Real-life efficacy and predictors of response to immunotherapy in pituitary tumors: a cohort study

OBJECTIVE

After temozolomide failure, no evidence-based treatment is available for pituitary carcinomas (PCs) and aggressive pituitary tumors (APTs). To date, only 12 cases treated with immune-checkpoint inhibitors (ICIs) have been published, showing encouraging efficacy. Predictive factors of response are lacking. Here, we aimed to assess the real-life efficacy and predictors of response to ICIs in PCs and APTs.

DESIGN AND METHODS

This study is a multicentric, retrospective, observational cohort study, including all PCs and APTs treated with ICIs in France up to March 2022. PD-L1 immunohistochemistry and CD8+ T cell infiltration were evaluated centrally.

RESULTS

Six PCs (four corticotroph and two lactotroph) and nine APTs (five corticotroph and four lactotroph) were included. The real-life efficacy of ICIs was lower than previously published data. Three corticotroph tumors (33.3%) showed partial response, one (11.1%) stable disease, while five (55.6%) progressed. One lactotroph tumor (16.7%) showed partial response, one (16.7%) stable disease, while four (66.7%) progressed. PCs responded far better than APTs, with 4/6 PCs showing partial response compared to 0/9 APTs. Corticotroph tumors responded slightly better than lactotroph tumors. In the four responsive corticotroph tumors, PD-L1 staining was negative and CD8+ T cell infiltration attained a maximum of 1% in the tumor center.

CONCLUSIONS

Confirmation of the presence or absence of metastases is necessary before starting ICIs. After temozolomide failure, ICIs appear as a good therapeutic option for PCs, especially for corticotroph carcinomas. Negative PD-L1 staining and very low CD8+ T cell infiltration in the tumor center should not preclude ICI administration in corticotroph carcinomas.

SIGNIFICANCE STATEMENT

This is the first study to assess the real-life efficacy of ICIs in pituitary carcinomas (PCs) and aggressive pituitary tumors. We also assessed potential predictors of response and are the first to assess the predictive value of CD8+ cell infiltration. We identified the tumor type as a major predictor, ICIs proving far more effective in treating PCs. Our study provides evidence that ICIs are a good option after temozolomide failure for PCs (four of six responded), especially for corticotroph carcinomas (three of four responded). We also provide evidence that negative PD-L1 staining and very low CD8+ cell infiltration in the tumor center should not preclude ICI administration in corticotroph carcinomas. Moreover, our findings point toward the need to systematically perform extension workup before starting ICIs.

Production of stable isotope labelled lipase Lip2 from Yarrowia lipolytica for NMR: investigation of several expression systems

Extracellular lipase Lip2 from Yarrowia lipolytica is a promising biocatalyst with unusual structural features, as indicated by X-ray crystallography. These features comprise a mobile domain called the lid that controls access to the catalytic site. Conformational rearrangements of the lid have been suggested to regulate lipase enzymatic activities. We used nuclear magnetic resonance to investigate the dynamics of Lip2 by exploring four expression systems, Escherichia coli, cell-free, Pichia pastoris and Y. lipolytica to produce uniformly labelled enzyme. The expression of Lip2 was assessed by determining its specific activity and measuring (15)N-(1)H HSQC spectra. Y. lipolytica turned out to be the most efficient expression system. Here, we report the first use of Y. lipolytica as an expression host for the production of uniform stable isotopic labelled protein for further structural and dynamics studies using NMR.

Zonal variations of types II, IX and XI collagen mRNAs in rat epiphyseal cartilage chondrocytes: quantitative evaluation of in situ hybridization by image analysis of radioautography

The spatial-temporal distribution of the mRNAs for type IX and type XI collagens were compared to that of type II collagen mRNA in the tibial epiphyseal plate cartilage of normal growing rats. The mRNAs were detected by in situ hybridization with radio-labelled specific probes and visualized by radioautography. The areas covered by the resulting silver grains were quantified by computer assisted image analysis. The areas in chondrocytes of each zone of the epiphyseal plate cartilage, which correspond to the stages of chondrocyte development and function were determined. Types II, IX and XI mRNAs were present to some extent in chondrocytes of all zones. The distributions of type II and type IX collagen mRNAs were similar with the highest concentrations in the proliferative zone, and the lowest in the resting and calcifying zones chondrocytes. In contrast, type XI collagen mRNA had a different distribution, with the lowest concentration in the resting zone chondrocytes and a significant decrease in the calcifying zone chondrocytes. These patterns correlates with the changes in chondrocyte function, and may reflect the roles of the type IX and type XI collagens. The data show that computer assisted image analysis of in situ hybridization radioautographic images is a precise, rapid tool for analysing differences in gene expression.