Phase II trial of recombinant alpha-2b-interferon and low-dose cyclophosphamide in advanced melanoma and renal cell carcinoma

What is the role of chemotherapy in the treatment of melanoma?

The approval of ipilimumab and inhibitors of the BRAF pathway for the treatment of melanoma has provided multiple therapeutic options for patients. Although these new agents improve survival compared with chemotherapy alone, the majority of patients will progress and will receive chemotherapy at some point in the course of their disease. Whether the clinical efficacy of chemotherapy can be improved by targeting resistance mechanisms is an area of active investigation. In addition, chemotherapy may be of use modulating the efficacy of the newer agents.

Metastatic melanoma patients treated with dendritic cell vaccination, Interleukin-2 and metronomic cyclophosphamide: results from a phase II trial

Dendritic cells (DC) are the most potent antigen presenting cells and have proven effective in stimulation of specific immune responses in vivo. Competing immune inhibition could limit the clinical efficacy of DC vaccination. In this phase II trial, metronomic Cyclophosphamide and a Cox-2 inhibitor have been added to a DC vaccine with the intend to dampen immunosuppressive mechanisms. Twenty-eight patients with progressive metastatic melanoma were treated with autologous DCs pulsed with survivin, hTERT, and p53-derived peptides (HLA-A2(+)) or tumor lysate (HLA-A2(-)). Concomitantly the patients were treated with IL-2, Cyclophosphamide, and Celecoxib. The treatment was safe and tolerable. Sixteen patients (57 %) achieved stable disease (SD) at 1st evaluation and 8 patients had prolonged SD (7-13.7 months). The median OS was 9.4 months. Patients with SD had an OS of 10.5 months while patients with progressive disease (PD) had an OS of 6.0 months (p = 0.048) even though there were no differences in prognostic factors between the two groups. Despite the use of metronomic Cyclophosphamide, regulatory T cells did not decrease during treatment. Indirect IFN-γ ELISPOT assays showed a general increase in immune responses from baseline to the time of 4th vaccination. Induction of antigen-specific immune responses was seen in 9 out of 15 screened HLA-A2(+) patients. In conclusion, the number of patients obtaining SD more than doubled and 6-month survival significantly increased compared to a previous trial without Cyclophosphamide and Celecoxib. A general increase in immune responses against the tested peptides was observed.

Novel treatments for metastatic renal cell carcinoma

The mainstay of any curative treatment in renal cell carcinoma (RCC) is surgery. In case of metastatic disease at presentation a radical nephrectomy is recommended to good performance status patients prior to start of interferon-alfa treatment. Interferon-alpha (IFN-alpha) offers in a small but significant percentage of patients advantage in overall survival; interleukin-2 (IL-2) based therapy gives similar survival rates. To date hormonal and chemotherapy do not have a proven impact on survival. The recent new insights in the molecular biology of clear RCC has revealed a key-role for vascular endothelial growth factor (VEGF) in the stimulation of angiogenesis in this highly vascularized tumour. This opens interesting new treatment strategies including: blockage of VEGF with the monoclonal antibody bevacizumab and inhibition of VEGF receptor tyrosine kinases (with small oral molecules such as SU11248 or PTK787). Likewise, inhibition of the Raf kinase pathway (with oral Bay 43-9006) or inhibition of the mTOR pathway (with i.v. CCI-779) are under investigation. Preliminary clinical results with all these compounds are interesting and the results of ongoing phase III studies will become available in the next years.

