Prime-boost using separate oncolytic viruses in combination with checkpoint blockade improves anti-tumour therapy

The anti-tumour effects associated with oncolytic virus therapy are mediated significantly through immune-mediated mechanisms, which depend both on the type of virus and the route of delivery. Here, we show that intra-tumoral oncolysis by Reovirus induced the priming of a CD8+, Th1-type anti-tumour response. By contrast, systemically delivered Vesicular Stomatitis Virus expressing a cDNA library of melanoma antigens (VSV-ASMEL) promoted a potent anti-tumour CD4+ Th17 response. Therefore, we hypothesised that combining the Reovirus-induced CD8+ T cell response, with the VSV-ASMEL CD4+ Th17 helper response, would produce enhanced anti-tumour activity. Consistent with this, priming with intra-tumoral Reovirus, followed by an intra-venous VSV-ASMEL Th17 boost, significantly improved survival of mice bearing established subcutaneous B16 melanoma tumours. We also show that combination of either therapy alone with anti-PD-1 immune checkpoint blockade augmented both the Th1 response induced by systemically delivered Reovirus in combination with GM-CSF, and also the Th17 response induced by VSV-ASMEL. Significantly, anti-PD-1 also uncovered an anti-tumour Th1 response following VSV-ASMEL treatment that was not seen in the absence of checkpoint blockade. Finally, the combination of all three treatments (priming with systemically delivered Reovirus, followed by double boosting with systemic VSV-ASMEL and anti-PD-1) significantly enhanced survival, with long-term cures, compared to any individual, or double, combination therapies, associated with strong Th1 and Th17 responses to tumour antigens. Our data show that it is possible to generate fully systemic, highly effective anti-tumour immunovirotherapy by combining oncolytic viruses, along with immune checkpoint blockade, to induce complementary mechanisms of anti-tumour immune responses.

Detection of candidate biomarkers of prostate cancer progression in serum: a depletion-free 3D LC/MS quantitative proteomics pilot study

BACKGROUND

Prostate cancer (PCa) is the most common male cancer in the United Kingdom and we aimed to identify clinically relevant biomarkers corresponding to stage progression of the disease.

METHODS

We used enhanced proteomic profiling of PCa progression using iTRAQ 3D LC mass spectrometry on high-quality serum samples to identify biomarkers of PCa.

RESULTS

We identified >1000 proteins. Following specific inclusion/exclusion criteria we targeted seven proteins of which two were validated by ELISA and six potentially interacted forming an 'interactome' with only a single protein linking each marker. This network also includes accepted cancer markers, such as TNF, STAT3, NF-κB and IL6.

CONCLUSIONS

Our linked and interrelated biomarker network highlights the potential utility of six of our seven markers as a panel for diagnosing PCa and, critically, in determining the stage of the disease. Our validation analysis of the MS-identified proteins found that SAA alongside KLK3 may improve categorisation of PCa than by KLK3 alone, and that TSR1, although not significant in this model, might also be a clinically relevant biomarker.

Spontaneous antibodies against Engrailed-2 (EN2) protein in patients with prostate cancer

We reported the expression of the homeodomain-containing transcription factor Engrailed-2 (EN2) in prostate cancer and showed that the presence of EN2 protein in the urine was highly predictive of prostate cancer. This study aimed to determine whether patients with prostate cancer have EN2 autoantibodies, what the prevalence of these antibodies is and whether they are associated with disease stage. The spontaneous immunoglobulin (Ig)G immune response against EN2 and for comparison the tumour antigen New York Esophageal Squamous Cell Carcinoma 1 (NY-ESO-1), were tested by enzyme-linked immunosorbent assay (ELISA) in three different cohorts of prostate cancer patients as well as a group of men genetically predisposed to prostate cancer. Thirty-two of 353 (9·1%) of the SUN cohort representing all stages of prostate cancer demonstrated EN2 IgG responses, 12 of 107 patients (11·2%) in the advanced prostate cancer patients showed responses, while only four of 121 patients (3·3%) with castrate-resistant prostate cancer showed EN2 autoantibodies. No significant responses were found in the predisposed group. Anti-EN2 IgG responses were significantly higher in patients with prostate cancer compared to healthy control males and similarly prevalent to anti-NY-ESO-1 responses. While EN2 autoantibodies are not a useful diagnostic or monitoring tool, EN2 immunogenicity provides the rationale to pursue studies using EN2 as an immunotherapeutic target.

