Immunotherapy with Low-Dose Subcutaneous Interleukin-2 plus Beta-Interferon as a Second-Line Therapy for Metastatic Colorectal Carcinoma

Aims and Background

Beta-interferon (β-IFN) has been proven to influence some IL-2-induced immune effects. On the basis of these experimental data, we evaluated the immunobiologic effects of an association between very low-dose IL-2 and β-IFN in advanced cancer patients.

Methods

The study was performed in 15 metastatic colon cancer patients, who progressed in response to a first-line chemotherapy with 5-FU plus folates. IL-2 was given subcutaneously at a daily dose of 3 million IU in the evening for 6 days/week for 4 weeks. β-IFN was injected subcutaneously at a dose of 3 million U/day for 7 days before the first IL-2 injection, then thrice/week until the end of IL-2 administration. In nonprogressed patients, a second cycle was given after a 14-day rest period.

Results

No objective tumor regression was seen. Stable disease was obtained only in 2/15 patients; the other 13 progressed. Toxicity was low in all cases. Natural killer cell and T-activated lymphocyte mean number significantly increased during the immunotherapy. Lymphocyte and eosinophil mean number also increased, without, however, significant differences. IL-2-induced suppressive events, consisting of an increase in T-suppressor cell number, and soluble IL-2 receptor levels were not blocked by β-IFN.

Conclusions

The study showed that the concomitant administration of β-IFN may determine an improvement in the immune performance in metastatic cancer patients treated with very low-dose IL-2, even though this biologic improvement does not seem to be associated to a control of tumor development. Further studies in patients with less advanced disease are needed to better define the impact of the immune improvement induced by low-dose IL-2 plus β-IFN on the clinical course of the neoplastic disease.

Abnormally enhanced blood concentrations of vascular endothelial growth factor (VEGF) in metastatic cancer patients and their relation to circulating dendritic cells, IL-12 and endothelin-1

Elevated VEGF blood concentrations have been proven to be associated with poor prognosis in human neoplasms. This finding is generally explained as a consequence of the potential angiogenic properties of VEGF itself. However, preliminary experimental studies suggest that VEGF, in addition to its angiogenic activity, may also play an immunosuppressant role by inhibiting dendritic cell (DC) maturation. The present study was performed to analyze blood levels of VEGF in cancer patients in relation to those of another potentially angiogenic tumor growth factor, endothelin-1 (ET-1), and to the absolute number of circulating immature and mature DC, and serum levels of the best known antitumor cytokine, IL-12. The study was performed in 100 healthy controls and in 80 solid tumor patients (colorectal cancer: 24; gastric cancer: 17; cancer of pancreas: 4; lung cancer: 13; breast cancer: 11; renal cell cancer: 6; gynecologic tumors: 5), 48 of whom showed distant organ metastases. In each patient, we have evaluated serum concentrations of VEGF-165, total VEGF, ET-1, IL-12 and the circulating number of immature (CD123+) and mature (CD11c+) DC. Mean serum levels of VEGF-165 were significantly higher in metastatic patients than in controls or in non-metastatic patients, whereas the total amounts of VEGF were not significantly higher. Moreover, it has been observed that patients with abnormally elevated blood concentrations of VEGF-165 showed significantly lower mean values of immature DC, mature DC and IL-12 and significantly higher mean levels of ET-1 than those with normal concentrations. This study, by confirming that advanced neoplastic disease may be associated with increased endogenous secretion of VEGF, seems to suggest that the association between high blood levels of VEGF and poor prognosis in cancer does not depend only on VEGF-induced stimulation of the neovascularization, but also on VEGF-related immunosuppression.

Surgery-induced decline in circulating dendritic cells in operable cancer patients: a possible explanation of postoperative immunosuppression

BACKGROUND/AIMS

The recent advances in the immunobiology of tumor have demonstrated the essential role of dendritic cells in anticancer immunity. Dendritic cells activate anticancer immunity by secreting interleukin-12 and by activating T helper lymphocytes, with the following production of interleukin-2. Since surgery-induced immunosuppression has been proven to be associated with a decline in the blood levels of both interleukin-2 and interleukin-12, it could depend at least in part on a transient deficiency of dendritic cells system. Unfortunately, at present there are no data about changes in circulating dendritic cell number during the postoperative period. This preliminary study was performed to evaluate the influence of surgery on dendritic cell number in the peripheral blood.

METHODOLOGY

The study included 14 consecutive operable gastrointestinal tract cancer patients, who were evaluated before and at day 7 of the postoperative period. The control group consisted of 50 healthy subjects. Immature (CD 123+) and mature (CD 11+) dendritic cell subsets were measured by FACS and monoclonal antibodies.

