Interferons and interleukins in metastatic renal cell carcinoma

Short-course IL-15 given as a continuous infusion led to a massive expansion of effective NK cells: implications for combination therapy with antitumor antibodies

BACKGROUND

Full application of cytokines as oncoimmunotherapeutics requires identification of optimal regimens. Our initial effort with intravenous bolus recombinant human interleukin-15 (rhIL-15) was limited by postinfusional reactions. Subcutaneous injection and continuous intravenous infusion for 10 days (CIV-10) provided rhIL-15 with less toxicity with CIV-10 giving the best increases in CD8+ lymphocytes and natural killer (NK) cells. To ease rhIL-15 administration, we shortened time of infusion. Treatment with rhIL-15 at a dose of 3-5 µg/kg as a 5-day continuous intravenous infusion (CIV-5) had no dose-limiting toxicities while effector cell stimulation was comparable to the CIV-10 regimen.

METHODS

Eleven patients with metastatic cancers were treated with rhIL-15 CIV-5, 3 µg (n=4), 4 µg (n=3), and 5 µg/kg/day (n=4) in a phase I dose-escalation study (April 6, 2012).

RESULTS

Impressive expansions of NK cells were seen at all dose levels (mean 34-fold), including CD56bright NK cells (mean 144-fold for 4 µg/kg), as well as an increase in CD8+ T cells (mean 3.38-fold). At 5 µg/kg/day, there were no dose-limiting toxicities but pulmonary capillary leak and slower patient recovery. This led to our choice of the 4 µg/kg as CIV-5 dose for further testing. Cytolytic capacity of CD56bright and CD56dim NK cells was increased by interleukin-15 assayed by antibody-dependent cellular cytotoxicity (ADCC), natural cytotoxicity and natural killer group 2D-mediated cytotoxicity. The best response was stable disease.

CONCLUSIONS

IL-15 administered as CIV-5 substantially expanded NK cells with increased cytotoxic functions. Tumor-targeting monoclonal antibodies dependent on ADCC as their mechanism of action including alemtuzumab, obinutuzumab, avelumab, and mogamulizumab could benefit from those NK cell expansions and provide a promising therapeutic strategy.

TRIAL REGISTRATION NUMBERS

NCT01572493, NCT03759184, NCT03905135, NCT04185220 and NCT02689453.

IL15 by Continuous Intravenous Infusion to Adult Patients with Solid Tumors in a Phase I Trial Induced Dramatic NK-Cell Subset Expansion

PURPOSE

The first-in-human clinical trial with human bolus intravenous infusion IL15 (rhIL15) was limited by treatment-associated toxicity. Here, we report toxicity, immunomodulation, and clinical activity of rhIL15 administered as a 10-day continuous intravenous infusion (CIV) to patients with cancers in a phase I trial.

PATIENTS AND METHODS

Patients received treatment for 10 days with CIV rhIL15 in doses of 0.125, 0.25, 0.5, 1, 2, or 4 μg/kg/day. Correlative laboratory tests included IL15 pharmacokinetic (PK) analyses, and assessment of changes in lymphocyte subset numbers.

RESULTS

Twenty-seven patients were treated with rhIL15; 2 μg/kg/day was identified as the MTD. There were eight serious adverse events including two bleeding events, papilledema, uveitis, pneumonitis, duodenal erosions, and two deaths (one due to likely drug-related gastrointestinal ischemia). Evidence of antitumor effects was observed in several patients, but stable disease was the best response noted. Patients in the 2 μg/kg/day group had a 5.8-fold increase in number of circulating CD8⁺ T cells, 38-fold increase in total NK cells, and 358-fold increase in CD56^bright NK cells. Serum IL15 concentrations were markedly lower during the last 3 days of infusion.

CONCLUSIONS

This phase I trial identified the MTD for CIV rhIL15 and defined a treatment regimen that produced significant expansions of CD8⁺ T and NK effector cells in circulation and tumor deposits. This regimen has identified several biological features, including dramatic increases in numbers of NK cells, supporting trials of IL15 with anticancer mAbs to increase antibody-dependent cell-mediated cytotoxicity and anticancer efficacy.