Lymphokine-activated killer and dendritic cell carriage enhances oncolytic reovirus therapy for ovarian cancer by overcoming antibody neutralization in ascites

Reovirus is an oncolytic virus (OV), which acts by both direct tumor cell killing and priming of antitumor immunity. A major obstacle for effective oncolytic virotherapy is effective delivery of OV to tumor cells. Ovarian cancer is often confined to the peritoneal cavity and therefore i.p. delivery of reovirus may provide the ideal locoregional delivery, avoiding systemic dissemination. However, ovarian cancer is associated with an accumulation of ascitic fluid, which may interfere with oncolytic viral therapy. Here, we investigated the effect of ascites on reovirus-induced oncolysis against primary ovarian cancer cells and ovarian cancer cell lines. In the absence of ascites, reovirus was cytotoxic against ovarian cancer cells; however, cytotoxicity was abrogated in the presence of ascitic fluid. Neutralizing antibodies (NAb) were identified as the cause of this inhibition. Loading OV onto cell carriers may facilitate virus delivery in the presence of NAb and immune cells which have their own antitumor effector activity are particularly appealing. Immature dendritic cells (iDC), Lymphokine-activated killer (LAK) cells and LAKDC cocultures were tested as potential carriers for reovirus for tumor cell killing and immune cell priming. Reovirus-loaded LAKDC, and to a lesser degree iDC, were able to: (i) protect from NAb and hand-off reovirus for tumor cell killing; (ii) induce a proinflammatory cytokine milieu (IFNɣ, IL-12, IFNα and TNFα) and (iii) generate an innate and specific antitumor adaptive immune response. Hence, LAKDC pulsed with reovirus represent a novel, clinically practical treatment for ovarian cancer to maximise both direct and innate/adaptive immune-mediated tumor cell killing.

Recent clinical experience with oncolytic viruses

There has been interest in using viruses to treat cancer for over a century. Recent clinical efforts, driven on by significant preclinical advances, have focussed on the safety of using replication-competent viruses. Recently published clinical trials of six oncolytic viruses (adenovirus, reovirus, measles, herpes simplex, Newcastle disease virus and vaccinia) have added to the accumulating data that endorse oncolytic viruses as a safe and well tolerated treatment approach. Conclusive evidence of efficacy remains to be demonstrated, but randomised clinical trials are now underway.

Measles virus causes immunogenic cell death in human melanoma

Oncolytic viruses (OV) are promising treatments for cancer, with several currently undergoing testing in randomised clinical trials. Measles virus (MV) has not yet been tested in models of human melanoma. This study demonstrates the efficacy of MV against human melanoma. It is increasingly recognised that an essential component of therapy with OV is the recruitment of host antitumour immune responses, both innate and adaptive. MV-mediated melanoma cell death is an inflammatory process, causing the release of inflammatory cytokines including type-1 interferons and the potent danger signal HMGB1. Here, using human in vitro models, we demonstrate that MV enhances innate antitumour activity, and that MV-mediated melanoma cell death is capable of stimulating a melanoma-specific adaptive immune response.

Locoregional intravascular viral therapy of cancer: precision guidance for Paris's arrow?

