cells (relmacabtagene autoleucel, relma-cel, JWCAR029) were infused on day 03. The patient experienced grade 2 cytokine release syndrome (CRS), manifesting as fever and hypotension according to institutional standards. There was no immune effector cell-associated neurotoxicity syndrome (ICANS) after CAR T-cell infusion. Finally, the patient achieved CMR at +1 month, which has been maintained without any other adverse effects.

Conclusion

This case highlights the amazing efficacy of CD19 CAR T-cell therapy following ASCT for R/R tFL, thus providing new insight on therapeutic strategies for the future.