Potential of interferon-alpha in solid tumours: part 1

Interferon-alpha (IFNalpha) is a pleiotropic cytokine with direct and indirect antitumour effects. These include prolongation of the cell cycle time of malignant cells, inhibition of biosynthetic enzymes and apoptosis, interaction with other cytokines, and immunomodulatory and antiangiogenic effects. The first clinical trials in solid tumours used crude preparations of natural IFNalpha and demonstrated that tumour regressions in solid tumours and haematological malignancies were possible. Since the advent of genetic engineering technology, recombinant (r) IFNalpha has been widely evaluated in solid tumours. This review discusses the use and potential of rIFNalpha in solid tumours; the first part focuses on malignant melanoma and metastatic renal cell carcinoma (RCC). In the adjuvant treatment of malignant melanoma, rIFNalpha has been tested in randomised trials in more than 6000 patients. High-dosage IFNalpha (> or =10MU) prolongs disease-free survival (DFS) but not overall survival (OS). Low-dosage IFNalpha (< or =3MU) has not been shown to prolong DFS or OS, and current data do not support its use outside clinical trials. The latest United Kingdom Co-ordinating Committee on Cancer Research meta-analysis of ten randomised trials that used adjuvant rIFNalpha has shown that there is a benefit in DFS but not OS. No conclusions can be reached for intermediate-dosage IFNalpha (5 to 10MU) until the mature results of the European Organization for Research and Treatment of Cancer (EORTC) study 18952 are available. In RCC, current evidence does not support the use of adjuvant IFNalpha. In metastatic malignant melanoma and RCC, reported response rates to rIFNalpha are approximately 15%. In a minority of responding patients, however, these responses can be long-standing. In metastatic malignant melanoma, IFNalpha combined with other cytotoxic agents with or without interleukin-2 has achieved high response rates but has not improved survival. In metastatic RCC, intermediate dosages of rIFNalpha should be used and therapy should probably be prolonged (>12 months); response depends on prognostic factors such as good performance status, whereas survival is affected by factors such as low tumour burden. Nephrectomy should therefore be considered in patients with good performance status prior to IFNalpha immunotherapy in advanced RCC, even in patients with metastatic disease. The toxicity of high-dosage IFNalpha and the lack of definite benefit on OS with high- or low-dosage IFNalpha do not support its use outside clinical trials. Data from the ongoing US Intergroup studies, the ongoing EORTC 18991 study (long-term therapy with pegylated IFNalpha) and mature data from EORTC 18952 (intermediate-dosage IFNalpha) will help establish the role of IFNalpha as adjuvant therapy in malignant melanoma.

Prognostic and predictive factors of immunotherapy in metastatic renal cell carcinoma

Metastatic renal cell carcinoma has a poor prognosis. The value of immunotherapy with IFN-alpha and IL-2 both as single agent or as the combination is extensively investigated. The optimal dose and schedule is not known. In various studies response rates vary between 10 and 40%. The duration of response is variable. For a partial response a median duration between 10 and 12 months is given. Complete responses are sometimes long-lasting (a couple of years). The toxicity is drug, dose and schedule dependent. On the basis of a number of prognostic factors, such as performance score, time between the initial diagnosis and the treatment of metastases and the number of metastatic sites, patients can be divided in different prognostic groups. Patients who are classified in the good or intermediate prognostic group may have an improvement of their survival after immunotherapy and therefore they are candidates for immunotherapy.

Synergistic anti-tumor activity of a novel immunomodulator, BCH-1393, in combination with cyclophosphamide

N,N-dimethylaminopurine pentoxycarbonyl D-arginine (BCH-1393) is a novel low molecular weight synthetic immunomodulator that has been shown to significantly stimulate cytotoxic T-lymphocyte responses both in vitro and in vivo (Zacharie B, Gagnon L, Attardo G, Connolly TP, St-Denis Y, Penney CL. Synthesis and activity of 6-substituted purine linker amine immunostimulants. J. Med. Chem. 1997;40:2883-94). Prompted by this evidence, we extended evaluation of BCH-1393 for anticancer activity in syngeneic mouse experimental tumor models. Consistent with previous findings, in vitro assessment of BCH-1393 activity demonstrated a significant increase in the CTL responses in the range of 10(-9)-10(-5) M. Treatment of mice with four consecutive daily intraperitoneal injections at 25 and 50 mg/kg resulted in a significant increase of the relative percentage of blood CD4+, CD8+, NK and monocyte subsets without any evidence of toxicity. In vivo anti-tumor activity of BCH-1393 was evaluated, either alone or in combination with subtherapeutic doses of cyclophosphamide (Cy), against weakly immunogenic mouse breast carcinoma DA-3 and strongly immunogenic colon adenocarcinoma MC38. Daily intraperitoneal injection of BCH-1393 at 50 mg/kg alone was well tolerated but produced a relatively weak anti-tumor effect in both tumor models. However, a significant inhibition of tumor outgrowth and suppression of established tumor growth was observed when BCH-1393 was administered in combination with subtherapeutic doses of Cy. Combination treatment of 50 mg/kg BCH-1393 with 100 mg/kg Cy (given as single intravenous bolus injection) starting 2 days prior to DA-3 tumor cell inoculation prevented tumor outgrowth in 70-80% of treated mice. In the remaining 20-30% of mice that had developed tumors, a nearly complete (90%) tumor growth inhibition was observed at days 22-24 post tumor implant. In the MC38 tumor model, combination treatment of established tumors with BCH-1393 and Cy (CTX) at 50 mg/kg resulted in a significant delay in tumor growth compared to CTX treatment alone. The observed concomitant anti-tumor activity of BCH-1393 with cyclophosphamide warrants further investigation of this immunomodulator as an adjunctive treatment of cancer.