Viral therapy of cancer includes strategies such as viral transduction of tumour cells with 'suicide genes', using viral infection to trigger immune-mediated tumour cell death and using oncolytic viruses for their direct anti-tumour action. However, problems still remain in terms of adequate viral delivery to tumours. A role is also emerging for single-organ isolation and perfusion. Having begun with the advent of isolated limb perfusion for extremity malignancy, experimental systems have been developed for the perfusion of other organs, particularly the liver, kidneys and lungs. These are beginning to be adopted into clinical treatment pathways. The combination of these two modalities is potentially significant. Locoregional perfusion increases the exposure of tumour cells to viral agents. In addition, the avoidance of systemic elimination through the immune and reticulo-endothelial systems should provide a mechanism for increased transduction/infection of target cells. The translation of laboratory research to clinical practice would occur within the context of perfusion programmes, which are already established in the clinic. Many of these programmes include the use of vasoactive cytokines such as tumour necrosis factor-alpha, which may have an effect on viral uptake. Evidence of activation of specific anti-tumour immunological responses by intratumoural and other existing methods of viral administration raises the intriguing possibility of a locoregional therapy, with the ability to affect distant sites of disease. In this review, we examined the state of the literature in this area and summarized current findings before indicating likely areas of continuing interest.

Inhibition of the aquaporin 3 water channel increases the sensitivity of prostate cancer cells to cryotherapy

Aquaporins (AQPs) are intrinsic membrane proteins that facilitate selective water and small solute movement across the plasma membrane. In this study, we investigate the role of inhibiting AQPs in sensitising prostate cancer cells to cryotherapy. PC-3 and DU145 prostate cancer cells were cooled to 0, −5 and −10°C. The expression of AQP3 in response to freezing was determined using real-time quantitative polymerase chain reaction (RT–qPCR) and western blot analysis. Aquaporins were inhibited using mercuric chloride (HgCl₂) and small interfering RNA (siRNA) duplex, and cell survival was assessed using a colorimetric assay. There was a significant increase in AQP3 expression in response to freezing. Cells treated with AQP3 siRNA were more sensitive to cryoinjury compared with control cells (P<0.001). Inhibition of the AQPs by HgCl₂ also increased the sensitivity of both cell lines to cryoinjury and there was a complete loss of cell viability at −10°C (P<0.01). In conclusion, we have shown that AQP3 is involved directly in cryoinjury. Inhibition of AQP3 increases the sensitivity of prostate cancer cells to freezing. This strategy may be exploited in the clinic to improve the efficacy of prostate cryotherapy.

Results of a phase I study to evaluate the feasibility, safety, and biological effects of intravenous administration of wild-type reovirus with docetaxel to patients with advanced malignancies

e13524

Background: Reovirus has minimal pathogenicity in humans but selectively replicates in cells with activated Ras. Wild- type reovirus serotype 3 Dearing strain (Reolysin) has selective antitumor activity in vitro, in murine models, and after systemic delivery in humans in phase 1 trials. Synergistic tumour kill has been observed combining reovirus with taxanes in a range of cancer cell lines and in vivo. Methods: Patients were treated in an open-label, dose-escalating, phase I trial and received 3- weekly 75mg/m2 docetaxel i.v. and reovirus i.v. (day 1–5 of first week inclusive). Reovirus was administered at a starting dose of 3x109 tissue culture infectious dose (TCID50) and then increased to 1 x 1010 and 3 x 1010 TCID50. Primary endpoints were to determine the maximum tolerated dose (MTD), dose limiting toxicity (DLT) and to recommend a dose and schedule for future investigation. Secondary endpoints were to evaluate pharmacokinetics, neutralizing antibody development, cell- mediated immune response and anti-tumour activity. Results: 17 patients were treated (15 males, median age 60 years). No MTD has been reached. DLT's observed were G4 neutropenia (and a recurrent perianal abcess) and G3 rise in AST. Other toxicities observed were fatigue, hypotension and neutropenic sepsis. At present, 5 patients remain on treatment. We have observed 2 partial responses (breast and gastric carcinoma) and 10 patients had stable disease as best response. Conclusions: Reovirus is well tolerated when administered in combination with intravenous docetaxel, with predictable toxicity observed. The recommended dose has been defined at 3x1010 TCID50 and phase II studies are planned. Objective radiological evidence of anticancer activity for this combination has been observed.

