Interim analysis examining the feasibility of incorporating laser microdissection enrichment of tumor specimens and reverse phase protein array analysis with next generation sequencing into a molecular tumor board.

Abstract

e15068 Background: Since next generation sequencing (NGS) based profiling does not provide measures of protein abundance or activation state, clinical integration of reverse phase protein array (RPPA) with NGS could be useful for improving selection of targeted cancer therapy. We incorporated biopsy testing and proteogenomic analyses in an institutional Molecular Tumor Board (MTB) for cancer patients using CLIA-certified commercially available multi-omic platforms, including a commercially available CLIA RPPA functional protein drug target activation mapping platform. We present an interim analysis of our experience integrating functional phosphoprotein/protein based drug target activity data with NGS from 117 patients with metastatic solid tumors. Methods: Formalin-fixed, paraffin-embedded (FFPE) tumor biopsy specimens (n = 166) were obtained prospectively from patients as part of an IRB approved MTB. A representative H&E-stained tissue section for each specimen was reviewed by a board-certified surgical pathologist. Specimens with sufficient total tumor cellularity to achieve protein lysate input requirements for RPPA were thin sectioned onto laser microdissection (LMD) membrane slides for selective harvest of tumor epithelium by LMD and RPPA analysis. In parallel, specimens from each case were also submitted for NGS analysis. The multi-omic data for each patient was reviewed by a panel of clinicians and scientists as part of the Inova Institutional MTB for clinical decision-making. Results: Patient tissue specimens (median = 1 per patient; range 1-5) were reviewed to assess feasibility of enriching tumor areas via LMD prior to RPPA analysis. Specimens from 64/117 patients were used for LMD, RPPA, and NGS. 48/117 patients were dropped due to inadequate tumor cellularity, patient death, or referral cases with inadequate specimen. At this time, 7/117 patients remained in the consenting-LMD-RPPA workflow. The median time from patient consent to RPPA analysis completion was 47.4 days. During this period, specimens were outside of the standard hospital-NGS workflow (ie, utilized for sectioning and review for LMD-RPPA) for ~10 days (median). Integrated review of the RPPA and NGS data by the MTB supported a clinical recommendation change for 34/64 patients (53%) overall, with some dependency by primary disease site. Clinical trial information: U20-11-4308.Conclusions: Incorporation of RPPA analysis of LMD enriched tumor samples with NGS was feasible in this pan-cancer cohort, with the mean time to results being less than 7 weeks. RPPA data provided additional treatment considerations for 59% of patients, the outcomes for whom continue to be monitored. [Table: see text]