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Tianfu Zhang
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P2.04 - Immuno-oncology (ID 167)
- Event: WCLC 2019
- Type: Poster Viewing in the Exhibit Hall
- Track: Immuno-oncology
- Presentations: 1
- Now Available
- Moderators:
- Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall
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P2.04-17 - Immune Repertoire Is a Potential Predictive Biomarker for Evaluating the Efficacy of Mutant Neoantigen Specific T Cell Combined with PD1 Antibody (Now Available) (ID 555)
10:15 - 18:15 | Author(s): Tianfu Zhang
- Abstract
Background
The efficiency of PD1 monoclonal antibody used alone is not satisfactory. The therapeutic method of solid tumor with mutant neoantigen specific T (Nas-T) cell developed in this study is an adoptive cell therapy which is specific for each patient. Our previous research has proved that Nas-T can prolong patients' PFS with a good safety. We aim to further explore the effect of Nas-T on OS and to evaluate the characteristics of immune repertoire (IR) as a predictive biomarker.
Method
A total number of 12 patients with advanced solid tumors who failed after multiline treatments were recruited. They were treated with Nas-T cells, PD1 antibody and BSC; other 11 patients were treated with PD1 inhibitors and BSC as control. Peripheral blood was collected at baseline and per cycle (21-28d) respectively. Immunosequencing of the CDR3 regions of human TCRβ chains was used to detect IR. T-cell diversity and clonality for each IR was calculated. To quantitatively evaluate the consistency of the infused T-cell repertoires during the therapy, we adopted the Morisita overlap index (MOI), which considers the composition and the abundance of T-cell rearrangements. MOI ranges from 0 to 1, with 1 indicating identical TCR repertoires and 0 indicating completely distinct TCR repertoires between two samples.
Result
Updated data showed there was no statistical significance in OS (P>0.05), which may be related to the small sample size and short follow-up time. Compared to baseline, T-cell repertoire of NCB and DCB after 1st cycle displayed significant changes: Shannon 0.96 vs 1.20, P=0.004; Clonality 1.20 vs 0.64, P=0.003. Elevated Clonality may indicate expanded tumor-specific T-cells which could recognize mutant neoantigen specifically. MOI result for one patient, for example, exhibited a good consistency among each batch of infused Nas-T.
Conclusion
The combined immunotherapy of mutant Nas-T cell and PD1 antibody is more effective than PD1 antibody alone in prolonging PFS, but has no effect on OS. IR Clonality change shows its potential as a predictive biomarker.