Two randomised phase II trials of subcutaneous interleukin-2 and histamine dihydrochloride in patients with metastatic renal cell carcinoma

H2 antihistamines: May be useful for combination therapies in cancer?

Cancer morbimortality is still a great concern despite advances in research and therapies. Histamine and its receptors' ligands can modulate different biological responses according to the cell type and the receptor subtype involved. Besides the wide variety of histamine functions in normal tissues, diverse roles in the acquisition of hallmarks of cancer such as sustained proliferative signaling, resistance to cell death, angiogenesis, metastasis, altered immunity and modified microenvironment have been described. This review summarizes the present knowledge of the various roles of histamine H2 receptor (H2R) ligands in neoplasias. A bioinformatic analysis of human tumors showed dissimilar results in the expression of the H2R gene according to tumor type when comparing malignant versus normal tissues. As well, the relationship between patients' survival parameters and H2R gene expression levels also varied, signaling important divergences in the role of H2R in neoplastic progression in different cancer types. Revised experimental evidence showed multiple effects of H2R antihistamines on several of the cited hallmarks of cancer. Interventional and retrospective clinical studies evaluated different H2R antihistamines in cancer patients with two main adjuvant uses: improving antitumor efficacy (which includes regulation of immune response) and preventing toxic adverse effects produced by chemo or radiotherapy. While there is a long path to go, research on H2R antihistamines may provide new opportunities for developing more refined combination therapeutic strategies for certain cancer types to improve patients' survival and health-related quality of life.

Histamine in cancer immunology and immunotherapy. Current status and new perspectives

Cancer is the second leading cause of death globally and its incidence and mortality are rapidly increasing worldwide. The dynamic interaction of immune cells and tumor cells determines the clinical outcome of cancer. Immunotherapy comes to the forefront of cancer treatments, resulting in impressive and durable responses but only in a fraction of patients. Thus, understanding the characteristics and profiles of immune cells in the tumor microenvironment (TME) is a necessary step to move forward in the design of new immunomodulatory strategies that can boost the immune system to fight cancer. Histamine produces a complex and fine-tuned regulation of the phenotype and functions of the different immune cells, participating in multiple regulatory responses of the innate and adaptive immunity. Considering the important actions of histamine-producing immune cells in the TME, in this review we first address the most important immunomodulatory roles of histamine and histamine receptors in the context of cancer development and progression. In addition, this review highlights the current progress and foundational developments in the field of cancer immunotherapy in combination with histamine and pharmacological compounds targeting histamine receptors.

Novel immunotherapy combinations for genitourinary cancers

Introduction: Several immune checkpoint inhibitors are FDA-approved for metastatic/advanced RCC and urothelial carcinoma (UC) based on improvements in survival. The dendritic cell vaccine, sipuleucel-T, is also approved for patients with mCRPC, based on a 4-month survival benefit.Areas covered: Preclinical evidence suggests that there is promise in combining immune checkpoint inhibitors with several different classes of anti-cancer agents, including tumor-directed vaccines, cytokines, chemotherapy, and multi-targeted tyrosine kinase inhibitors. Here we review immunotherapy combinations currently approved for RCC, UC, and prostate cancer with a focus on emerging therapies. We conducted a search of peer-reviewed publications and recent meeting abstracts and provide an overview of ongoing combination immunotherapy trials for genitourinary malignancies and discussion of preliminary findings where available.Expert opinion: Recently, many potential immunotherapy combinations have emerged. In addition to determining clinical activity, important challenges include investigating additive adverse effects and determining the best sequence of therapy.

A randomized phase II trial of interleukin-2 and interferon-α plus bevacizumab versus interleukin-2 and interferon-α in metastatic renal-cell carcinoma (mRCC): results from the Danish Renal Cancer Group (DaRenCa) study-1

BACKGROUND

Interleukin-2 (IL2)-based immunotherapy is curative for a small subset of patients with metastatic renal-cell carcinoma (mRCC). Preclinical data suggests that bevacizumab (BEV), a humanized anti-VEGF monoclonal antibody, has potential immunomodulatory effects by permitting efficient natural killer (NK) cell-mediated killing and by reverting immune suppression.