[Table: see text]

Reovirus: viral therapy for cancer 'as nature intended'

Oncolytic viruses are tumour selective and able to lyse cancer cells after infection. Reovirus is an example of a wild-type oncolytic virus and is currently being investigated as a potential novel therapy for cancer. This overview gives a brief description of what is known about reovirus biology and summarises the preclinical data related to its oncolytic ability. The completed and ongoing clinical trials involving reovirus, both as a single agent and in combination with chemotherapy and radiotherapy, will be reviewed and their results discussed. Many of these clinical studies are being conducted by centres in the UK.

Phase I trial of intratumoral administration of reovirus type 3 with radiation in patients with advanced malignancies

14009

Background: Reoviruses are RNA viruses that replicate preferentially in cells with aberrant Ras-pathway signaling. Preclinical data have shown that the combination of reovirus (REO) and radiation (RT) significantly increases RT-induced cytotoxicity. Methods: Patients (pts) with measurable disease amenable to treatment with localised short-course palliative RT were enrolled in cohorts of 3. In the first stage, pts received local tumour RT (20 Gy in 5 fractions) in combination with two intratumoural injections of escalating REO doses to a maximum of 1010 TCID50. If no dose-limiting toxicity (DLT), pts received local tumour RT (36 Gy in 12 fractions) in combination with two, four or six doses of REO at TCID50. Endpoints were safety, viral replication, immunogenicity and antitumoral activity. Results: Eighteen pts have been treated to date with a variety of solid tumours.Two pts, one at the 1 x 109 dose and one at 1 x 1010 refused to receive the second REO injection due to grade 2 flu-like symptoms. Other toxicities have been mild (grade 1–2) and have included fever, sweating, skin erythema. There has been no evidence of exacerbation of the acute RT reaction. Reverse transcription polymerase chain reaction (RT-PCR) studies of blood, urine, stool and sputum on day 8 post-REO administration were negative for viral shedding for all treated pts. The induction of neutralising anti-REO antibodies was attenuated compared with previous experience in pts receiving intravenous infusions. Three pts (oesophageal ,skin squamous and colorectal carcinoma) had significant partial responses. In addition, the pt. with metastatic oesophageal cancer had a volume reduction of 15% in non-irradiated mediastinal disease for more than 6 months. Intratumoral viral replication by electron microscopy and immunohistochemistry of pre- and post-treatment tumour biopsies was performed. Conclusions: The combination of intratumoral REO and radiation is well tolerated. Promising indicators of synergistic effect are observed. Recruitment is ongoing at the last cohort of the trial.

No significant financial relationships to disclose.

Final results of a phase I study of wild-type oncolytic reovirus administered intravenously to patients with advanced cancer

3572

Background: Reovirus has minimal pathogenicity in humans but selectively replicates in cells with activated Ras, which inactivates the anti-viral effects of double stranded RNA-activated protein kinase. Wild-type reovirus serotype 3 Dearing has selective antitumor activity in pre-clinical models. Methods: Wild-type reovirus serotype 3 Dearing was administered as a 1-hr IV infusion every 4 weeks, initially for 1 day, then for 3 and then 5 days every 4 weeks. The starting dose was 1 x 10^8 tissue culture infectious dose (TCID50), increasing in successive cohorts until the observation of grade 2 toxicity. Endpoints were safety, detection of viral replication, viral shedding, immune response and antitumor activity. Results: A total of 33 patients (25 males, median age 61; ECOG performance status 0/1/2 = 15/17/1) were treated. 8 cohorts were treated at dose levels of 1x10^8 TCID50 for 1 day, 1x10^8 for 3 days, and 1x10^8, 3x10^8, 1x10^9, 3x10^9, 1x10^10 and 3x10^10 for 5 days. Maximum tolerated dose (MTD) was not reached and toxicities were mild (grade 1 or 2), including chills, fever, headache, rhinorrhea, fatigue and myelosuppression. Reverse transcription polymerase chain reaction (RT-PCR) studies of blood, urine, stool and sputum post reovirus administration and every week thereafter were negative for viral shedding for all treated patients. Anti-reovirus antibodies were present at baseline in most patients, and titres increased after cycle 1 by between 1- and 4-log. Intratumoral reovirus replication was detected by electron microscopy in tumor biopsies. PSA decreased by 50% in a patient with metastatic prostate cancer treated at 3x10^9 TCID50, with evidence of tumor necrosis on CT scanning. 2 patients with metastatic colorectal cancer treated at 3x10^8 and 3x10^9 TCID50 had CEA reductions of 60% and 27%, and received 6 and 3 cycles respectively. 1 patient with metastatic bladder cancer treated at 1x10^9 TCID50 had a minor response and received 4 cycles. Conclusions: Wild-type reovirus serotype 3 Dearing is well tolerated, with minimal toxicity, and MTD has not been reached. Despite a vigorous host response to virus, tumor necrosis associated with intratumoral viral replication was observed. Clinical indications of anticancer activity were seen and phase II studies are planned.