Immunotherapy of malignant melanoma

Immunotherapy and biologic therapy of malignant melanoma are based on a sound scientific rationale and show promising preliminary results. As the nature of immune response to melanoma becomes further characterized, it is likely that more specific immune manipulations may be approached clinically. The fact that complete and partial remissions are induced in some patients with metastatic malignant melanoma by INF-alpha, IL-2, LAK cells, TIL cells, tumor vaccines, and the like clearly indicates a potential role for immunotherapy. As the overall response rates to these maneuvers are only in the range of 20%, more basic research is needed to understand more fully the immune mechanisms of tumor rejection. The combination of chemotherapy with biologic therapy has also provided promising leads. A major area waiting for development is the use of immunotherapy and biologic therapy as adjuvant treatment for the prevention of recurrence after surgical removal of high-risk Stage I/II and Stage III disease. The future of immunotherapy, either specific active immunization with appropriate vaccines or adoptive immunotherapy, must be based on well-defined molecules and antigenic systems, with appropriate enhancement based on the principles of immune reaction. Numerous strategies may be developed to enhance immune response, with resultant activation and proliferation of effector cells, including MHC- and non-MHC-restricted cytotoxic effector cells against tumor cells. The practice and principles of immunotherapy of human melanoma may be applied to other solid tumors that are resistant to chemotherapy and radiation therapy. Further experimentation in immunotherapy trials of melanoma may result in reliable and predictable clinical responses.

Medical treatment of advanced renal cell carcinoma: present options and future directions

The treatment of patients with metastatic renal cell carcinoma (MRCC) continues to be disappointing. A large number of hormones, chemotherapeutic agents and combinations have been tested with poor and non-reproducible results. Among the immunological treatments investigated in MRCC, the best results have been claimed with interferons (IFNs) and interleukin-2 (IL-2) and, although no randomized studies have shown higher activity than cytotoxic drugs, hormones or even no treatment, many oncologists feel it justified to consider these biologic agents the treatment of choice for this disease. Of patients treated with alpha-IFN, 15-20% achieve an objective remission and 3-5% achieve a long-lasting complete response. No substantial increase of the therapeutic activity of alpha-IFN was produced by combination with chemotherapeutic agents and gamma-IFN or tumour necrosis factor. High doses of IL-2 with or without lymphokine-activated killer cells led to successful results in about 20-30% of patients with 5-10% complete responses. More recently, less toxic regimens with lower doses of IL-2 alone or combined with alpha-IFN produce similar response rates. Many studies have clarified the importance of prognostic factors in patient selection for response and survival during treatments with IFNs and IL-2. Good performance status, a long interval from diagnosis to treatment, and only one site of disease seem to be the most important predictors for survival. Both IFNs and IL-2 appear to possess encouraging antitumour activity in patients with favourable prognostic factors, but further studies are needed to identify the treatment of choice, the optimal dose regimen and route of administration in this subgroup of patients. Patients with poor prognosis should be encouraged to enter controlled studies aimed to evaluate investigational drugs and new therapeutic methods.

[Immunotherapy of malignant melanoma. New prospects]

Malignant melanoma is an immunogenic tumor which can induce host humoral and cellular responses, and is a good model for development of anti-cancer immunotherapy. During the last decade systemically-administrated interferon and interleukin-2 have been used. Advances in immunology and molecular biology could allow a more specific and active immunotherapy. Perspectives include chemo-immunotherapy, monoclonal antibodies alone or in combination with cytotoxic agents, adoptive immunotherapy with tumor-infiltrating lymphocytes (TIL), gene therapy designed to increase tumor immunogenicity, and active immunotherapy with vaccines.