PATIENT AND METHODS

We performed a randomized phase II study comparing IL2/IFN (interferon)/BEV with IL2/IFN in favourable/intermediate-risk mRCC patients. One hundred and eighteen patients received IFN 3 MIU subcutaneously (sc) daily and IL2 2.4 MIU/m² sc twice daily, 5 days per week for two consecutive weeks every 28-day-cycle, for 9 months; or supplemented with BEV 10 mg/kg, every 2 weeks intravenously (iv) until progression, unacceptable toxicity, or 1 year following no evidence of disease (NED). Primary end point was progression-free survival (PFS).

RESULTS

Baseline characteristics were well-balanced between the two arms; metastasis-free interval <1 year (75 versus 76%); prior nephrectomy (85 versus 86%); MSKCC favourable/intermediate-risk group (51/49 versus 52%/48%); three or more disease sites (41 versus 44%), respectively. The median PFS was 8.0 mo (95% CI, 4.2-11.9) with IL2/IFN/BEV and 8.1 mo (95% CI, 5.1-11.0) with IL2/IFN, p = .73. There was no difference in secondary endpoints, IL2/IFN/BEV versus IL2/IFN; median time-to-treatment failure (7.4 versus 5.6 mo, p = .54), response rate (44.1 versus 28.8%, p = .13), surgery of residual disease (17.0 versus 17.0%, p = 1.0), patients achieving NED (3.4 versus 8.5%, p = .44), and median overall survival (30.3 versus 34.1 mo, p = .39), respectively. TKI post progression was well-balanced (85 versus 78%). No new/unexpected toxicity was observed. Most common Grade 3/4 adverse events for IL2/IFN/BEV and IL2/IFN were fatigue (64 versus 61%), flu-like symptoms (37 versus 41%) and thrombosis (6.8 versus 18.6%, p = .01), respectively.

CONCLUSIONS

The addition of BEV to IL-2/IFN did not add efficacy in mRCC. (ClinicalTrials.gov, NCT01274273.).

WITHDRAWN: Immunotherapy for advanced renal cell cancer

This review is being updated and replaced following the publication of a new protocol (Unverzagt S, Moldenhauer I, Coppin C, Greco F, Seliger B. Immunotherapy for metastatic renal cell carcinoma [Protocol]. Cochrane Database of Systematic Reviews 2015, Issue 4. Art. No.: CD011673. DOI: 10.1002/14651858.CD011673). It will remain withdrawn when the new review is published.

The editorial group responsible for this previously published document have withdrawn it from publication.

Role of natural killer cell subsets and natural cytotoxicity receptors for the outcome of immunotherapy in acute myeloid leukemia

In a phase IV trial, 84 patients (age 18–79) with acute myeloid leukemia (AML) in first complete remission (CR) received cycles of immunotherapy with histamine dihydrochloride (HDC) and low-dose human recombinant interleukin 2 (IL-2) for 18 months to prevent leukemic relapse. During cycles, the treatment resulted in expansion of CD56^bright (CD3⁻/16⁻/56^bright) and CD16⁺ (CD3⁻/16⁺/56⁺) natural killer (NK) cells in the blood along with increased NK cell expression of the natural cytotoxicity receptors (NCRs) NKp30 and NKp46. Multivariate analyses correcting for age and risk group demonstrated that high CD56^bright NK cell counts and high expression of NKp30 or NKp46 on CD16⁺ NK cells independently predicted leukemia-free survival (LFS) and overall survival (OS). Our results suggest that the dynamics of NK cell subsets and their NCR expression may determine the efficiency of relapse-preventive immunotherapy in AML.

Evaluating surrogacy metrics and investigating approval decisions of progression-free survival (PFS) in metastatic renal cell cancer: a systematic review

BACKGROUND

In metastatic renal cell cancer (mRCC) trials, progression-free survival (PFS) is increasingly used instead of overall survival (OS) as the approval end point. Unlike other solid tumors, there is no published demonstration of what PFS is needed across and by treatment class in mRCC. We determine this and evaluate drug approval decisions in mRCC targeted therapy.

METHODS

We identified all randomized, controlled trials reporting PFS and OS in mRCC. Surrogacy metrics were the coefficient of determination and surrogate threshold effect (STE)-the PFS difference needed to predict, with 95% confidence, an OS difference. Data from regulatory commentaries, briefing documents and transcripts were extracted.

