High-dose interleukin2 - a 10-year single-site experience in the treatment of metastatic renal cell carcinoma: careful selection of patients gives an excellent outcome

Background

VEGF-targeted therapy has become the mainstay of treatment for majority of mRCC patients. For most patients, benefit is short-lived and therefore treatment remains palliative in intent. HD IL2 is an effective immunotherapy treatment capable of durable remission in some patients but its unselected use has been difficult due to its modest response rate and considerable adverse effects. Using set pathology criteria as a selection tool in clinical practice, we have been able to show improved outcomes in our previous report. Here, we present an updated and extended report of this treatment and seek to explore any pathological, clinical and treatment variables likely to predict better outcomes.

Methods

This is an extension of a previously reported clinical audit, which includes mRCC cases treated with HD IL2 between 2003 and 2013. Since 2006, tumour specimens of potential candidates were routinely reviewed prospectively and stratified into Favourable or Other categories based on constitution of histological growth pattern, namely alveolar or solid versus papillary and/or sarcomatoid architecture; clear cell versus granular cell cytoplasmic morphology. HD IL2 was preferentially offered to patients with Favourable pathology. Outcome evaluation includes response rates, survival, and treatment tolerance. Multivariate analysis was performed to explore potential prognostic and predictive factors.

Results

Among prospectively selected patients with Favourable pathology (n = 106), overall response rate was 48.1 % (51/106) with CR rate of 21.6 % (23/106). Median OS was 58.1 months. Factors associated with significantly better response and/or survival includes favourable pathology pattern, higher cycle 1 tolerance and lower number of metastatic organ sites (<3). CAIX (Carbonic anhydrase 9) has prognostic value but is not predictive of response. Toxicities were those expected of IL2 but were manageable on general medical wards, with no treatment-related death. Importantly most complete responses were durable with 76 % (23/30) cases remained relapse-free (median 39 months follow up) and 2 of the seven who relapsed had had long-term disease free survival after resection of oligometastatic relapse.

Conclusions

Our experience shows that HD IL2 remains an effective and safe treatment in well-selected cases of mRCC. The result in this single-institution patient series confirms similar outcomes to our previously reported retrospective series. Given the prospect of long-term remission, fit patients with Favourable histology and low disease burden should be considered for HD IL2 in an experienced centre. Better understanding has been gained from this in-depth analysis especially the examination of possible response predictors and strategies that can improve treatment outcome.

Electronic supplementary material

The online version of this article (doi:10.1186/s40425-016-0174-5) contains supplementary material, which is available to authorized users.

Final results from the large sunitinib global expanded-access trial in metastatic renal cell carcinoma

BACKGROUND

We report final results with extended follow-up from a global, expanded-access trial that pre-regulatory approval provided sunitinib to metastatic renal cell carcinoma (mRCC) patients, ineligible for registration-directed trials.

METHODS

Patients ⩾18 years received oral sunitinib 50 mg per day on a 4-weeks-on-2-weeks-off schedule. Safety was assessed regularly. Tumour measurements were scheduled per local practice.

RESULTS

A total of 4543 patients received sunitinib. Median treatment duration and follow-up were 7.5 and 13.6 months. Objective response rate was 16% (95% confidence interval (CI): 15-17). Median progression-free survival (PFS) and overall survival (OS) were 9.4 months (95% CI: 8.8-10.0) and 18.7 months (95% CI: 17.5-19.5). Median PFS in subgroups of interest: aged ⩾65 years (33%), 10.1 months; Eastern Cooperative Oncology Group performance status ⩾2 (14%), 3.5 months; non-clear cell histology (12%), 6.0 months; and brain metastases (7%), 5.3 months. OS was strongly associated with the International Metastatic Renal-Cell Carcinoma Database Consortium prognostic model (n=4065). The most common grade 3/4 treatment-related adverse events were thrombocytopenia (10%), fatigue (9%), and asthenia, neutropenia, and hand-foot syndrome (each 7%).

CONCLUSION

Final analysis of the sunitinib expanded-access trial provided a good opportunity to evaluate the long-term side effects of a tyrosine kinase inhibitor used worldwide in mRCC. Efficacy and safety findings were consistent with previous results.

CD3ζ-based chimeric antigen receptors mediate T cell activation via cis- and trans-signalling mechanisms: implications for optimization of receptor structure for adoptive cell therapy

Chimeric antigen receptors (CARs) can mediate redirected lysis of tumour cells in a major histocompatibility complex (MHC)-independent manner, thereby enabling autologous adoptive T cell therapy for a variety of malignant neoplasms. Currently, most CARs incorporate the T cell receptor (TCR) CD3ζ signalling chain; however, the precise mechanisms responsible for CAR-mediated T cell activation are unclear. In this study, we used a series of immunoreceptor tyrosine-based activation motif (ITAM)-mutant and transmembrane-modified receptors to demonstrate that CARs activate T cells both directly via the antigen-ligated signalling chain and indirectly via associated chains within the TCR complex. These observations allowed us to generate new receptors capable of eliciting polyfunctional responses in primary human T cells. This work increases our understanding of CAR function and identifies new avenues for the optimization of CAR-based therapeutic interventions.

A randomized, double-blind phase III study (VEG105192) of pazopanib (paz) versus placebo (pbo) in patients with advanced/metastatic renal cell carcinoma (mRCC): Updated safety results

313

Background: This study evaluated the efficacy and safety of paz in 435 pts with mRCC. The primary endpoint of PFS with paz vs pbo was met with a median PFS of 9.2 vs. 4.2 mo (HR 0.46; p<0.0001) respectively. Final OS was 22.9 mos in paz arm vs. 20.5 mos in pbo (HR 0.91; p=0.224); however, OS was confounded by extensive crossover of pbo pts to paz and other therapies. Two independent analyses to adjust for crossover, IPCW (Inverse Probability of Censoring Weighted) and RPSFT (Rank Preserving Structural Failure Time) suggest an OS benefit with paz;HR 0.504; p=0.002 by IPCW and HR 0.43; p=0.172 by RPFST. At the final OS analysis, pts on the paz arm had a 30% increase or in absolute terms 70 yrs (303.7 yrs from 233.5 yrs) in cumulative exposure since analysis 2 yrs ago (Sternberg; JCO 2010). Updated safety data is reported.