RESULTS

Cancer patients showed a significantly lower mean number of immature dendritic cells with respect to that found in controls. The mean number of mature dendritic cells was also lower in patients than in controls, without, however, significant differences. Finally, surgery induced a statistically significant decline in the mean number of both immature and mature dendritic cells, and the decrease was particularly pronounced for immature dendritic cells.

CONCLUSIONS

In addition to the well-demonstrated surgery-induced lymphocytopenia, this preliminary study shows that the surgical treatment may determine a significant decrease in circulating immature and mature dendritic cells. Because of the fundamental role of dendritic cells in regulating the immune responses, surgery-induced decline in circulating dendritic cells number could play a role in determining the immunosuppressive status, which characterizes the postoperative period.

Lymphocytosis Decline is not Responsible for Tumor Progression in Cancer Patients Chronically Treated with Interleukin-2

Aims and background

The antitumor activity of IL-2 is mediated by an increase in lymphocyte number. Moreover, our previous studies have shown that therapy for 1 week/month with low-dose subcutaneous IL-2 is sufficient to maintain high levels of lymphocytes in cancer patient who have had tumor regression or stable disease (SD) in response to IL-2 immunotherapeutic cycles. This study was performed to establish whether tumor progression in cancer patients chronically treated with IL-2 may be associated with lymphocyte number decline.

Methods

The study included 53 metastatic renal cell cancer patients, who were treated with 2 induction cycles of IL-2 subcutaneous immunotherapy (6 million IU/day for 5 days/week for 6 weeks, corresponding to one cycle). Tumor regression occurred in 15/53 patients, 20 patients had a SD, and the remaining 18 cases progressed. Non progressed patients (n = 35) underwent a maintenance therapy consisting of one week of therapy every month. After a median follow-up of 18 months, 26/35 patients with response or SD had progressed. The immune investigation consisted of lymphocyte, T lymphocyte, NK cell number determination and sCD25 level detection.

Results

The mean number of lymphocytes, T lymphocytes and NK cells observed on IL-2 maintenance therapy was significantly higher than that seen before beginning the immunotherapy. Moreover, mean number of lymphocytes and mean levels of sCD25 observed at the time of tumor progression were respectively lower and higher than those seen on maintenance therapy in the same patients, without, however, significant differences.

Conclusion

Despite the importance of lymphocytes in medianting the antitumor activity of IL-2, this study shows that tumor progression in cancer patients chronically treated with low-dose IL-2 after response or SD during IL-2 induction cycles is not associated with a significant decline in lymphocyte, T lymphocyte or NK cell numbers. Further studies, carried out to analyze the functional status of immune cells at the time of tumor progression, will be necessary to define the role of immunity in cancer patients progressing under IL-2 chronic therapy.

In vivo biological results of the association between interleukin-2 and interleukin-3 in the immunotherapy of cancer

The concomitant generation of macrophage-mediated suppressive events, as documented by the increase in neopterin and soluble interleukin-2 (IL-2) receptor (SIL-2R), and the enhanced production of cortisol, would represent the most investigated phenomena responsible for the reduced anticancer efficacy of IL-2 immunotherapy in humans. Based on our preliminary experimental studies suggesting a modulatory role of IL-3 on immune and endocrine effects induced by IL-2, a study was performed to evaluate the influence of IL-3 on biological effects of IL-2 cancer immunotherapy. We have evaluated 12 immunotherapeutic courses with IL-3 plus IL-2, which were performed in 6 patients with metastatic non-small cell lung cancer. The results were compared to those seen in 22 courses with IL-2 alone, carried out in 12 patients with metastatic non-small cell lung cancer. IL-3 was given intravenously at a daily dose of 1 microgram/kg/b.w. at 6 p.m. for 14 consecutive days, starting 7 days before IL-2. IL-2 was given subcutaneously at a dose of 3 million IU twice/daily for 5 days/week for 3 weeks. The increase in serum levels of the specific macrophage marker neopterin, induced by IL-2, was completely blocked by IL-3. The IL-2-induced SIL-2R rise was significantly lower during IL-3 plus IL-2 than under IL-2 alone. The increase in cortisol levels in response to IL-2 was neutralised by IL-3. The increase in lymphocyte, T lymphocyte, natural killer (NK) cell, activated T lymphocyte and eosinophil mean number was significantly higher during IL-3 plus IL-2 than during IL-2 alone. Episodes of fever, asthenia, anorexia, vomiting, anaemia and thrombocytopenia were significantly more frequent in patients receiving IL-2 alone than in those treated with IL-3 and IL-2. This preliminary study would suggest that IL-3 may improve the tolerability of IL-2 immunotherapy and enhance the biological antitumour properties of IL-2 by neutralising cortisol increase and macrophage-mediated suppressive events, with a following potential amplification of Il-2 anticancer efficacy.