[Table: see text]

Low Dose Metronomic Oral Cyclophosphamide for Hormone Resistant Prostate Cancer: A Phase II Study

PURPOSE

Cyclophosphamide is a bifunctional alkylating agent long associated with immune activation. Continuous, uninterrupted, low (so-called metronomic) doses of cyclophosphamide can lead to enhanced immunity against a variety of antigens possibly by targeting regulatory T cells and/or tumor angiogenesis. In this study we tested the observations from animal models and evaluated the safety and efficacy of continuous low dose oral cyclophosphamide in patients with hormone resistant prostate cancer.

MATERIALS AND METHODS

A total of 80 patients were recruited during a 2-year period and 58 received at least 2 cycles (8 weeks) of 50 mg/m(2) oral cyclophosphamide to be included in the safety and intent to treat analysis.

RESULTS

Metronomic cyclophosphamide was safe and well tolerated, and although lymphopenia (up to grade 3) was observed in a third of all patients, there were no clinical complications. The response rate was 34.5% inclusive of objective and prostate specific antigen (absolute reduction and reduction in prostate specific antigen velocity). The median duration of response was 7.5 months (range 3 to 18).

CONCLUSIONS

Oral cyclophosphamide can be used on a metronomic basis safely in men with hormone resistant prostate cancer. The efficacy, low toxicity, low cost and ease of administration of cyclophosphamide justifies further studies in prostate cancer in combination with other agents.

Loss of expression of antigen-presenting molecules in human pancreatic cancer and pancreatic cancer cell lines

Tumours evade immune recognition and destruction through loss or down-regulation of expression of antigen processing and antigen-presenting molecules such as the human leucocyte antigen (HLA class I) and transporter for antigen presentation (TAP). This study examined the expression of HLA class I, class II and TAP in human pancreatic carcinoma tissue and 19 immortalized pancreatic cancer lines using a panel of antibodies directed against allele-specific as well as monomorphic determinants of these molecules. In tissue samples, reduction or loss of HLA class I and TAP was observed in 76% of cases, loss or down-regulation of TAP expression in 53%. In pancreatic cell lines down-regulation or loss of class I and TAP expression was also observed frequently. However, reductions in class I and TAP expression were reversible upon exposure to interferon-gamma in vitro, suggesting a regulatory rather than structural defect in these genes. De novo class II expression was observed in 26% of tumours and 42% of cell lines and may reflect the differentiation status of the cells. The high rate of class I and TAP loss has implications for immunotherapy strategies for pancreatic cancer, as such changes could facilitate a selective growth advantage for malignant cells. However, the reinduction of expression of these molecules with cytokines such as interferon-gamma may ultimately allow their cytotoxic T cell-mediated destruction.

Persistently high levels of immunosuppressive cytokines in patients after radical prostatectomy

A significant proportion of men undergoing 'curative' radical prostatectomy (RP) for organ-confined prostate cancer relapse within 5 years. A number of adverse risk factors have been identified, but to date no adjuvant treatment as improved the outlook for these men. We proposed that these patients, despite small tumour burdens, may be immunosuppressed from their cancer, which may be amenable to immune modulation. We investigated their immune profile using sensitive functional cytokine assays, both pre- and post-surgery. In comparison with controls, RP patients expressed higher levels of both T helper type 1 (Th1) (interleukin (IL)-2 and tumour necrosis factor-alpha) and Th2 cytokines (IL-4, -5 and -10) with little change after removal of tumour. Further analysis based on known poor-prognostic factors indicated a trend to expression of higher levels of Th2 cytokines IL-4 and IL-5 in worse prognosis patients rather than the mixed Th1/2 found across the whole cohort. Persistently high levels of both Th1 and Th2 cytokines were detected in RP compared to control patients, despite the removal of relatively small tumour burdens. Cytokine expression studies may be useful as surrogate marker of potential disease progression, and could be used to identify patients who may benefit from immune modulation post-surgery.