Methods: Pts with clear cell mRCC and measurable disease with no prior treatment or 1 prior cytokine-based trt were randomized (2:1) to paz 800 mg QD or pbo and treated until progression (PD), death, or unacceptable toxicity. Upon PD, pts on the pbo arm could receive paz through a parallel open-label study.

Results: Median exposure duration was nearly doubled in the paz arm vs. pbo (7.4 mo vs. 3.8 mo). In the paz arm, 32% of subjects remained on treatment > than 12 mos, 15% for > 24 mos and 8% for > 36 mos. The mean daily dose of paz was 679 mg. ALT elevations >3xULN occurred in 54 pts; upon interruption of paz, or with continuation (adaptation), 85% of pts had documented recovery, 9% no recovery data and 6% not recovered. Further details regarding these and less frequent class effect AEs such as hand-foot syndrome (6%), myocardial dysfunction (<1%) will be reported.

Conclusions: This safety update reflects a 30% increase in the cumulative exposure to paz since the previous clinical cutoff. There are no significant changes to the type, frequency or severity of AEs and no differences in grade 3, 4, or 5 AEs. No new safety signals have been detected.

[Table: see text]

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An open-label extension study to evaluate safety and efficacy of pazopanib in patients with advanced renal cell carcinoma (RCC)

5110

Background: The efficacy and safety of pazopanib (paz), a multikinase angiogenesis inhibitor, was evaluated in a randomized, double-blind placebo-controlled phase III study (VEG105192), in treatment-naïve and cytokine-pretreated patients (pts) with advanced RCC. Pts with progressive disease (PD) on placebo had the option to receive paz 800 mg QD via an extension study (VEG107769). Methods: Pts with ECOG PS ≤ 2, adequate organ function and no other systemic anticancer treatment since PD on VEG105192 were eligible. The primary endpoint was safety. Secondary endpoints included response rate (RR) per RECIST and progression-free survival (PFS). RR was described along with 95% confidence intervals (CIs). PFS was summarized descriptively using Kaplan-Meier estimates for the median, quartiles and PFS rates at 6, 12, and 18 mo along with approximate 95% CIs. Results: 70 placebo pts were enrolled (+ 1 paz pt as an exemption due to symptom improvement). 34 pts (48%) were treatment-naïve and 37 (52%) were cytokine pretreated (at baseline in VEG105192). Median age was 59 y (25–80); baseline ECOG PS 0 (32%), 1 (52%), and 2 (14%). Median time from randomization to placebo in VEG105192 to start of paz treatment on VEG107769 was 6.4 mo (1–18 mo). At VEG107769 clinical cut-off (May 08), 21 (30%) pts had died, 40 (56%) pts had discontinued paz, and 31 (44%) pts were still on paz. Median exposure to paz was 5.7 mo. Most pts died or discontinued paz due to PD. The majority of adverse events (AEs) were Gr 1/2. Gr 3/4 AEs were experienced by 21%/7% of pts. The most common AEs were hypertension (46%; 4% Gr 3/4), hair color changes (39%; 0% Gr 3/4), diarrhea (38%; 1% Gr 3/4), anorexia (24%; 1% Gr 3/4), and nausea (24%; 0% Gr 3/4). Two pts had fatal AEs: sudden death and gastrointestinal hemorrhage. The most common Gr 3 chemistry laboratory abnormalities were hyponatremia (7%) and elevated ALT (7%) and AST (6%); no Gr 4. RR was 32.4% (95% CI: 21.5, 43.3); median PFS was 8.3 mo (95% CI: 6.1, 11.4 mo). Conclusions: Patients with advanced RCC who developed PD on placebo in a phase III study subsequently achieved clinical benefit from paz treatment in this extension study. These findings support the continued evaluation of paz in advanced RCC.

[Table: see text]

A phase II study of a 5T4 oncofoetal antigen tumour-targeted superantigen (ABR-214936) therapy in patients with advanced renal cell carcinoma

In a phase II study, 43 renal cell carcinoma patients were treated with individualised doses of ABR-214936; a fusion of a Fab recognising the antigen 5T4, and Staphylococcal enterotoxin A. Drug was given intravenously on 4 consecutive days, treatment was repeated 1 month later. Treatment was associated with moderate fever and nausea, but well tolerated. Of 40 evaluable patients, 28 had disease control at 2 months, and at 4 months, one patient showed partial response (PR) and 16 patients stable disease. Median survival, with minimum follow-up of 26 months was 19.7 months with 13 patients alive to date. Stratification by the Motzer's prognostic criteria highlights prolonged survival compared to published expectation. Patients receiving higher drug exposure had greater disease control and lived almost twice as long as expected, whereas the low-exposure patients survived as expected. Sustained interleukin-2 (IL-2) production after a repeated injection appears to be a biomarker for clinical effect, as the induced-IL-2 level on the day 2 of treatment correlated with survival. The high degree of disease control and the prolonged survival suggest that this treatment can be effective. These findings will be used in the trial design for the next generation of drug, with reduced antigenicity and toxicity.