RESULTS

No exclusively chemotherapy trial met criteria. Of 30 qualifying trials, 11 trials (13 comparisons) used targeted therapy. The all-trials and immunotherapy-only trials analysis failed to demonstrate a STE. The targeted trials, using the more conservative regression analysis demonstrated an STE of 3.9 months and an R(2) of 0.44. Crossover upon progression, control to active treatment, was common. Regulatory approval, accelerated or regular, labeling, interim analyses, and adjudication were context specific.

CONCLUSIONS

A new targeted therapy trial showing a PFS difference of 3.9 months can claim an OS benefit in mRCC. PFS surrogacy for OS in metastatic renal cell is not generalizable across all drug classes.

Immunomonitoring and prognostic relevance of neutrophils in clinical trials

The clinical relevance of the interaction between human cancer and neutrophils has recently begun to emerge. This review will focus on recently published articles regarding immunomonitoring of neutrophils in blood and tumor tissue in clinical trials comprising the main human tumor types, with a strong emphasis on independent prognostic relevance assessed by multivariate analyses. The prognostic role of tumor-infiltrating neutrophils, elevated blood neutrophils and elevated blood neutrophil/lymphocyte ratio has been associated with poor clinical outcome in several human cancers, most notably in renal cell carcinoma, melanoma, colorectal cancer, hepatocellular carcinoma, cholangiocarcinoma, glioblastoma, GIST, gastric, esophageal, lung, ovarian and head and neck cancer. A striking finding is the notion that high baseline neutrophil count in either tumor or blood, or both, was identified as strong, independent risk factor for poor outcome in multivariate analyses, and the negative prognostic impact of neutrophils was not eliminated by increasing the dose of cytokines, chemotherapy, or targeted therapy. For several cancers, patients benefit most from therapy if baseline neutrophil was low. Thus, baseline neutrophils over-ride nadir counts in prognostic significance. In summary, a proportion of patients who do not experience benefit from surgery or medical intervention may be associated with a worst prognosis because they are characterized by baseline tumor-related neutrophilia protecting them from benefit from therapy. Further research to unraveling the cancer biology and new treatment options is encouraged.

Association between treatment effects on disease progression end points and overall survival in clinical studies of patients with metastatic renal cell carcinoma

BACKGROUND

The relationship between progression-free survival and time to progression (PFS/TTP) and overall survival (OS) has been demonstrated in a variety of solid tumours but not in metastatic renal cell carcinoma (mRCC).

METHODS

A systematic literature search was conducted to identify controlled trials of cytokine or targeted therapies for mRCC reporting information on treatment effects on PFS/TTP and OS for one or more comparison. The associations between treatment effects on PFS/TTP and OS were analysed using linear regression.

RESULTS

Thirty-one studies representing 10943 patients, 75 treatment groups, and 41 comparisons were identified. The correlation coefficient between the negative log of the hazard ratio (HR) for PFS/TTP (-ln HR(PFS/TTP)) vs the negative log of the HR for OS (-ln HR(OS)) was 0.80 (P<0.0001). In linear regression, the coefficient on -ln HR(PFS/TTP) vs -ln HR(OS) was 0.64 (95% confidence interval (CI): 0.470.81; R(2)=0.63), suggesting each 10% relative risk reduction (RRR) for PFS/TTP was associated with a 6% RRR for OS. A 1-month gain in median PFS/TTP was associated with a 1.17-month gain in median OS (95% CI: 0.59,1.76; R(2)=0.28).

CONCLUSION

In trials of treatments for mRCC, treatment effects on PFS/TTP are strongly associated with treatment effects on OS.

Histamine dihydrochloride for the treatment of acute myeloid leukemia, malignant melanoma and renal cell carcinoma

Histamine dihydrochloride is a vasoactive biogenic amine. It inhibits the reactive oxygen species formation in monocytes via histamine H2 receptors and protects natural killer and T cells from oxidative damage. Histamine has the potential to optimize cytokine-induced activation of T cells and natural killer cells; therefore, the addition of histamine to cytokine treatment may improve treatment efficacy. Clinical trials in solid tumors and in acute myeloid leukemia have demonstrated the potential to improve treatment outcome when histamine dihydrochloride is combined with immunotherapy. In patients with metastatic malignant melanoma, this strategy improved remission rates and increased survival. On the other hand, less promising results were reported for histamine dihydrochloride added to cytokines in patients with other solid tumors, especially in advanced renal cell carcinoma. A recent international Phase III trial performed in 320 patients showed that maintenance therapy with histamine dihydrochloride and IL-2 was able to improve leukemia-free survival in patients with acute myeloid leukemia, without an effect on overall survival. The combination of histamine dihydrochloride with IL-2 potentially offers an efficacious and tolerable maintenance strategy for patients with acute myeloid leukemia; however, its impact on survival remains to be explored.

