# Clinical approach and utilizing liquid biopsies to interrogate suspected acquired resistance to PD-1 blockade

## TL;DR

The paper discusses how to clinically manage suspected resistance to PD-1 immunotherapy using liquid biopsies for better understanding and treatment decisions.

## Contribution

The paper introduces a multi-modal clinical guide for evaluating suspected acquired resistance to PD-1 blockade using liquid biopsies.

## Key findings

- Liquid biopsies offer real-time insights into treatment response and resistance mechanisms.
- Discrepancies between imaging, clinical status, and sequencing data should be carefully investigated.
- A systematic approach is needed to interrogate suspected resistance rather than assuming it.

## Abstract

PD-1 blockade is now routine for nearly all patients with non-small lung cancer. Acquired resistance to PD-1 blockade – defined generally as an initial response followed later by progression [1-3] is a common yet poorly understood concept. A key clinical challenge to insight has been a lack of standard guidance for clinical management of a case of suspected acquired resistance. The infrequency of performing tumor biopsies and the uncertainty of actionability from tissue sampling likely also contribute to limited insight into the biology of acquired resistance [4]. To address this knowledge gap and to highlight the value of tumor and liquid biopsy, we present a representative case of suspected acquired resistance to PD-1 blockade and propose a multi-modal guide for approaching this clinical scenario.

Acquired resistance to immunotherapy should not be assumed but should be thoroughly interrogated.

Liquid biopsies provide invaluable real-time insights into treatment response and should be utilized whenever possible.

Incongruity in imaging, clinical status, and sequencing should not be dismissed, and an alternative explanation for the discrepancy needs to be explored.