An open label phase I study of ABR-217620, a fusion protein of the 5T4 antibody moiety and an engineered superantigen, in patients with non-small cell lung, renal cell or pancreatic cancer

3083

Background: ABR-217620 (naptumomab estafenatox) is a recombinant fusion protein that consists of the 5T4Fab moiety genetically fused to the engineered superantigen variant SEA/E-120. This fusion protein is a new generation tumor-targeted superantigen based on the previously described ABR-214936 (anatumomab mafenatox). ABR-217620 was designed to reduce antigenicity and toxicity. The 5T4 antigen is expressed on more than 95 % of tumors from patients with non-small cell lung (NSCLC), renal cell (RCC) and pancreatic cancer (PC). In clinical PET studies 124I-labeled ABR-217620 has been shown to localize to 5T4 positive tumors. Methods: The compound was administered as a 5 min bolus infusion for 5 consecutive days. Patients with disease control at day 28 were offered a second cycle of therapy. Dose escalation has been performed using a Bayesian model starting at 0.5 μg/kg/day. The primary endpoint is determination of MTD. Secondary endpoints include characterization of side effects, immunological response, efficacy and pharmacokinetics. Results: 31 patients to date have been treated (19 NSCLC, 8 RCC, 4 PC). 3 patients have had dose limiting toxicities (fever, hypotension and nausea, grade 3) at doses between 23 and 28 μg/kg/day. The side effects were resolved quickly. Based on the experience from ABR-214936, these side effects were expected, but the MTD is ∼ 200 times higher. ABR-217620 leads to a dose dependent systemic increase of cytokines including IL-2 and IFN-γ after infusion. It also leads to an expansion of the superantigen reactive T cell population. 16/29 evaluable patients investigated had SD while 13 patients had PD. In contrast to ABR-214936, the first cycle of ABR-217620 treatment can be given without factoring in the titer of preformed anti-superantigen antibodies. Conclusions: ABR-217620 treatment had predicted and manageable side effects with fever, hypotension and nausea being dose limiting toxicities. Treatment with ABR-217620 resulted in a restricted systemic activation of the immune system. A large fraction of the patients have had stable disease.

[Table: see text]

Phase I/II trial of a PrimeBoost therapeutic vaccine in stage III/IV metastatic melanoma

8030

Background: This trialevaluated the safety, immunogenicity and tumour response of increasing doses of DNA plasmid (DNA.Mel3) and MVA viral vector (MVA.Mel3), containing 7 melanoma epitopes. Methods: 41 HLA-A2 positive stage III/IV melanoma patients with unresectable measurable disease were enrolled. Immunisations were administered three weeks apart with continued MVA.Mel3 boosting in patients with tumour control. Epitope-specific CD8+ T cell responses were evaluated using ex vivo tetramer staining and interferon gamma (IFN-γ) ELISPOT assay. Results: DNA.Mel3 was well tolerated at all doses. Dose-related grade 3 local skin reactions and systemic immune-associated reactions were observed following MVA.Mel3, no reactions led to early study discontinuation. Melan-A tetramer responses were observed in 23/36 (64%) evaluable patients, of which 9/36 showed an IFNγ response to at least one epitope in ELISPOT assay. Seven patients (17%) showed tumour control (PR, MR, or SD >6 months), of which 3/7 patients had associated immune responses, including one with PR > 21 months who underwent extended MVA.Mel3 boosting. Overall median progression free survival was 9 weeks (16 weeks for immune responders). Median overall survival for the intention-to-treat population is 11.7 months with follow up of 16 patients continuing. Conclusions: High dose heterologous PrimeBoost immunisation was safe and stimulated immune responses in >50% of late stage metastatic melanoma patients treated. Tumour control was observed with some evidence of association with immune response.

[Table: see text]

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Engineering T cells for cancer therapy

It is generally accepted that the immune system plays an important role in controlling tumour development. However, the interplay between tumour and immune system is complex, as demonstrated by the fact that tumours can successfully establish and develop despite the presence of T cells in tumour. An improved understanding of how tumours evade T-cell surveillance, coupled with technical developments allowing the culture and manipulation of T cells, has driven the exploration of therapeutic strategies based on the adoptive transfer of tumour-specific T cells. The isolation, expansion and re-infusion of large numbers of tumour-specific T cells generated from tumour biopsies has been shown to be feasible. Indeed, impressive clinical responses have been documented in melanoma patients treated with these T cells. These studies and others demonstrate the potential of T cells for the adoptive therapy of cancer. However, the significant technical issues relating to the production of natural tumour-specific T cells suggest that the application of this approach is likely to be limited at the moment. With the advent of retroviral gene transfer technology, it has become possible to efficiently endow T cells with antigen-specific receptors. Using this strategy, it is potentially possible to generate large numbers of tumour reactive T cells rapidly. This review summarises the current gene therapy approaches in relation to the development of adoptive T-cell-based cancer treatments, as these methods now head towards testing in the clinical trial setting.

Expression of the 5T4 oncofoetal antigen in renal cell carcinoma: a potential target for T-cell-based immunotherapy

The 5T4 oncofoetal antigen is a heavily glycosylated cell surface protein found on human placental trophoblast and on diverse types of human cancer but is not expressed at significant levels on adult human tissues in health. It therefore satisfies the criteria for a tumour-associated antigen and is an ideal target for the immunotherapy of cancer. We report here that 5T4 is strongly expressed on the majority of renal cell carcinomas and therefore this population of patients is suitable for trials of 5T4-targeted therapies. In particular, we have shown that T cells from renal cell carcinoma patients can be genetically modified to kill 5T4 expressing renal cancer cell lines by introduction of a chimeric-signalling protein. This protein consists of a single chain antibody fragment capable of binding antigen directly at the cell surface and then activating the T cell by virtue of a CD3zeta-signalling domain. This is a powerful tool that bypasses a number of mechanisms that allow tumours to escape T-cell killing and can be readily scaled up for clinical use.

Impact of laparotomy and liver resection on the peritoneal concentrations of fibroblast growth factor 2, vascular endothelial growth factor and hepatocyte growth factor

PURPOSE

Some data have suggested that major surgery is associated with the post-operative growth of residual tumour masses but the mechanism of this is unknown. This study was designed to determine the relationship between intraperitoneal (IP) cytokine levels, and laparotomy in benign and malignant settings.

METHODS

Intraperitoneal fluid specimens were obtained at the start and at the end of laparotomy in patients with benign conditions (n=10) and in others undergoing resection of hepatic metastases from colorectal cancer (n=10). Using ELISA the concentration of the angiogenic cytokines, HGF, VEGF-A, VEGF-C, VEGF-D and FGF-2 was determined.

RESULTS

The data show that in 16 of 20 patients there was a significant increase (P=0.006) in the IP concentration of hepatocyte growth factor (HGF) but not in the other growth factors by the end of the operation. The mean increase in HGF concentration was 821.5 pg/ml (95% CI: 11.0-6,426.0). Neither the groups (malignant and non-malignant) nor the length of operation correlated with greater or lesser increases in HGF.

