PS1238 AUTOLOGOUS T CELLS MODIFIED BY CD30 & CD22 DUAL SPECIFIC CAR COMBINED SECRETION OF ANTI‐PDL1 SCFV IN TREATING PATIENTS WITH RELAPSED AND REFRACTORY HODGKIN LYMPHOMA
Authors: Li J. , Ho J. , Ma F. , Li Y. , Huang C. , Liu L. 
Published: June 2019

Background:

The efficacy of chimeric antigen receptor (CAR) modified T cells against CD30 (CAR30) in Hodgkin Lymphoma (HL) is limited by the suppressive tumor microenvironment (TME). Combined therapy of CAR30 with PD‐1/PD‐L1 MoAb may increase cure rates but remains to be proved. Boosting the in vivo expansion of infused CAR‐T cells and increasing cytokines release may also improve the clinical outcomes. In addition, eliminating B cells from TME may disrupt the essential interactions of tumor survival. We previously developed a CAR‐T cell product targeting on CD22, and simultaneously secreting an anti‐PDL1 ScFv construct (CAR22p). Preclinical data showed that CAR22p have stronger lytic activity and higher cytokines production when reacting with CD22+PDL1+ tumor line in comparison to CAR22.

Aims:

We conduct a pilot study (NCT03121625) to investigate the safety and efficacy of a dual transduced CAR‐T cell, both CAR30 and CAR22p, for r/r HL patients.

Methods:

The constructs of CAR30 and CAR22p are shown in Fig 1. CAR30 includes a truncated EGFR sequence, can be used to identify and select CAR positive cells. CAR22p includes a ScFv sequence derived from a MoAb against human PD‐L1. T cells stimulated by α‐CD3xCD28 beads are dual transduced with CAR30 and CAR22p. Transduced cells are expanded in serum free media formulation with IL‐2, −7 and −15. Percentages of CAR30+ and CAR22p+ T cells were determined by flow cytometry through staining with antibodies against EGFR and CD22‐Fc. Real‐time Q‐PCR using primers with specificity for the ScFvs of CAR30 and CAR22p can detect the in vivo CAR‐T persistence for either CAR. After lymphodepleting chemotherapy, products are infused at the protocol‐prescribed dose level.

Results:

Four subjects (ages 12–31 yr) with heavily pre‐treated cHL have been treated in this trial. All therapy was well tolerated. There were no grade 3 or 4 treatment‐related adverse events. The most common toxicities reported was fever in 3 patients (Pt), which were all controllable by anti‐infective and antipyretic intervention. At the 1 month assessment, all patients were found to have objective response. Pt#1 had history of CAR30 therapy after 17 rounds of chemotherapy and, who was enrolled following disease progression at 2 months after CAR30 infusion. Thereafter, she received 2nd infusion with 3e6/kg CAR30 and 1e6/kg CAR22p cells. At 1 month, she was assessed as stable disease (SD) by imaging criteria but notably had obviously reduction of pleural effusion. Pt#2 had 13 rounds of chemotherapy before infusion of 6e5/kg CAR30 and 2e5/kg CAR22p cells. She was assessed as SD at 1 month but had progressive disease at 6 months. She subsequently received a 2nd infusion of double doses of CAR30 and CAR22p, and achieved PR and remains until now (11 months post‐2nd infusion). Pt#3 achieved PR with a following time of 122 days. Of note, this patient had history of 18 cycles of PD‐1 therapy besides chemotherapy. Pt#4 was assessed as SD and remains with a following time of 100 days. In addition, the in vivo DNA levels and persistence for both CAR30 and CAR22p were analyzed by qPCR and FACS assay. All patients had detectable in vivo proliferation for either CARs.

Summary/Conclusion:

Preliminary data from the limited sample supports the safety and efficacy of cocktail CAR30 and CAR22p T cell in treating patients with r/r HL. Further study is required to understand the impact of CD22 targeting and PD‐L1 secretion on the improvement of efficacy. In parallel, we are designing a single bi‐specific CAR construct targeting on both CD30 and CD22 simultaneously combining anti‐PDL1 secretion.

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