Relevance of the immune system in human urological malignancies: prospective for future clinical treatments

The possible role of the immune system in resisting human malignancies has long been debated. Several recent findings from animal and human studies have restimulated interest in the immune surveillance hypothesis for tumor control. These findings have been complied from various disciplines including cytokine therapy, adoptive immunotherapy, and gene therapy. Following the initial euphoria, it is now clear that immunotherapy of selected cancer cases in the early stages of tumor development may make an important contribution to tumor control, particularly in dealing with minimal residual disease after tumor debulking. This review discusses some of these issues and proposes approaches that could pave the way for better selection of the patients best suited for immunotherapy. We would argue that therapies directed at the re-expression of major histocompatibility complex (MHC) class I antigens might improve outcomes in immune-therapy-based treatments.

Assessment of proliferating cell nuclear antigen expression and prognosis in patients with renal cell carcinoma with pulmonary metastases

BACKGROUND

The presence of proliferating cell nuclear antigen (PCNA) has been suggested as a more important prognostic marker than either grade or mitotic index in the prognosis of patients with renal cell carcinoma. We assessed the immunoreactivity of PCNA in primary lesions and pulmonary metastases from patients with renal cell carcinoma and correlated the results with various histopathologic features and prognostic factors.

METHODS

We studied the relationship between PCNA expression and clinical prognostic factors from resected primary lesions and pulmonary metastases from 10 patients and primary lesions from 32 patients with renal cell carcinoma without metastases. The cells were immunohistochemically stained with PCNA monoclonal antibody (PC-10) and 1000 nuclei were counted. The results were expressed as a ratio of stained to total cells (PCNA labeling index, LI %).

RESULTS

The PCNA LI of pulmonary metastatic nuclei was significantly higher than the PCNA LI of renal lesions either from patients with (P < 0.05) or without (P < 0.01) metastases. Also, the mean PCNA LI of the pulmonary lesions in patients dying within 3 years of diagnosis was higher than the mean PCNA LI of patients surviving greater than 3 years.

CONCLUSION

Our findings suggest that the PCNA LI, which was determined by immunohistochemical analysis, is an important marker reflecting the biologic behavior of renal cell carcinomas. The degree of PCNA expression in this study was of prognostic significance.

Natural history and therapy of metastatic renal cell carcinoma: the role of interleukin-2

BACKGROUND

Despite significant advances in understanding the biology of renal cell carcinoma (RCC) during the past decade, metastatic disease remains nearly incurable and a major medical challenge. Because RCC is known to be immunogenic, immunotherapeutic agents such as recombinant human interleukin-2 (rIL-2) and interferon-alpha (IFN-alpha) have represented encouraging treatment modalities.

METHODS

A review of the natural history of and therapeutic approaches to RCC was examined. Studies involving rIL-2 alone and in combination with other adjuvant therapies were critically evaluated.

RESULTS

Overall response rates for metastatic RCC patients treated with rIL-2 were similar (i.e., in the range of 15-20%), regardless of whether rIL-2 was administered as monotherapy or in combination with IFN-alpha. Recombinant IL-2 monotherapy response rates were similar to those of IFN-alpha, but with an increased frequency of complete responses and enhanced response duration. Subcutaneous administration generally resulted in lower toxicity than intravenous administration. The roles of chemotherapy or adoptive immunotherapy in combination with rIL-2 and IFN-alpha therapy remain unclear and require further study. The importance of patient performance status as a predictor of response and survival in rIL-2 therapy was demonstrated.

CONCLUSIONS

The use of rIL-2 with or without IFN-alpha may represent the most useful therapeutic approach currently available for patients with good performance status. In patients with borderline performance status or severe comorbid disease, therapeutic approaches depend on patient factors and outcome expectation and may involve cytokine therapy. However, regardless of performance status, palliative measures and/or observation are important choices, because the majority of patients with metastatic RCC are incurable.