CONCLUSION

The observation that the increase in HGF occurred in both the cancer and non-cancer groups suggests that it is the surgery rather than the disease that is associated with the increased cytokine concentration. As HGF is a potent endothelial, epithelial and mesenchymal mitogen the data highlight HGF as a potential target for anti-cancer treatments in the peri-operative period. However, investigators should closely monitor wound healing as this may be compromised by this new class of drugs.

Phase III study of 5FU, etoposide and leucovorin (FELV) compared to epirubicin, cisplatin and 5FU (ECF) in previously untreated patients with advanced biliary cancer

The purpose of this study was to determine whether epirubicin, cisplatin and infused 5FU (ECF) improves overall survival (OS) compared to 5FU, etoposide and leucovorin (FELV) in patients with previously untreated advanced biliary cancer in a prospective randomised study. Patients were randomly assigned to receive epirubicin, cisplatin and infused 5FU ECF or bolus 5FU etoposide and leucovorin (FELV). The primary end point was OS with secondary end points of objective response rate (ORR), failure-free survival (FFS), quality of life (QOL) and toxicity. In all, 54 patients were recruited with 27 randomly assigned to each arm. The median OS for ECF was 9.02 months (95% confidence interval (CI): 6.46–11.51) and FELV 12.03 months (95% CI: 9.3–14.7), P=0.2059. Objective response rates were similar for both arms: ECF 19.2% (95% CI: 6.55–39.3); FELV 15% (95% CI: 3.2–37.9), P=0.72. There was significantly increased grade 3/4 neutropenia with FELV vs ECF (53.8 vs 29.5%, respectively, P=0.020). Symptom resolution was impressive for both regimens. This is the largest reported randomised study to date in this setting. ECF did not improve OS compared to FELV, but was associated with less acute toxicity. These data suggest that chemotherapy can prolong OS and achieve good symptomatic relief in advanced biliary cancer.

Phase II study of troxacitabine in chemotherapy-naïve patients with advanced cancer of the pancreas

BACKGROUND

Troxacitabine (Troxatyl) is a novel L-enantiomer nucleoside analog with activity in pancreatic cancer xenograft models.

PATIENTS AND METHODS

Troxacitabine 1.5 mg/m(2) was administered by 30-min infusions daily x5 every 4 weeks to 54 patients with advanced pancreatic cancer. Patients were evaluated for objective tumor response, time to tumor progression (TTP), changes in tumor marker CA 19-9, survival, safety, pain, analgesic consumption, Karnofsky performance status and weight change.

RESULTS

Median TTP was 3.5 months (95% CI 2.0-3.8), median survival 5.6 months (95% CI 4.9-7.4), and the 1 year survival rate 19%. Best responses were stable disease in 24 patients with eight patients having stable disease for at least 6 months (15%). A 50% or greater decrease in CA 19-9 was seen in seven of 44 assessed patients (16%). Grade 3 and 4 neutropenia were observed in 37% and 30% of patients with one episode of febrile neutropenia. The most common drug-related non-hematological toxic effects reported were cutaneous, with 22% and 6% of patients reporting grade 2 and 3 skin rash, respectively and 4% grade 2 hand-foot syndrome.

CONCLUSION

Troxacitabine administered by a bolus daily x5 monthly regimen has modest activity in advanced pancreatic adenocarcinoma.

Simulations in the United States Medical Licensing Examination (USMLE)

Over the last several years there has been much attention focused on the detection and remediation of problems that pose potential threats to patient safety and that interfere with the provision of effective care. It has been noted that changes in medical education and assessment are integral to eventual improvement in this area. Within the assessment system used to licence physicians in the United States, there has been an evolution of assessment formats intended to improve the measurement of knowledge and skills, including the recent development of computer based patient simulations and clinical skills assessments. A number of new testing formats intended to further enhance assessment of critical knowledge and skills will be available in the near future.

Simulations in the United States Medical Licensing Examination (USMLE)

Over the last several years there has been much attention focused on the detection and remediation of problems that pose potential threats to patient safety and that interfere with the provision of effective care. It has been noted that changes in medical education and assessment are integral to eventual improvement in this area. Within the assessment system used to licence physicians in the United States, there has been an evolution of assessment formats intended to improve the measurement of knowledge and skills, including the recent development of computer based patient simulations and clinical skills assessments. A number of new testing formats intended to further enhance assessment of critical knowledge and skills will be available in the near future.

T lymphocytes isolated from patients with advanced colorectal cancer are suitable for gene immunotherapy approaches

Despite improvements in treatment, the 5-year survival for metastatic colorectal cancer remains poor. Novel approaches such as gene immunotherapy are being investigated to improve treatment. Retroviral gene transfer methods have been shown to transduce primary human T lymphocytes effectively resulting in the expression of therapeutic genes. However, a number of defects have been identified in T lymphocytes isolated from patients bearing tumour, which may have critical implications for the development of gene-targeted T cells as an anticancer therapy. To address this issue, primary T lymphocytes were isolated from patients with advanced colorectal cancer and tested for their ability to be transduced and to express subsequently a chimeric immune receptor consisting of a single-chain antibody fragment antigen-binding moiety specific for carcinoembryonic antigen (CEA) fused to the T cell receptor (TCR) CD3zeta chain. In 10 out of 10 patients, T lymphocytes were transduced, expanded in the absence of selection and tested for functional activity against CEA-expressing tumour cells. In each case, functional-specific cytotoxic activity was observed. Negligible activity was found in control cultures. This study highlights the feasibility of patient-derived T lymphocytes as a source of immune cells for autologous gene immunotherapy approaches.

