34P - A Retrospective Analysis of Response to checkpoint inhibitors and its Correlation to both PD-L1 score and Tumor Mutation Burden in Patients with So...

Date 08 December 2017
Event ESMO Immuno-Oncology Congress 2017
Session Lunch & Poster Display session
Topics Renal Cell Cancer
Genitourinary Cancers
Surgical oncology
Therapy
Radiation oncology
Presenter Shayma Kazmi
Citation Annals of Oncology (2017) 28 (suppl_11): xi6-xi29. 10.1093/annonc/mdx711
Authors S.M. Kazmi
  • Oncology, Cancer Treatment Centers of America, 19124 - Philadelphia/US

Abstract

Background

Immunotherapy is used to treat multiple solid tumor malignancies but has a great response in a few. Challenges remain as to the best predictive test for response to checkpoint inhibitors. While PD-L1 expression has been the best correlative marker to date, others such as Tumor Mutation Burden and Tumor Infiltrating Lymphocytes are on the horizon as an adjunct. We studied patients with solid tumors who had both PD-L1 as well as TMB tested and we analyzed the group that received immunotherapy to assess correlation to response.

Methods

We analyzed a total of 110 patients of whom 45 patients had treatment response information available. Patients received either Pembrolizumab, Nivolumab or Atezolizumab. 27 of those patients had either a favorable or unfavorable response to these drugs. PD-L1 was classified as negative, low or high. TMB was categorized as low, intermediate or high per Foundation One. PD-L1 was measured by Neogenomics assay with anti-PD-L1 22C3 antibody. These data were collected as an extension to a previous study that found no correlation between PD-L1 expression and TMB values.

Results

When comparing TMB and PD-L1 between groups of pts with favorable and unfavorable response, TMB was significantly associated with response (p = 0.03, Wilcoxon rank sum test) and PD L1 was not (p = 0.06). Regression models suggested that TMB and PD L1 were significantly associated with response (p = 0.008 and p = 0.03 resp). Higher TMB and PD L1 were associated with better response. Age, gender, diagnosis and TMB class were not significant. PD L1 category was significantly associated with response (p = 0.002).

Conclusions

While our first study concluded that PD L1 and TMB are independent features of solid tumors, this study suggests that both tests may be needed to identify patient subsets that may benefit from immunotherapy. Higher TMB and PD-L1 levels were independently associated with better response to checkpoint inhibitors in solid tumor malignancies. Microsatellite instability and Tumor infiltrating lymphocytes are two additional predictive markers that need further exploration.

Clinical trial identification

Legal entity responsible for the study

Cancer Treatment Centers of America

Funding

None

Disclosure

All authors have declared no conflicts of interest.