Risk stratification and prognostication of renal cell carcinoma

OBJECTIVES

To review the most recent data on prognostic factors and describe the characteristics and prognostic accuracy of the most important prognostic systems available to predict the risk of recurrence, progression, and mortality in patients with renal cell carcinoma (RCC).

METHODS

The study was based on a non-systematic review of literature.

RESULTS

Clinical (performance status, and mode of presentation), anatomical (size and extension of the primary tumor, lymph node involvement, and distant metastasis), and histological factors (histological subtypes, nuclear grade, and tumor necrosis) are the most largely evaluated prognostic factors in RCC. Valuable prognostic accuracy has been shown for several laboratory parameters (erythrocyte sedimentation rate, platelet count, serum calcium, hemoglobin, and lactate dehydrogenase levels) and a few genetical and molecular markers (CAIX, B7-H1, and B7-H4). A few integrating systems have been proposed and validated, integrating both clinical and pathological (UCLA Integrating Staging Systems, Kattan nomogram, and Sorbellini nomogram) or only pathological variables (SSIGN score).

CONCLUSIONS

Several large and methodologically consistent studies have been published. The chance to integrate the data derived from each prognostic factor into prognostic algorithms and scores has allowed improving significantly the stratification of the prognosis of patients with RCC. The currently available prognostic systems can be further improved through the inclusion of molecular and genetic variables. Integrating prognostic systems should be used to design randomized controlled trials (RCTs), which will evaluate the efficacy of the new-targeted therapies in either neoadjuvant, adjuvant, or salvage treatments of patients with RCC.

Cervical squamous carcinoma cells are resistant to the combined action of tumor necrosis factor-alpha and histamine whereas normal keratinocytes undergo cytolysis

BACKGROUND

Previous reports showed that mast cells can typically be found in the peritumoral stroma of cervix carcinomas as well as in many other cancers. Both histamine and TNF-alpha are potent preformed mast cell mediators and they can act simultaneously after release from mast cells. Thus, the effect of TNF-alpha and histamine on cervical carcinoma cell lines was studied.

METHODS AND RESULTS

TNF-alpha alone induced slight growth inhibition and cell cycle arrest at G0/G1 phase in SiHa cells, but increased their migration. Histamine alone had no effect on cells. In addition, TNF-alpha and histamine in combination showed no additional effect over that by TNF-alpha alone, although SiHa cells were even pretreated with a protein synthesis inhibitor. Furthermore, TNF-alpha-sensitive ME-180 carcinoma cells were also resistant to the combination effect of TNF-alpha and histamine. In comparison, TNF-alpha or histamine alone induced growth inhibition in a non-cytolytic manner in normal keratinocytes, an effect that was further enhanced to cell cytolysis when both mediators acted in combination. Keratinocytes displayed strong TNF receptor (TNFR) I and II immunoreactivity, whereas SiHa and ME-180 cells did not. Furthermore, cervix carcinoma specimens revealed TNF-alpha immunoreactivity in peritumoral cells and carcinoma cells. However, the immunoreactivity of both TNFRs was less intense in carcinoma cells than that in epithelial cells in cervical specimens with non-specific inflammatory changes.

CONCLUSION

SiHa and ME-180 cells are resistant to the cytolytic effect of TNF-alpha and histamine whereas normal keratinocytes undergo cytolysis, possibly due to the smaller amount of TNFRs in SiHa and ME-180 cells. In the cervix carcinoma, the malignant cells may resist this endogenous cytolytic action and TNF-alpha could even enhance carcinoma cell migration.

Results of a multicenter randomized study to evaluate the safety and efficacy of combined immunotherapy with interleukin-2, interferon-{alpha}2b and histamine dihydrochloride versus dacarbazine in patients with stage IV melanoma

BACKGROUND

The safety and efficacy of immunotherapy with histamine dihydrochloride (HDC), interleukin-2 (IL-2) and interferon-alpha2b (IFN) compared with dacarbazine (DTIC) in adult patients with stage IV melanoma was evaluated.