A phase I study of reolysin given intravenously to patients with advanced malignancies

3064

Background: Reovirus is a double-stranded RNA virus with minimal pathogenicity in humans that selectively replicates in cells with activated Ras. Activated Ras inhibits the anti-viral effects of double stranded RNA-activated protein kinase (PKR). Reovirus serotype 3 Dearing has selective antitumor activity, in vitro and in tumour xenograft models. Methods: Reolysin was administered as a 1-hr IV infusion every 4-weeks initially for one day; then 3 days then 5-days every 4 weeks. The starting dose was 1×108 tissue culture infectious dose (TCID50) increasing in successive cohorts until observation of drug-related toxicity ≥ grade 2. Endpoints were safety, viral replication, viral shedding, evaluation of immune response and antitumor activity. Results: 24 patients (pts) (median age 60; ECOG 1, 16 males) have been entered into the first 7 cohorts at the following dose levels: 1×108 for 1-day, 1×108 for 3-days and 1×108, 3×108, 1×109, 3×109 and 1×1010 TCID50 for 5-days. A maximum tolerated dose (MTD) has not been reached and no dose-limiting toxicities have been observed. Toxicities have been mild (grade 1 or 2) and have included chills, fever, headache, runny nose, fatigue and myelosuppression. Reverse transcription polymerase chain reaction (RT-PCR) studies of blood, urine, stool and sputum post reovirus administration were negative for viral shedding for all treated pts. All but one pt had neutralising anti-reovirus antibodies detectable pre-treatment. Titres increased after 1-week of treatment and remained high during subsequent courses of treatment. Two pts with metastatic colorectal cancer treated at 3×108 and 3×109 TCID50 had CEA tumour marker reduction by 60% and 27% receiving 6 and 3 courses of treatment respectively. One pt with metastatic pancreatic cancer received 4 courses of treatment with stable disease. One pt with metastatic prostate cancer had a 50% decrease in PSA after treatment at 3×109 TCID50, with evidence of tumor necrosis on CT scanning. Intratumoral reovirus replication has been detected by electron microscopy in tumur biopsies. Conclusions: Reolysin is well tolerated with minimal toxicity. No viral shedding has been detected. Virus-induced tumor necrosis associated with intratumor viral replication after systemic delivery has been observed.

[Table: see text]

Phase II study of oral capecitabine in patients with hormone-refractory prostate cancer

BACKGROUND

Currently available treatment for hormone refractory prostate cancer is limited in efficacy and associated with significant toxicity. This phase II study was performed to assess the efficacy of the oral fluoropyrimidine capecitabine in advanced prostate cancer.

PATIENTS AND METHODS

Patients who had a rising prostate-specific antigen (PSA) despite androgen withdrawal, but who remained free from cancer-related symptoms. In total, 14 patients received oral capecitabine 1250 mg/m2 twice daily for two weeks of a three-week cycle. Tumour response was assessed using serum PSA measurement at 3-weekly intervals and, where present, imaging of soft tissue metastases.

RESULTS

One of 14 patients experienced a partial response as assessed by both PSA and imaging of liver metastases. In seven other patients (50%), treatment decreased the rate of PSA rise. The duration of PSA stabilisation was generally short, but in 5/14 patients (36%) was sustained beyond 18 weeks, and in one patient to 24 weeks. Toxicity was significant but manageable, the most common adverse events being nausea, mucositis and hand-foot syndrome, each occurring in 50% of patients. Other common side effects were diarrhoea and lymphopenia. All toxicities were grade 1 or 2, except for grade 3 hand-foot syndrome occurring in one patient, and no dose reduction was required because of toxicity.

