160P - Real-world practices and physician perspectives on biomarker testing and treatment patterns in patients with locally advanced unresectable or metastatic (La/m) gastric/gastroesophageal junction (G/GEJ) adenocarcinoma in the US

Background

Human epidermal growth factor receptor 2 (HER2)-targeted therapy and immunotherapy have improved survival outcomes for patients with La/m G/GEJ adenocarcinoma. Biomarker testing for mismatch repair (MMR) or microsatellite instability (MSI), HER2, and programmed-death ligand 1 (PD-L1) is critical for determining appropriate therapy. We describe real-world data on testing and treatment patterns using the Adelphi Disease Specific Program (DSP).

Methods

Data was collected using the Adelphi’s DSP, a cross-sectional survey of US physicians taken between Sept 2022 and Feb 2023. Patients included those diagnosed with La/m G/GEJ adenocarcinoma on or after Jan 2021. Current biomarker testing treatment patterns, and physician attitudes were analyzed descriptively.

Results

Of the 438 pt records received from 60 treating physicians, 338 pts (77%) had La/m G/GEJ adenocarcinoma. Most pts had de novo (85%) disease, 71% were on first-line (1L) therapy and 29% on second line. Fluorouracil-based regimens were most common in 1L. MSI/MMR testing increased over time. Regardless of disease stage, almost all physicians (97%) reported biomarker testing at initial diagnosis to be “important” to “extremely important”. However, only a subset of patients had testing performed (Table): HER2 (69%), PD-L1 (51%), and MSI/MMR (44%); 18% had no biomarker testing. Table: 160P

Biomarker testing patterns

Conclusions

This study describes potential gaps in biomarker testing in real-world practice for pts with La/m G/GEJ adenocarcinoma. Despite most physicians reporting biomarker testing to be important at the time of diagnosis, only a subset of patients had testing reported. This outcome highlights a need to understand barriers to testing in clinical practice and to establish routine testing as standard of care.

Clinical trial identification

Editorial acknowledgement

Medical writing support was provided in accordance with the Good Publication Practice 2022 Update ( GPP 2022) and the International Committee of Medical Journal Editors (ICMJE) guidelines by George Pellegrino, MD, PhD, of Oxford PharmaGenesis Inc., Newtown, PA, USA, and was funded by Astellas Pharma, Inc.

Legal entity responsible for the study

This study, utilizing Adelphi Real World’s DSPTM was sponsored by Astellas Pharma, Inc. Data collection was undertaken by Adelphi Real World as part of an independent survey, entitled the “Adelphi Real World Advanced Gastric Cancer DSP.” The DSP is a wholly owned Adelphi Real World product. Astellas were one of multiple subscribers to the DSP.

Funding

This study, utilizing Adelphi Real World’s DSPTM was sponsored by Astellas Pharma, Inc. Data collection was undertaken by Adelphi Real World as part of an independent survey, entitled the “Adelphi Real World Advanced Gastric Cancer DSP.” The DSP is a wholly owned Adelphi Real World product. Astellas were one of multiple subscribers to the DSP.

Disclosure

K. Lewis, A. Lambert, G. Thomason: Financial Interests, Personal, Full or part-time Employment: Adelphi Real World. R. Fuldeore, S. Braun, K. Bernacki: Financial Interests, Personal, Full or part-time Employment: Astellas Pharma Global Development, Inc. G. Gourgioti: Financial Interests, Personal, Full or part-time Employment: Astellas Pharma Europe, Ltd. All other authors have declared no conflicts of interest.