Complete Response in Metastatic Clear Cell Renal Cell Carcinoma Patients Treated with Immune-Checkpoint Inhibitors: Remission or Healing? How to Improve Patients' Outcomes?

Immunotherapy for renal cell carcinoma: New therapeutic combinations and adverse event management strategies: A review

Immune checkpoint inhibitor (ICI) combinations, as well as ICIs combined with tyrosine kinase inhibitors, have considerable potential for renal cell carcinoma (RCC) treatment. Newer targeted medications, gut microbiome, nanomedicines, and cyclin-dependent kinase (CDK) inhibitors demonstrate significant potential in preventing side effects and resistance associated with RCC treatment. Most patients, including those demonstrating long-term treatment effects, eventually demonstrate cancer progression. Nevertheless, recent studies have further revealed RCC pathogenesis and many acquired drug resistance mechanisms, which together have led to the identification of promising therapeutic targets. In addition to having roles in metabolism, immunogenicity, and the immune response to tumors, CDK4 and CDK6 regulate the cell cycle. Targeting CDK4 and CDK6, either separately or in combination with already approved treatments, may improve therapeutic outcomes in patients with kidney cancer. Other novel drugs, including pegylated interleukin 10, colony-stimulating factor 1 receptor inhibitors, CD40 agonists, and C-X-C receptor 4 inhibitors affect the tumor microenvironment and cancer cell metabolism. Moreover, a triple ICI combination has been noted to be efficacious. In general, compared with sunitinib as a single-drug treatment, newer ICI combinations improve overall survival in patients with RCC. Future research on the prevention of adverse events and medication resistance related to newer therapies may aid in ensuring effective treatment outcomes among patients with RCC. This article aims to summarize innovative immunotherapy drug combinations for RCC treatment and the mechanisms of action, drug resistance, and treatment of adverse events associated with these combinations.

[18F]FMISO-PET imaging reveals the role of hypoxia severity in checkpoint blockade response

CONTEXT

Hypoxia within the tumor microenvironment is a critical factor influencing the efficacy of immunotherapy, including immune checkpoint inhibition. Insufficient oxygen supply, characteristic of hypoxia, has been recognized as a central determinant in the progression of various cancers. The reemergence of evofosfamide, a hypoxia-activated prodrug, as a potential treatment strategy has sparked interest in addressing the role of hypoxia in immunotherapy response. This investigation sought to understand the kinetics and heterogeneity of tumor hypoxia and their implications in affecting responses to immunotherapeutic interventions with and without evofosfamide.

PURPOSE

This study aimed to investigate the influence of hypoxia on immune checkpoint inhibition, evofosfamide monotherapy, and their combination on colorectal cancer (CRC). Employing positron emission tomography (PET) imaging, we developed novel analytical methods to quantify and characterize tumor hypoxia severity and distribution.

PROCEDURES

Murine CRC models were longitudinally imaged with [18F]-fluoromisonidazole (FMISO)-PET to quantify tumor hypoxia during checkpoint blockade (anti-CTLA-4 + and anti-PD1 +/- evofosfamide). Metrics including maximum tumor [18F]FMISO uptake (FMISOmax) and mean tumor [18F]FMISO uptake (FMISOmean) were quantified and compared with normal muscle tissue (average muscle FMISO uptake (mAvg) and muscle standard deviation (mSD)). Histogram distributions were used to evaluate heterogeneity of tumor hypoxia.

FINDINGS

Severe hypoxia significantly impeded immunotherapy effectiveness consistent with an immunosuppressive microenvironment. Hypoxia-specific PET imaging revealed a striking degree of spatial heterogeneity in tumor hypoxia, with some regions exhibiting significantly more severe hypoxia than others. The study identified FMISOmax as a robust predictor of immunotherapy response, emphasizing the impact of localized severe hypoxia on tumor volume control during therapy. Interestingly, evofosfamide did not directly reduce hypoxia but markedly improved the response to immunotherapy, uncovering an alternative mechanism for its efficacy.

CONCLUSIONS

These results enhance our comprehension of the interplay between hypoxia and immune checkpoint inhibition within the tumor microenvironment, offering crucial insights for the development of personalized cancer treatment strategies. Non-invasive hypoxia quantification through molecular imaging evaluating hypoxia severity may be an effective tool in guiding treatment planning, predicting therapy response, and ultimately improving patient outcomes across diverse cancer types and tumor microenvironments. It sets the stage for the translation of these findings into clinical practice, facilitating the optimization of immunotherapy regimens by addressing tumor hypoxia and thereby enhancing the efficacy of cancer treatments.