CONCLUSION

Capecitabine has limited activity as a single agent in prostate cancer, but appears to modulate tumour biology. Considering the added convenience of oral administration, these results support further evaluation of combinations containing capecitabine in hormone-refractory prostate cancer.

Immunosuppressive effects of radiation on human dendritic cells: reduced IL-12 production on activation and impairment of naive T-cell priming

Dendritic cells (DC) are professional antigen-presenting cells (APC) of the immune system, uniquely able to prime naive T-cell responses. They are the focus of a range of novel strategies for the immunotherapy of cancer, a proportion of which include treating DC with ionising radiation to high dose. The effects of radiation on DC have not, however, been fully characterised. We therefore cultured human myeloid DC from CD14+ precursors, and studied the effects of ionising radiation on their phenotype and function. Dendritic cells were remarkably resistant against radiation-induced apoptosis, showed limited changes in surface phenotype, and mostly maintained their endocytic, phagocytic and migratory capacity. However, irradiated DC were less effective in a mixed lymphocyte reaction, and on maturation produced significantly less IL-12 than unirradiated controls, while IL-10 secretion was maintained. Furthermore, peptide-pulsed irradiated mature DC were less effective at naive T-cell priming, stimulating fewer effector cells with lower cytotoxicity against antigen-specific targets. Hence irradiation of DC in vitro, and potentially in vivo, has a significant impact on their function, and may shift the balance between T-cell activation and tolerization in DC-mediated immune responses.

The common heat shock protein receptor CD91 is up-regulated on monocytes of advanced melanoma slow progressors

Despite advances in our understanding of tumour immunology there is no therapy of proven survival benefit for advanced melanoma. Nevertheless, disease progression is slow in a small proportion of patients with metastatic melanoma, suggesting a contribution to outcome from host factors. Recent data have indicated the importance of the heat shock protein receptor CD91 in immune responses to, and progression of, infectious disease. Here we investigate the relationship between CD91 expression and outcome in malignancy. Rare melanoma patients were recruited with advanced disease that was progressing unusually slowly. CD91 expression on their monocytes was compared with control patients with more typical rapidly advancing metastatic disease. Th1 and Th2 cytokines, as well as innate and adaptive immune subsets, were also measured in the two groups. A significant increase in median CD91 expression levels was observed in slow progressors (P = 0.006). There were no differences in other immune subset markers or inflammatory cytokines. The ability of CD91 to internalize and cross-present tumour antigens through the major histocompatibility complex class I pathway may maintain CD8-positive cytotoxic T cell responses and contribute to slow progression of advanced melanoma.

Phase I study to determine the safety, tolerability and immunostimulatory activity of thalidomide analogue CC-5013 in patients with metastatic malignant melanoma and other advanced cancers

We assessed the safety, tolerability and efficacy of the immunomodulatory drug, CC-5013 (REVIMID™), in the treatment of patients with metastatic malignant melanoma and other advanced cancers. A total of 20 heavily pretreated patients received a dose-escalating regimen of oral CC-5013. Maximal tolerated dose, toxicity and clinical responses were evaluated and analysis of peripheral T-cell surface markers and serum for cytokines and proangiogenic factors were performed. CC-5013 was well tolerated. In all, 87% of adverse effects were classified as grade 1 or grade 2 according to Common Toxicity Criteria and there were no serious adverse events attributable to CC-5013 treatment. Six patients failed to complete the study, three because of disease progression, two withdrew consent and one was entered inappropriately and withdrawn from the study. The remaining 14 patients completed treatment without dose reduction, with one patient achieving partial remission. Evidence of T-cell activation was indicated by significantly increased serum levels of sIL-2 receptor, granulocyte–macrophage colony-stimulating factor, interleukin-12 (IL-12), tumour necrosis factor-α and IL-8 in nine patients from whom serum was available. However, levels of proangiogenic factors vascular endothelial growth factor and basic foetal growth factor were not consistently affected. This study demonstrates the safety, tolerability and suggests the clinical activity of CC-5013 in the treatment of refractory malignant melanoma. Furthermore, this is the first report demonstrating T-cell stimulatory activity of this class of compound in patients with advanced cancer.

