# Histology → first-line choice in mesothelioma

Source: https://onco.cc/pairings/histology-directs-first-line-meso/  
OnCo record `histology-directs-first-line-meso` (Pairing). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Read the tumour type under the microscope first: non-epithelioid tumours should get immunotherapy up front; epithelioid tumours can reasonably get either immunotherapy or chemo-immunotherapy.

## Summary

In mesothelioma the histological subtype read by histopathology and immunohistochemistry now directs the first-line choice, making this a diagnostic-therapeutic pairing. Sarcomatoid and biphasic tumours are chemoresistant but more immune-infiltrated, whereas epithelioid tumours retain sensitivity to pemetrexed-based chemotherapy. In pre-specified subgroups of CheckMate 743, nivolumab plus ipilimumab gave a large survival advantage over chemotherapy in non-epithelioid disease but only a small one in epithelioid disease, and pembrolizumab plus chemotherapy in IND.227 / KEYNOTE-483 and BEAT-meso showed the same pattern. Guidelines therefore favour immunotherapy up front for non-epithelioid tumours, while epithelioid tumours can receive either immunotherapy or chemo-immunotherapy.

## Fields

- Kind: Pairing
- Last checked: 2026-09-07
- Pairs: Histopathology & immunohistochemistry + Immune checkpoint inhibitors
- Type: diagnostic-therapeutic
- Rationale: Sarcomatoid tumours are chemoresistant but more immune-infiltrated; epithelioid tumours retain chemosensitivity.
- Evidence: Pre-specified subgroup analyses of two phase 3 trials plus BEAT-meso.

## Sources

- ClinicalTrials.gov NCT02899299: CheckMate 743: https://clinicaltrials.gov/study/NCT02899299
- ClinicalTrials.gov NCT02784171: IND.227 / KEYNOTE-483: https://clinicaltrials.gov/study/NCT02784171

## Connected records

- cancers: [Mesothelioma](https://onco.cc/cancers/mesothelioma/)
- drugs: [Ipilimumab](https://onco.cc/drugs/ipilimumab/), [Nivolumab](https://onco.cc/drugs/nivolumab/), [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/), [Pemetrexed](https://onco.cc/drugs/pemetrexed/)
- terms: [Epithelioid vs sarcomatoid (biphasic) mesothelioma](https://onco.cc/terms/epithelioid-vs-sarcomatoid/)
- trials: [CheckMate 743](https://onco.cc/trials/checkmate-743/), [IND.227 / KEYNOTE-483](https://onco.cc/trials/keynote-483/)
- technologies: [Histopathology & immunohistochemistry](https://onco.cc/technologies/histopathology-ihc/), [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/)

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