Targeted cytokine delivery to neuroblastoma

The aim of this study was to construct a fusion protein from the cytokine granulocyte/macrophage colony-stimulating factor (GM-CSF) and a single-chain Fv fragment (scFv D29) and to investigate its potential to activate cells of the immune system against neuroblastoma cells expressing neural cell adhesion molecule (NCAM). Mammalian cell expression of the scFv D29-GM-CSF fusion protein was compared using a number of vectors, including retroviral and adenoviral vectors. The resultant fusion protein, expressed by HeLa cells, was found by ELISA to bind immobilized recombinant NCAM. Moreover, FACS analysis confirmed binding to the human neuroblastoma cell line SKNBE and a murine neuroblastoma cell line engineered to express the glycosylphosphatidylinositol form of human NCAM (N2A-rKNIE). The fusion protein was also found to stimulate the proliferation of the FDC-P1 haemopoietic cell line, which is dependent on GM-CSF (or interleukin 3) for continued growth. In vitro clonogenic assays indicated that scFv-GM-CSF could selectively induce growth inhibition of SKNBE cells by murine lymphoid cells.

Marimastat as maintenance therapy for patients with advanced gastric cancer: a randomised trial

This randomised, double-blind, placebo-controlled study was designed to evaluate the ability of the orally administered matrix metalloproteinase inhibitor, marimastat, to prolong survival in patients with non-resectable gastric and gastro-oesophageal adenocarcinoma. Three hundred and sixty-nine patients with histological proof of adenocarcinoma, who had received no more than a single regimen of 5-fluorouracil-based chemotherapy, were randomised to receive either marimastat (10 mg b.d.) or placebo. Patients were treated for as long as was tolerable. The primary endpoint was overall survival with secondary endpoints of time to disease progression and quality of life. At the point of protocol-defined study completion (85% mortality in the placebo arm) there was a modest difference in survival in the intention-to-treat population in favour of marimastat (P=0.07 log-rank test, hazard ratio=1.23 (95% confidence interval 0.98-1.55)). This survival benefit was maintained over a further 2 years of follow-up (P=0.024, hazard ratio=1.27 (1.03-1.57)). The median survival was 138 days for placebo and 160 days for marimastat, with 2-year survival of 3% and 9% respectively. A significant survival benefit was identified at study completion in the pre-defined sub-group of 123 patients who had received prior chemotherapy (P=0.045, hazard ratio=1.53 (1.00-2.34)). This benefit increased with 2 years additional follow-up (P=0.006, hazard ratio=1.68 (1.16-2.44)), with 2-year survival of 5% and 18% respectively. Progression-free survival was also significantly longer for patients receiving marimastat compared to placebo (P=0.009, hazard ratio=1.32 (1.07-1.63)). Marimastat treatment was associated with the development of musculoskeletal pain and inflammation. Events of anaemia, abdominal pain, jaundice and weight loss were more common in the placebo arm. This is one of the first demonstrations of a therapeutic benefit for a matrix metalloproteinase inhibitor in cancer patients. The greatest benefit was observed in patients who had previously received chemotherapy. A further randomised study of marimastat in these patients is warranted.

Retroviral transduction of human peripheral blood lymphocytes with Bcl-X(L) promotes in vitro lymphocyte survival in pro-apoptotic conditions

The prolonged in vivo survival of genetically modified effector cells is crucial to the success of any (gene-modified) adoptive cellular immunotherapy approach. In cancer clinical trials to date, however, the detection of surviving circulating gene-modified T cells has required highly sensitive techniques. In vitro studies of T cell co-stimulation have shown that up-regulation of the anti-apoptosis gene Bcl-X(L) by ligation of CD28 promotes T cell survival, but not proliferation. Here we have investigated the ability to modulate resistance to apoptosis and improve cell survival by transducing human peripheral blood lymphocytes using a retroviral vector that expresses Bcl-X(L). We show that Jurkat cells transduced with Bcl-X(L) retrovirus were partially resistant to Fas (CD95) antibody-induced apoptosis. Subsequent in vitro assays with transduced primary human lymphocytes demonstrates that over-expression of Bcl-X(L) promotes the survival of lymphocytes cultured in the absence of interleukin-2. Activation-induced apoptosis with anti-CD3(epsilon) antibody, OKT3 is also modulated. Furthermore, Bcl-X(L) over-expression in human lymphocytes delays the onset of apoptosis induced by long-term co-culture with tumour cell lines. Despite this improved in vitro survival, in a preliminary experiment to assess safety, no signs of malignancy or autoimmunity were observed in NOD/SCID mice injected with Bcl-X(L) transduced lymphocytes. These results indicate that expression of Bcl-X(L) in lymphocyte therapy either alone or in conjunction with an additional therapeutic gene could enhance persistence of cells in vivo thereby potentially improving the clinical outcome of adoptive cellular therapy.

Cimetidine in colorectal cancer--are the effects immunological or adhesion-mediated?

British Journal of Cancer (2002) 86, 159–160. DOI: 10.1038/sj/bjc/6600097www.bjcancer.com

© 2002 The Cancer Research Campaign

Vaccines in oncology: background and clinical potential

Cancer is one of the leading causes of death in Western society. Despite improvements in screening, diagnosis and treatment of cancer, many patients ultimately succumb to their disease. Advances in molecular biology and our increased understanding of how the immune system functions have led to an intense interest in the development of cancer vaccines.

Targeting of adenovirus to endothelial cells by a bispecific single-chain diabody directed against the adenovirus fiber knob domain and human endoglin (CD105)

The use of adenoviruses for antivascular cancer gene therapy is limited by their low transduction efficiency for endothelial cells. We have developed a recombinant bispecific antibody as a molecular bridge, linking the adenovirus capsid to the endothelial cell surface protein endoglin, for vascular targeting of adenoviruses. Endoglin (CD105), a component of the transforming growth factor beta receptor complex, represents a promising target for antivascular cancer therapy. Endoglin is expressed predominantly on endothelial cells and is upregulated in angiogenic areas of tumors. We isolated single-chain Fv fragments directed against human endoglin from a human semisynthetic antibody library. One of the isolated scFv fragments (scFv C4) bound specifically to various proliferating primary endothelial cells or cell lines including HUVEC, HDMEC, HMVEC, and HMEC. ScFv C4 was therefore used to construct a bispecific single-chain diabody directed against endoglin and the adenovirus fiber knob domain (scDb EDG-Ad). This bispecific molecule mediated enhanced and selective adenovirus transduction of HUVECs, which was independent from binding to the coxsackievirus and adenovirus receptor (CAR) and alpha(v)-integrins. Thus, adenovirus infection was redirected to a new cellular receptor (CD105) and cell entry pathway. These results demonstrate the utility of bispecific single-chain diabodies, which can be produced in large quantities in bacteria, for the retargeting of adenoviruses in cancer gene therapy.