PATIENTS AND METHODS

Two hundred and forty-one patients were randomized to either receive repeated 4-week cycles of IFN [3 MIU, s.c., once daily for 7 days], IL-2 (2.4 MIU/m(2), s.c., twice a day for 5 days) and HDC (1 mg, s.c., twice a day for 5 days) or DTIC 850 mg/m(2) i.v. every 3 weeks. The primary endpoint was overall survival.

RESULTS

Median survival was longer for patients receiving HDC/IL-2/IFN (271 days) than for patients receiving DTIC (231 days), but this did not achieve statistical significance. Four patients receiving HDC/IL-2/IFN and nine receiving DTIC experienced at least one grade 4 adverse event. Striking differences in overall survival were observed between countries participating in the study.

CONCLUSION

Treatment with HDC/IL-2/IFN was safely administered on an outpatient basis, but this immunotherapeutic regimen did not improve upon the response rate and overall survival seen with DTIC.

Impact of immune parameters on long-term survival in metastatic renal cell carcinoma

PURPOSE

The purpose of this study was to evaluate the impact of immunologic prognostic factors in combination with established clinical prognostic factors in patients with metastatic renal cell carcinoma (mRCC).

PATIENTS AND METHODS

A total of 120 consecutive patients with mRCC received interleukin-2 (IL-2) -based immunotherapy. Baseline tumor biopsies were available from 85 of these patients. Potential prognostic factors were analyzed by univariate and multivariate analyses.

RESULTS

Multivariate analysis (N = 120) identified high lactate dehydrogenase, lymph node metastases, low hemoglobin, low Karnofsky performance status, and bone metastases as independent poor prognostic clinical factors. The impact of these clinical factors has been demonstrated by others. Multivariate analysis (n = 85) also identified a high blood neutrophil count (> 6.0 x 10(9)/L; hazard ratio, 2.0; P = .015), the presence of intratumoral neutrophils (> 0 cells/mm2 tumor tissue; hazard ratio, 2.3; P = .001), and low intratumoral CD57+ natural killer cell count (< 50 cells/mm2 tumor tissue; hazard ratio, 2.1; P = .01) as independent poor prognostic immunologic factors. These three independent immunologic parameters had significant discriminatory power as supplemental risk factors in prognostic models based on the clinical risk factors, identifying subgroups within the favorable clinical group with estimated 5-year survival rates of 60%, 25%, and 0%, respectively. These findings were apparent in both our own prognostic model and in an extended Memorial Sloan-Kettering Cancer Center (New York, NY) prognostic model.

CONCLUSION

This study points on five clinical and three supplemental immunologic independent prognostic factors of survival in patients with mRCC receiving IL-2.

Monocytes and neutrophils as 'bad guys' for the outcome of interleukin-2 with and without histamine in metastatic renal cell carcinoma--results from a randomised phase II trial

Histamine (HDC) inhibits formation and release of phagocyte-derived reactive oxygen species, and thereby protects natural killer (NK) and T cells against oxidative damage. Thus, the addition of histamine may potentially improve the efficacy of interleukin-2 (IL-2). We have explored this potential mechanism clinically in two randomised phase II trials in metastatic renal cell carcinoma (mRCC). In parallel with the clinical trial in Denmark (n=63), we obtained serial blood samples and tumour biopsies searching for a potential histamine effect in situ. At baseline and on-treatment weeks 3 and 8, we monitored the ‘good guys’ (i.e. NK and T cells) and ‘bad guys’ (i.e. monocytes/macrophages and neutrophils) simultaneously in blood (n=59) and tumour tissue (n=44). Patients with high number of monocytes and neutrophils in peripheral blood had very poor survival, with apparently no benefit from either IL-2 alone or IL-2/HDC treatment. Blood monocytes (r=−0.36, P=0.01) and neutrophils (r=−0.46, P=0.001) were negatively correlated with cytotoxicity, whereas blood NK cells were positively correlated with cytotoxicity (r=0.39, P=0.002). Treatment with IL-2 alone resulted in a significantly higher number of circulating monocytes (P=0.037) and intratumoral macrophages (P=0.005) compared with baseline. In contrast, IL-2/HDC resulted in an unchanged number of circulating monocytes and intratumoral macrophages, and in addition, a significantly increased number of intratumoral CD56⁺ NK cells (P=0.008) and CD8⁺ T cells (P=0.019) compared with baseline. The study provides evidence that circulating monocytes and neutrophils are powerful negative prognostic factors for IL-2-based immunotherapy and establishes a biological rationale for the potential use of histamine in conjunction with IL-2 in mRCC.

