Study Proposes Using RT Bridging Therapy Before CAR-T Therapy for R/R LBCL

Radiotherapy (RT) is an effective bridging option for disease control in high-risk patients with relapsed or refractory large B-cell lymphoma (LBCL) who are preparing to receive CAR T-cell therapy, study findings show (Blood Adv. 2020;4[13]:2871-2883).

“The impact of bridging therapy (BT) administered between leukapheresis and [CAR] T-cell therapy for [LBCL] is unclear,” wrote Chelsea C. Pinnix, MD, PhD, Department of Radiation Oncology and Division of Radiation Oncology, MD Anderson Cancer Center, Houston, Texas, and colleagues.

In a pool of 148 patients with LBCL who underwent leukapheresis for planned axicabtagene ciloleucel (axi-cel) infusion, Dr Pinnix et al assessed the influence that BT (systemic therapy [ST], RT, or combined-modality therapy [CMT]) has on outcomes.

The 81 (55%) patients given BT were more likely to have international prognostic index (IPI) scores ≥3 (P ≤.01), bulky disease (P = .01), and elevated lactate dehydrogenase (LDH; P ≤.01) than those who were not.

The 1-year rates of progression-free (PFS) and overall survival (OS) were 40% and 65% in patients not given BT (P = .01) vs 21% and 48% in patients given BT (P = .05), respectively.

A total of 24 (16%) patients did not receive axi-cel, primarily due to lymphoma progression (88%), despite 80% (n = 19) receiving BT; among 124 patients given axi-cel, 62 (50%) received BT with ST (n = 45), RT (n = 11), or CMT (n = 6).

Of note, the 1-year PFS and OS rates were not significantly different between recipients and nonrecipients of BT (P = .06 and .21, respectively).

In the ST, RT, and CMT groups, there was no difference in proportion of patients with IPI ≥3, limited-stage disease, or elevated LDH.

Of note, patients given ST bridge therapy had an inferior 1-year PFS compared with non-BT patients (P = .01), and RT-bridged patients had a PFS improved compared with that of ST-bridged patients (P = .05).

“Despite the poor prognosis associated with requiring BT, RT can be an effective bridging strategy,” Dr Pinnix and co-investigators concluded.

“Future studies are necessary to identify strategies that may improve access to CAR T-cell therapy and outcomes,” they added.—Hina M. Porcelli