Selective targeting of gene transfer to vascular endothelial cells by use of peptides isolated by phage display

BACKGROUND

Gene transfer to vascular cells is a highly inefficient and nonselective process, defined by the lack of specific cell-surface receptors for both nonviral and viral gene delivery vectors.

METHODS AND RESULTS

We used filamentous phage display to isolate a panel of peptides that have the ability to bind selectively and efficiently to quiescent human umbilical vein endothelial cells (HUVECs) with reduced or negligible binding to nonendothelial cells, including vascular smooth muscle cells and hepatocytes. By direct biopanning on HUVECs and a second approach involving preclearing steps before panning on HUVECs, we isolated and sequenced 140 individual phages and identified 59 peptides. We selected 7 candidates for further investigation by secondary screening of homogeneous phages on a panel of cell types. Using adenovirus-mediated gene transfer as a model gene delivery system, we cloned the peptide SIGYPLP and the positive control peptide KKKKKKK upstream of the S11e single-chain Fv ("adenobody") directed against the knob domain of the adenovirus to create fusion proteins. Adenovirus-mediated gene transfer via fiber-dependent infection was blocked with S11e, whereas inclusion of the KKKKKKK peptide retargeted gene transfer. The peptide SIGYPLP, however, retargeted gene delivery specifically to endothelial cells with a significantly enhanced efficiency over nontargeted adenovirus and without transduction of nontarget cells.

CONCLUSIONS

Our study demonstrates the feasibility of using small, novel peptides isolated via phage display to target gene delivery specifically and efficiently to HUVECs and highlights their use for retargeting both viral and nonviral gene transfer to vascular endothelial cells for future clinical applications.

Increased cell survival by inhibition of BRCA1 using an antisense approach in an estrogen responsive ovarian carcinoma cell line

STATEMENT OF FINDINGS: We tested the hypothesis that BRCA1 may play a role in the regulation of ovarian tumor cell death as well as the inhibition of ovarian cell proliferation. Introduction of BRCA1 antisense retroviral constructs into BG-1 estrogen-dependent ovarian adenocarcinoma cells resulted in reduced BRCA1 expression. BRCA1 antisense pooled populations and derived subclones were able to proliferate in monolayer culture without estrogen, whereas control cells began to die after 10 days of estrogen deprivation. In addition, both populations and subclones of BRCA1 antisense infected cells demonstrated a growth advantage in monolayer culture in the presence of estrogen and were able to proliferate in monolayer culture without estrogen, while control cells did not. Furthermore, clonal studies demonstrated that reduced levels of BRCA1 protein correlated with growth in soft agar and greater tumor formation in nude mice in the absence of estrogen. These data suggest that reduction of BRCA1 protein in BG-1 ovarian adenocarcinoma cells may have an effect on cell survival during estrogen deprivation both in vitro and in vivo.

The in-training examination in internal medicine: resident perceptions and lack of correlation between resident scores and faculty predictions of resident performance

PURPOSE

We sought to survey residents' perceptions regarding the In-Training Examination in Internal Medicine and to assess the ability of faculty members to evaluate the knowledge base of internal medicine residents.

SUBJECTS AND METHODS

Residents were asked about the perceived utility of the In-Training Examination and related self-directed educational activities. Residents predicted their own performance on the examination (into upper, middle, or lower tertile). Faculty predicted housestaffs scores, and residents predicted the scores of interns.

RESULTS

Most residents (35/36; 97%) believed that the examination was useful, and 91% modified their study habits or clinical rotation schedule based on its results. Approximately half of the residents accurately predicted into which tertile they would score. Faculty predictions of resident performance on the examination were accurate 49% of the time, and resident predictions of intern scores were accurate 38% of the time. The sensitivity ofa lower-tertile prediction by faculty was 34%, with a specificity of 90%. The sensitivity of a resident prediction of a lower-tertile intern score was 15%, with a specificity of 98%. Both faculty and residents were more likely to overestimate than underestimate examination scores.

CONCLUSION

Residents believe that the In-Training Examination is useful and frequently initiate educational interventions based on results. Faculty and residents lack the ability to evaluate accurately the knowledge of trainees that they supervise. In particular, both groups may be unable to identify trainees who are deficient in this element of clinical competence.

Methods for evaluating the clinical competence of residents in internal medicine: a review

This paper reviews methods commonly used to assess the clinical competence of residents in internal medicine, including the In-Training Examination, medical record audits, rating scales, clinical evaluation exercises, and the use of standardized patients. Studies were identified through a MEDLINE search (1966 to present) and from the bibliographies of relevant articles and were selected for inclusion according to consensus between the authors. Whenever possible, original studies were chosen over reviews and editorials. No single assessment method can successfully evaluate the clinical competence of residents in internal medicine, and educators need to be cognizant of the most appropriate applications and the advantages and disadvantages of the available evaluation tools. A combination of assessment tools provides the best opportunity to evaluate and educate physicians-in-training.

Recombinant adenoviral delivery for in vivo expression of scFv antibody fusion proteins

Antibodies and their recombinant fragments have enormous potential for therapy of malignant and other diseases, but there can be problems associated with their production and purification in the quantities required for therapeutic use. We investigated the use of gene therapy for the production of such recombinant antibody fragments in vivo. We generated two recombinant adenoviruses expressing the single chain Fvs (scFvs) fused to murine GM-CSF (mGM-CSF). The scFvs used are MFE-23 which binds to a human tumour-associated marker carcino-embryonic antigen (CEA) and B1.8 which binds the hapten 4-hydroxy-3-nitro-5-iodo-phenylacetyl (NIP). Using scFvs to target GM-CSF to tumour cells should reduce the systemic toxicity of GM-CSF but retain its ability as a cytokine to induce systemic immune responses to tumour targets. Cell lines infected with the recombinant adenoviruses in vitro express and secrete high levels of the scFv.mGM-CSF fusion proteins. The scFv retains specificity while the mGM-CSF portion is fully bioactive and there is no detectable degradation of the fusion product. We also demonstrated effective in vivo expression of the scFv.mGM-CSF proteins. C57BI/6 mice injected intravenously with the adenovirus encoding the MFE-23.mGM-CSF fusion produce high levels of the fusion protein by 2 days after infection. The scFv.mGM-CSF protein can be detected in the serum, at biologically active levels, for at least 20 days and the level of protein produced is related to the amount of adenovirus injected. This approach has the potential to streamline the testing of the many therapeutic strategies based on recombinant scFvs and we are currently testing these constructs in an animal model for antitumour activity.