Immunotherapy for advanced renal cell cancer

BACKGROUND

The course of advanced renal cell carcinoma is extremely variable, ranging from spontaneous remission to disease progression refractory to chemotherapy. Immunotherapy has held promise of improved outcomes based on uncontrolled studies and randomized controlled trials generally limited by small size and low power.

OBJECTIVES

To evaluate immunotherapy for advanced renal cell carcinoma by comparing: (1) high dose interleukin-2 to other options and (2) interferon-alfa to other options. The primary outcome of interest was overall survival at one year, with remission as the main secondary outcome of interest.

SEARCH STRATEGY

A systematic search of the CENTRAL, MEDLINE, and EMBASE databases was conducted for the period 1966 through end of December 2003. Handsearches were made of the proceedings of the periodic meetings of the American Urologic Association, the American Society of Clinical Oncology, ECCO - the European Cancer Conference, and the European Society of Medical Oncology for the period 1995 to June 2004.

SELECTION CRITERIA

Randomized controlled trials that selected (or stratified) patients with advanced renal cell carcinoma, utilized an immunotherapeutic agent in at least one study arm, and reported remission or survival by allocation. Fifty-three identified studies involving 6117 patients were eligible and all but one reported remission; 32 of these studies reported the one-year survival outcome.

DATA COLLECTION AND ANALYSIS

Two reviewers independently abstracted each article by following a prospectively designed protocol. Dichotomous outcomes for treatment remission (partial plus complete) and for deaths at one year were used for the main comparisons. Survival hazard ratios were also used for studies of interferon-alfa versus controls, and for two randomized studies of the value of initial nephrectomy prior to interferon-alfa in fit patients with metastases detected at the time of diagnosis.

MAIN RESULTS

Combined data for a variety of immunotherapies gave an overall chance of partial or complete remission of only 12.9% (99 study arms), compared to 2.5% in 10 non-immunotherapy control arms, and 4.3% in two placebo arms. Twenty-eight percent of these remissions were designated as complete (data from 45 studies). Median survival averaged 13.3 months (range by arm, 6 to 27+ months). The difference in remission rate between arms was poorly correlated with the difference in median survival so that remission rate is not a good surrogate or intermediate outcome for survival for advanced renal cancer. We were unable to identify any published randomized study of high-dose interleukin-2 versus a non-immunotherapy control, or of high-dose interleukin-2 versus interferon-alfa reporting survival. It has been established that reduced dose interleukin-2 given by intravenous bolus or by subcutaneous injection provides equivalent survival to high dose interleukin-2 with less toxicity. Results from four studies (644 patients) indicate that interferon-alfa is superior to controls (OR for death at one year = 0.56, 95% confidence interval 0.40 to 0.77). Using the method of Parmar 1998, the pooled overall hazard ratio for death was 0.74 (95% confidence interval 0.63 to 0.88). The weighted average median improvement in survival was 3.8 months. T he optimal dose and duration of interferon-alfa remains to be elucidated. The addition of a variety of enhancers, including lower dose intravenous or subcutaneous interleukin-2, has failed to improve survival compared to interferon-alfa alone. Two recent randomized studies have examined the role of initial nephrectomy prior to interferon-alfa therapy in highly selected fit patients with metastases at diagnosis and minimal symptoms: despite minimal improvement in the chance of remission, both studies of up-front nephrectomy improved median survival by 4.8 months over interferon-alfa alone. Recent studies have been examining anti-angiogenesis agents. A landmark study of bevacizumab, an anti-vascular endothelial growth factor antibody, was associated with significant prolongation of the time to progression of disease when given at high dose compared to low-dose or placebo therapy though frequency of remissions or survival were not improved.

AUTHORS' CONCLUSIONS

interferon-alfa provides a modest survival benefit compared to other commonly used treatments and should be considered for the control arm of future studies of systemic agents. In fit patients with metastases at diagnosis and minimal symptoms, nephrectomy followed by interferon-alfa gives the best survival strategy for fully validated therapies. The need for more effective specific therapy for this condition is apparent.