Peri-operative modulation of cellular immunity in patients with colorectal cancer

The peri-operative cellular immune response is depressed in patients with gastrointestinal cancer, a factor which may facilitate malignant dissemination. We have investigated the effects of peri-operative rIL-2 and a combination of rIL-2 and interferon-alpha (IFN-alpha) on both peripheral blood lymphocyte function and number in patients undergoing surgical resection for colorectal cancer. Fifty-two patients were randomly allocated to either control, rIL-2 or rIL-2 with IFN-alpha treatment arms. In vitro studies were performed pre-operatively and on post-operative days 1, 4, 7 and 10. Natural killer (NK) and lymphokine-activated killer (LAK) cell function were profoundly depressed in control patients (P < 0.001; P < 0.01), an effect abrogated in both treatment groups; indeed NK function was augmented in the rIL-2 and IFN-alpha group on the first post-operative day in association with an increase in the percentage of cells expressing CD16 and CD56 (P < 0.01). Flow cytometric analysis of lymphocyte subsets in the control group was unremarkable, except for an early post-operative fall in numbers of lymphocytes. Treatment with either rIL-2 or rIL-2 and IFN-alpha produced an initial profound reduction in T lymphocyte numbers, followed by a 'rebound' lymphocytosis of activated CD3+ T cells, as demonstrated by a significant increase in co-expression of CD25, CD38 and CD45RO. No significant differences were observed between either of the treatment groups. Adjuvant immunotherapy affects peri-operative anti-tumour immune responses, and this may influence long term outcome in patients undergoing surgery for gastrointestinal cancer.

Cytokines in tumour therapy

Cytokines are low molecular weight proteins released by cells of the immune system that have therapeutic potential in cancer. They include the interleukins, the interferons, tumour necrosis factor and the colony-stimulating factors. Cytokines are capable of producing significant and sustained responses against a number of tumours. Clinically, the highest response rates to cytokine immunotherapy have been seen in melanoma and renal cell cancer. Current efforts aim to reduce treatment-related toxicity while maintaining the efficacy of cytokines. The therapeutic potential of these agents may be increased with genetic manipulation by introducing genes encoding cytokines into tumour-infiltrating lymphocytes and certain tumour cells. However, immunotherapy remains time consuming and expensive, and further developments are necessary before it can have a definitive role in tumour management.

Treatment of gastrointestinal and renal adenocarcinomas with interferon-alpha

Treatment of adenocarcinomas with interferon-alpha as a single agent has been disappointing. Recent efforts have focused on the combination of interferon with cytotoxic drugs such as 5-fluorouracil. A number of postulated mechanisms can explain synergistic interactions between 5-fluorouracil and interferon-alpha, including interaction with pyrimidine pathways, and alteration of drug metabolism. Previous studies in colorectal cancer, using 5-fluorouracil and interferon-alpha are reviewed, suggesting that the combination is more active than 5-fluorouracil alone. In renal cell carcinoma, the literature is reviewed, suggesting that daily interferon is the most efficacious schedule; preliminary data suggest that addition of 5-fluorouracil to interferon-alpha can double the expected response rate of 16% achieved by interferon-alpha alone.

Rationale for immunotherapy of renal cell carcinoma

Metastasis to distant organs is the principal cause of death from renal cell carcinoma (RCC). No commonly accepted therapy is available for disseminated RCC at present. Immunotherapy is a mode of therapy that either interferes with the immune system or makes use of drugs that have been derived from soluble mediators of the immune system. Several lines of evidence suggest that combinations of genetically engineered cytokines (e.g. interleukin-2 and interferon alpha) may be particularly active in the treatment of advanced RCC. There are two major rationales for considering immunotherapy for RCC: (1) there is currently no other therapy available, and (2) there is hardly any innovative approach besides immunotherapy. Still, immunotherapy is far from being a standard therapy for disseminated RCC.

Clinical evaluation of interferons in malignant melanoma

The evaluation of interferons in the treatment of malignant melanoma has been mainly in the treatment of advanced disease using interferons as the sole agent or in combination with other agents. Studies of the value of interferons as adjuvant therapy in high-risk primary melanoma patients are necessary, but no results have been published to date. Human interferon alpha produces low response rates as a sole agent, but in combination with cimetidine, a 30% response rate has been achieved. Recombinant alpha interferons give responses of 15%-20% in advanced melanomas, and combination with cimetidine does not enhance the response rate. Recombinant alpha interferons have been used in combination with other interferons, cimetidine, monoclonal antibodies, and cytotoxics, with either no or small improvement in response rates. DTIC with recombinant interferon alpha-2a has been shown to produce objective response rates of 26%, with low toxicity and maintenance of quality of life. A randomized trial with DTIC as the sole agent, compared with combination treatment, is being conducted to determine the significance of this finding.