SLC11A1 promotes kidney renal clear cell carcinoma (KIRC) progression by remodeling the tumor microenvironment

Kidney renal clear cell carcinoma (KIRC) is a highly immune-infiltrated kidney cancer with the highest mortality rate and the greatest potential for invasion and metastasis. Solute carrier family 11 member1 (SLC11A1) is a phagosomal membrane protein located in monocytes and plays a role in innate immunity, autoimmune diseases, and infection, but its expression and biological role in KIRC is still unknown. In this study, we sought to investigate the potential value of SLC11A1 according to tumor growth and immune response in KIRC. TIMER and UALCAN database was used to analyze the expression feature and prognostic significance of SLC11A1 and its correlation with immune-related biomarkers in KIRC. Proliferation, migration, and invasion were measured using colony formation, EdU, and transwell assays. Role of SLC11A1 on KIRC tumor growth was examined by the xenograft tumor model in vivo. Effects of KIRC cells on macrophage polarization and the proliferation and apoptosis of CD8+ T cells were analyzed using flow cytometry assays. Herein, SLC11A1 was highly expressed in KIRC tissues and cell lines. SLC11A1 downregulation repressed KIRC cell proliferation, migration, invasion, macrophage, and lymphocyte immunity in vitro, as well as hindered tumor growth in vivo. SLC11A1 is significantly correlated with immune cell infiltration and immune-related biomarkers. In KIRC patients, SLC11A1 is highly expressed and positively correlated with the immune-related factors CCL2 and PD-L1. SLC11A1 induced CCL2 and PD-L1 expression, thereby activating the JAK/STAT3 pathway. SLC11A1 deficiency constrained KIRC cell malignant phenotypes and immune response via regulating CCL2 and PD-L1-mediated JAK/STAT3 pathway, providing a promising therapeutic target for KIRC treatment.

Case report: Fatal overwhelming post-splenectomy infection in a patient with metastatic angiosarcoma treated with immunotherapy

A patient in his 40s with splenic angiosarcoma metastatic to the liver underwent splenectomy, chemotherapy, and partial hepatectomy before being treated on a clinical trial with CTLA4 and PD1 inhibitors. He had received pneumococcal and meningococcal vaccines post-splenectomy. On week 10, he developed grade 3 immune-related colitis, successfully treated with the anti-tumor necrosis factor-alpha inhibitor infliximab and steroids. After 4 cycles of treatment, scans showed partial response. He resumed anti-PD1 therapy, and 6 hours after the second dose of anti-PD1 he presented to the emergency room with hematemesis, hematochezia, hypotension, fever, and oxygen desaturation. Laboratory tests demonstrated acute renal failure and septicemia (Streptococcus pneumoniae). He died 12 hours after the anti-PD1 infusion from overwhelming post-splenectomy infection (OPSI). Autopsy demonstrated non-viable liver tumors among other findings. In conclusion, patients undergoing immunotherapy and with prior history of asplenia should be monitored closely for OPSI as they may be at increased risk.

CD70 is Consistently Expressed in Primary and Metastatic Clear Cell Renal Cell Carcinoma

BACKGROUND

CD70 is commonly overexpressed in renal cell carcinoma and is minimally expressed in normal human tissue, making it a potential therapeutic target for patients with advanced renal cell carcinoma. The expression frequency of CD70 in metastatic renal cell carcinoma is not well established.

MATERIALS AND METHODS

We assessed CD70 immunohistochemistry in 391 primary renal tumors and 72 metastatic renal cell carcinomas on a tissue microarray including 26 sets of paired primary and metastatic tumors.

RESULTS

CD70 was frequently overexpressed in clear cell carcinoma, with a significantly lower expression rate in papillary renal cell carcinoma (P < .0001). No expression of CD70 was detected in other types of renal tumors and normal renal parenchyma. In clear cell renal cell carcinoma, CD70 expression was significantly correlated with hypoxia pathway proteins, corroborating with a recent study suggesting that CD70 is a downstream target gene of hypoxia-inducible factor. While higher expression levels were observed in males and non-Caucasians, CD70 expression was not associated with tumor grade, sarcomatoid differentiation, stage, or cancer-specific survival. Further, analysis of 26 paired primary and metastatic tumors from same individuals revealed a concordance rate of 85%.

CONCLUSION

Our findings validated CD70 as a promising therapeutic target for patients with metastatic clear cell renal cell carcinoma. The utility of primary tumor tissue as surrogate samples for metastatic clear cell carcinoma awaits future CD70-targeted clinical trials.

Biological Biomarkers of Response and Resistance to Immune Checkpoint Inhibitors in Renal Cell Carcinoma

Renal cell carcinoma (RCC) represents around 2% of cancer-related deaths worldwide per year. RCC is an immunogenic malignancy, and treatment of metastatic RCC (mRCC) has greatly improved since the advent of the new immunotherapy agents, including immune checkpoint inhibitors (ICIs). However, it should be stressed that a large proportion of patients does not respond to these therapies. There is thus an urgent need to identify predictive biomarkers of efficacy or resistance associated with ICIs or ICI/Tyrosine kinase inhibitor (TKI) combinations; this is a major challenge to achieve precision medicine for mRCC in routine practice. To identify potential biomarkers, it is necessary to improve our knowledge on the biology of immune checkpoints. A lot of efforts have been made over the last decade in the field of immuno-oncology. We summarize here the main data obtained in this field when considering mRCC. As for clinical biomarkers, clinician and scientific experts of the domain are facing difficulties in identifying such molecular entities, probably due to the complexity of immuno-oncology and the constant adaptation of tumor cells to their changing environment.