Efficient transgene regulation from a single tetracycline-controlled positive feedback regulatory system

Control of gene expression in eukaryotic cells is clearly important in many applications including modifications of the level of a therapeutic gene product. For effective gene delivery and regulation, the regulatory system must be contained on a single vector and it must exhibit high transgene expression on induction and low basal expression on repression. Here, we have investigated several self-contained vectors carrying both the tetracycline-controlled transactivator (tTA) and a potentially therapeutic gene in transient studies. An enhancerless positive feedback regulatory vector (pSiaIV) transcribing both tTA and mGM-CSF from a modified tTA-responsive bidirectional promoter demonstrated over 200-fold gene regulation in HeLa cells. This was comparable to the degree of regulation obtained on cotransfection of vectors expressing tTA and tTA-responsive mGM-CSF. The maximal transcriptional activity of pSiaIV was comparable to that of CMV IE promoter and its basal activity as low as the leakiness of the tetracycline-responsive promoter (tRP) in several commonly used cell lines, resulting in 47- to 328-fold regulation. Furthermore, pSiaIV also showed efficient regulation in stable cells. Overall, the positive feedback regulatory system (PFRS) offers efficient gene regulation which is suitable for most applications, especially gene therapy.

Pharmacological control of antigen responsiveness in genetically modified T lymphocytes

A chimeric TCR gene, comprising an anti-hapten single-chain Ab variable fragment fused to the transmembrane and cytoplasmic regions of the human TCR zeta-chain, was used to determine whether the tetracycline-regulatable system could be used to regulate gene expression in T cells. Jurkat T cells were stably transfected with a single vector encoding the tetracycline trans-activator protein, controlled by a constitutive promoter, and the chimeric TCR, under the control of a trans-activator protein-responsive promoter. In the absence of tetracyclines, the transfected T cells were shown to express the chimeric receptor on the cell surface and could be activated by its cognate Ag, leading to the secretion of IL-2. When the cells were exposed to increasing concentrations of tetracyclines, surface expression of the chimeric receptor was suppressed in a dose-dependent manner, and this suppression was sufficient to result in complete loss of responsiveness to the targeted Ag. Prolonged suppression of trans-gene expression for up to 7 days was observed after doxycycline was removed from the cultures, but eventual recovery of surface expression was complete, and the absolute time to recovery was directly proportional to the initial concentration of the drug. Pharmacologic control of trans-gene expression in gene-modified T cells will not only facilitate new approaches to the study of different aspects of T cell biology, but will also provide the basis for new gene therapy strategies.

Pharmacological control of antigen responsiveness in genetically modified T lymphocytes

A chimeric TCR gene, comprising an anti-hapten single-chain Ab variable fragment fused to the transmembrane and cytoplasmic regions of the human TCR zeta-chain, was used to determine whether the tetracycline-regulatable system could be used to regulate gene expression in T cells. Jurkat T cells were stably transfected with a single vector encoding the tetracycline trans-activator protein, controlled by a constitutive promoter, and the chimeric TCR, under the control of a trans-activator protein-responsive promoter. In the absence of tetracyclines, the transfected T cells were shown to express the chimeric receptor on the cell surface and could be activated by its cognate Ag, leading to the secretion of IL-2. When the cells were exposed to increasing concentrations of tetracyclines, surface expression of the chimeric receptor was suppressed in a dose-dependent manner, and this suppression was sufficient to result in complete loss of responsiveness to the targeted Ag. Prolonged suppression of trans-gene expression for up to 7 days was observed after doxycycline was removed from the cultures, but eventual recovery of surface expression was complete, and the absolute time to recovery was directly proportional to the initial concentration of the drug. Pharmacologic control of trans-gene expression in gene-modified T cells will not only facilitate new approaches to the study of different aspects of T cell biology, but will also provide the basis for new gene therapy strategies.

Abdominal vascular catastrophes

Abdominal vascular catastrophes are due to rupture of arterial aneurysms or arterial occlusion leading to end organ ischemia. In this article, we will discuss rupture of abdominal aortic aneurysms and visceral artery aneurysms. Arterial occlusion secondary to embolism, thrombosis and dissection will be presented. Mesenteric ischemia secondary to low flow states, venous thrombosis and other conditions will also be covered. These uncommon, but frequently fatal pathological processes, are of interest to both general and vascular surgeons.

The 'adenobody' approach to viral targeting: specific and enhanced adenoviral gene delivery

Recombinant adenoviruses have enormous potential as vectors for gene therapy. They have evolved an efficient method of infection and a wide host range but this leads to concerns about the specificity of gene delivery. In order to target an adenovirus type 5-based vector we have investigated an antibody approach. A virus neutralising scFv antibody fragment was isolated from a phage library and a C-terminal fusion protein with epidermal growth factor (EGF) constructed. This fusion protein, or 'adenobody', bound both to the fibre protein of the adenovirus and to the EGF receptor (EGFR) on human cells, and was able to direct adenoviral binding to the new receptor. Using this system the efficiency of viral infection was markedly enhanced and was targeted to the EGFR. The adenobody-directed infection correlated with the level of EGF receptor expressed on the cells and could be blocked by competition with pure EGF. Peptide inhibition experiments suggest that infection is mediated directly through attachment to the EGFR and does not require penton-integrin interactions. This work shows that the 'adenobody' approach can enhance the efficiency as well as target adenoviral infection and has numerous potential applications for gene therapy.