Advances in prostate cancer immunotherapy

Metastatic prostate cancer remains incurable. Harnessing the body's own immune system to control or eradicate tumours has long been an attractive concept. Only recently has the field of tumour immunology provided the basic science behind the mechanisms of tumour genesis, molecular basis of the recognition of tumour associated antigens and the interactions of the antigen-presenting cells with effector cells. This research has been translated into numerous clinical immunotherapy strategies, which have reached the oncology clinic and which should provide options for our patients.

The role of autologous transplantation in patients with multiple myeloma aged 65 years and over

Autologous stem cell transplantation after high-dose melphalan for the treatment with multiple myeloma has resulted in prolonged progression-free survival and overall survival in patients under 65 years. We have examined the role of autologous transplantation in 17 patients with multiple myeloma over 65 years at our centre using a matched pair analysis with younger patients. The median age of this cohort of patients over 65 years was 67 years (65-74) and their outcome and transplant-related morbidity was compared with 17 younger pair mates with a median age of 55 years (31-64). Sixteen patients received high-dose melphalan, and one received busulphan with autologous stem cell rescue. The high-dose therapy was well tolerated in both elderly patients and the matched pairs, with comparable time to recover neutrophils and platelets. Treatment-related mortality also did not differ significantly in both the groups. Median overall survival of the elderly patients was 3.59 years similar to 3.01 years of the pair mates (P = 0.92). Autologous stem cell transplantation after high-dose melphalan conditioning was equally well tolerated in groups of patients above and below 65 years. There was no difference in relapse rate, OS and myelotoxicity in both the groups. These findings suggest that advanced age should not be an exclusion criterion from autologous transplant programmes. Bone Marrow Transplantation (2000) 25, 533-539.

Can immunotherapy by gene transfer tip the balance against colorectal cancer?

Gene therapy, in particular the transfer of genes encoding immunostimulatory molecules (cytokines and costimulatory molecules) as well as selectively cytotoxic enzymes and DNA vaccination, has the potential of enhancing cell mediated immune responses against tumours including those of colorectal origin. Genes can be transferred using viral vectors either to cultured tumour cells in vitro that can be returned to the patient as a "cancer vaccine", or directly to tumour cells in vivo. Vaccination with DNA constructs expressing specific tumour antigens characteristic of colorectal neoplasia can trigger immune recognition and destruction of tumour cells. The aim is to tip the balance from protumour to antitumour mechanisms by generating a local immune response and systemic antitumour immune memory to destroy metastases. Studies in murine models, combined with human studies, show that such approaches could become an adjunct to current treatments for human colorectal cancer in the near future.

E-cadherin expression in bladder cancer using formalin-fixed, paraffin-embedded tissues: correlation with histopathological grade, tumour stage and survival

To determine the potential prognostic value of epithelial cadherin (E-cadherin), a Ca(2+)-dependent cell-cell adhesion molecule, we have analysed its immunoreactivity and cellular localisation in 67 transitional cell carcinomas (TCC) using an avidin-biotin immunoperoxidase technique on formalin-fixed, paraffin-embedded tissues. These results were correlated with histopathological grade, tumour stage, presence of metastases and survival. In addition, 10 cystitis and 11 normal bladder biopsies were evaluated as controls. E-cadherin was expressed in a normal membranous pattern in all normal and 7 of 10 cystitis biopsies. Loss of normal surface E-cadherin expression was found in 3 of 15 superficial tumours and in 48 of 52 invasive cancers. Abnormal immunoreactivity was strictly related to tumour differentiation and stage. Fifteen of 20 well-differentiated (grade I) tumours showed preserved membranous E-cadherin immunoreactivity, while 46 of 47 moderate and poorly differentiated tumours (grades II and III) demonstrated abnormal staining patterns. Loss of membranous E-cadherin immunoreactivity was also associated with advanced tumour stage. There was a significantly higher 5-year survival rate for patients with preserved membranous staining compared with patients with abnormal staining.