1055P - Safety and Activity of SmarT cells plus PD-1 blocking antibodies in patients with heavily pretreated solid cancers: An open-label and dose-escalation study

Background

Efficient infiltration of activated T cells into tumors plays an important role in the therapeutic effect of adoptive cell immunotherapy. We previously modified T cells with a tumor-penetrating peptide iRGD (SmarT cells), and demonstrated that SmarT cells promote tumor-specific lymphocyte infiltration and enhanced the antitumor efficacy of PD-1 blocking strategy.

Methods

Here we report the interim analysis results of an ongoing phase 1/2 dose-escalation clinical trial of SmarT plus PD-1 mAb in patients with previously treated solid cancers (ChiCTR2200061306). The primary objective was safety for the combination of SmarT cells, low dose radiation and PD-1 mAb; secondary objectives included efficacy and dose-finding of SmarT cells. We treated 10 patients with three SmarT doses: 1.0 × 10⁹, 5.0 × 10⁹ or 1.0 × 10⁹ cells. The low dose radiation (1Gy) was carried out 24 hours before SmarT injection.

Results

Three patients experienced a grade 2 fever. Two patients experienced a grade anemia. No cytokine release syndrome (CRS) occurred. No grade 3 or higher treatment-related adverse events or deaths were reported. A total of three patients had stable disease (SD) and seven patients had a progressive disease (PD). The disease control rate (DCR) reached 30.0%. The median progressive free survival time (mPFS) was 71 days and the median overall survival time (mOS) was 201 days.

Conclusions

These initial results suggest that SmarT cells has promising efficacy with an acceptable safety profile in patients with heavily pretreated, solid cancers.

Clinical trial identification

The trial protocol number is ChiCTR2200061306 and the release date 20 June 2022.

Editorial acknowledgement

Legal entity responsible for the study

The Ethics Committee of Nanjing Drum Tower Hospital.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.