Delay in resumption of the activity of tetracycline-regulatable promoter following removal of tetracycline analogues

The tetracycline-regulatable system (TRS) has become a widely adopted tool for modification of gene expression and analysis of gene function in mammalian cells, plants and transgenic animals. We have studied the potential application of the TRS in gene therapy, using a single vector containing both the tetracycline-controlled transactivator (tTA) and the tTA-responsive promoter (tRP) transcribing mouse GM-CSF. Stable 293 cells established using this vector were used to study the kinetics of the TRS in response to various tetracycline analogues. Dose-response studies show that doxycycline is the most potent-analogue in abolishing tTA activity. Kinetic studies indicate that, at 1,000 ng/ml, all the analogues have similar efficiencies in down-regulating the system in given time. In contrast, following the removal of the analogues, there is a temporal, dose-dependent delay in resumption of the tRP activity. The time taken for resumption of near-optimal tRP activity is approximately 48 h for tetracycline, 144 h for anhydrotetracycline, 192 h for minocycline and 216 h for doxycycline when cells were pretreated with 1000 ng/ml of these antibiotics. This property of the analogues can be employed in planning a desired course of transgene regulation.

Antigen-specific targeting of CD28-mediated T cell co-stimulation using chimeric single-chain antibody variable fragment-CD28 receptors

T cells require two distinct signals for optimal activation. One is an antigen-specific signal and is provided by engagement of the T cell receptor (TCR). The second is an antigen-independent signal mediated by engagement of the T cell surface molecule CD28 with members of the B7 family. To endow CD28 molecules with antibody-type recognition, we have constructed chimeric single-chain antibody variable fragment (scFv)-CD28 molecules; following transfection of the genes encoding such constructs into the Jurkat human T cell line we show that they are stably expressed as functional cell surface receptors. These chimeric molecules have no apparent negative effects on the expression and signaling ability of the wild-type CD28 and TCR/CD3 molecules. When combined with signaling via the TCR/CD3 complex, these antigen-specific scFv-CD28 chimeric molecules provide signals similar to those elicited by the cross-linking of the unmodified CD28 molecules. Furthermore, the generation of double transfectants simultaneously expressing scFv-CD28 and scFv-CD3 zeta chimeras demonstrates that antigen-specific co-stimulatory signals can also synergize with signals mediated through chimeric CD3 zeta chains to secrete maximal levels of interleukin-2. Overall, our results suggest that optimal, predefined antigen-specific activation of T cells directed by the specificity of the scFv should be possible.

Clinical evidence of efficient tumor targeting based on single-chain Fv antibody selected from a combinatorial library

We present a system for cancer targeting based on single-chain Fv (scFv) antibodies selected from combinatorial libraries, produced in bacteria and purified by using an engineered tag. Combinatorial libraries of scFv genes contain great diversity, and scFv antibodies with characteristics optimized for a particular task can be selected from them using filamentous bacteriophage. We illustrate the benefits of this system by imaging patients with carcinoembryonic antigen (CEA)-producing cancers using an iodine-123 labeled scFv anti-CEA selected for high affinity. All known tumor deposits were located, and advantages over current imaging technology are illustrated. ScFvs are produced in a cloned form and can be readily engineered to have localizing and therapeutic functions that will be applicable in cancer and other diseases.

Technetium-99m radiolabeling using a phage-derived single-chain Fv with a C-terminal cysteine

Single-chain Fv (scFv) antibody fragments have potential for clinical imaging because of their rapid tumor penetration and high tumor-to-tissue ratios at early time points. ScFvs clear rapidly from the circulation so radiolabels such as 99mTc which have short half-lives are desirable, but the free thiol groups necessary for labeling with 99mTc are not normally found on these molecules.

METHODS

We constructed a vector which enabled a free cysteine to be linked to the C-terminus of scFvs. MFE-23, a scFv directed against carcinoembryonic antigen (CEA), was cloned into this vector and cys-tagged MFE-23 was labeled with 99mTc using a D-glucarate transfer method.

RESULTS

The radiolabeled product was stable in vivo and in vitro and showed favorable tumor-to-blood ratios in vivo at early time points (4:1 at 24 hr and 8:1 at 48 hr), although high kidney levels were also detected.

CONCLUSION

Our study demonstrates an effective method to enable scFvs radiolabeling with 99mTc and also shows the potential of using a 99mTc-labeled scFv for clinical imaging studies.

A genetic approach to idiotypic vaccination for B cell lymphoma

Idiotypic immunoglobulin expressed by a B cell tumor presents a clear tumor antigen which could be attacked by vaccination of the host. Vaccination with idiotypic protein has been shown to induce protective immunity against lymphoma, but application to patients is limited by the requirement of "personal" vaccines for each patient. A genetic approach enables V-region sequences encoding idiotypic antigen to be rescued from tumor biopsies, and to be assembled as scFv fragments. These can be expressed in bacteria to produce recombinant protein, or used directly as naked DNA vaccines. Intramuscular injection of idiotypic DNA from a mouse B cell lymphoma induces low levels of syngeneic anti-idiotypic antibody in serum. Response can be stimulated by co-injection of DNA plasmids encoding either IL-2 or GM-CSF, and T cells which proliferate in response to idiotypic IgM are generated. However, protection against tumor appears to be blocked by continuing secretion of idiotypic antigen from the persisting vaccine vector, which forms immune complexes with serum antibody. Methods for regulating the level of scFv to engage the immune system, but not to block the effector arm are being investigated. Similar control will be applicable to the cytokine vectors, which can deliver encoded cytokines designed to activate immune pathways for tumor destruction. Experience gained in lymphoma may be extended to other tumors with defined tumor antigens.

Clinical issues in antibody design

Antibody genes can now be cloned and expressed in various ways to give new versions of antibodies that possess reduced immunogenicity, improved affinity, altered size, increased avidity and novel effector functions. The task for any clinical application is, first, to define a relevant target, and then to design the optimal antibody-based therapeutic molecule to react with that target. This article reviews these improved antibody-based molecules and examines their role in cancer therapy.