In vivo magnetic resonance imaging and spectroscopy identifies oncolytic adenovirus responders

At present, it is not possible to reliably identify patients who will benefit from oncolytic virus treatments. Conventional modalities such as computed tomography (CT), which measure tumor size, are unreliable owing to inflammation-induced tumor swelling. We hypothesized that magnetic resonance imaging (MRI) and spectroscopy (MRS) might be useful in this regard. However, little previous data exist and neither oncolytic adenovirus nor immunocompetent models have been assessed by MRS. Here, we provide evidence that in T2-weighted MRI a hypointense core area, consistent with coagulative necrosis, develops in immunocompetent Syrian hamster carcinomas that respond to oncolytic adenovirus treatment. The same phenomenon was observed in a neuroblastoma patient while he responded to the treatment. With relapse at a later stage, however, the tumor of this patient became moderately hyperintense. We found that MRS of taurine, choline and unsaturated fatty acids can be useful early indicators of response and provide detailed information about tumor growth and degeneration. In hamsters, calprotectin-positive inflammatory cells (heterophils and macrophages) were found in abundance; particularly surrounding necrotic areas in carcinomas and T cells were significantly increased in sarcomas, when these had been treated with a granulocyte-macrophage colony-stimulating factor-producing virus, suggesting a possible link between oncolysis, necrosis (seen as a hypointense core in MRI) and/or immune response. Our study indicates that both MRI and MRS could be useful in the estimation of oncolytic adenovirus efficacy at early time points after treatment.

CD40 ligand and tdTomato-armed vaccinia virus for induction of antitumor immune response and tumor imaging

Oncolytic vaccinia virus is an attractive platform for immunotherapy. Oncolysis releases tumor antigens and provides co-stimulatory danger signals. However, arming the virus can improve efficacy further. CD40 ligand (CD40L, CD154) can induce apoptosis of tumor cells and it also triggers several immune mechanisms. One of these is a T-helper type 1 (Th1) response that leads to activation of cytotoxic T-cells and reduction of immune suppression. Therefore, we constructed an oncolytic vaccinia virus expressing hCD40L (vvdd-hCD40L-tdTomato), which in addition features a cDNA expressing the tdTomato fluorochrome for detection of virus, potentially important for biosafety evaluation. We show effective expression of functional CD40L both in vitro and in vivo. In a xenograft model of bladder carcinoma sensitive to CD40L treatment, we show that growth of tumors was significantly inhibited by the oncolysis and apoptosis following both intravenous and intratumoral administration. In a CD40-negative model, CD40L expression did not add potency to vaccinia oncolysis. Tumors treated with vvdd-mCD40L-tdtomato showed enhanced efficacy in a syngenic mouse model and induced recruitment of antigen-presenting cells and lymphocytes at the tumor site. In summary, oncolytic vaccinia virus coding for CD40L mediates multiple antitumor effects including oncolysis, apoptosis and induction of Th1 type T-cell responses.

Time trends in survival from cancer of unknown primary: small steps forward

BACKGROUND

Cancer of unknown primary (CUP) is a fatal cancer for which incidence trends have changed but detailed survival trends remain unexplored. These could point out successful diagnostic and therapeutic approaches. We investigate survival trends in CUP according to histology, locations of metastases and site-specific causes of death.

PATIENTS AND METHODS

A total of 20,523 CUP patients with nodal and extranodal metastases were identified from the Swedish Cancer Registry. Hazard ratios (HRs) were estimated, comparing three different time periods (1987-1993, 1994-2000 and 2001-2008) with respect to histological subtype, CUP location and the cause of death.

RESULTS

Survival for patients with CUP increased over the study period (HR=0.91 [95% confidence interval (CI): 0.78-0.84], p<0.001 for trend). Adenocarcinoma was the only histology associated with increased survival (0.78 [0.74-0.82], p<0.001 for trend). Survival was improved most clearly for CUP of the pelvis (0.55 [0.36-0.83]), peritoneum (0.58 [0.53-0.65]) and nervous system (0.46 [0.29-0.72]). Survival improved substantially in patients with ovarian (0.57 [0.46-0.70]), peritoneal (0.39 [0.24-0.65]) and biliary system cancers (0.67 [0.52-0.87]). Kaplan-Meier curves showed significant survival gains for all CUP and adenocarcinoma patients (p<0.001).

CONCLUSIONS

Over time, survival for patients with CUP increased for adenocarcinoma and for CUP of the pelvis, peritoneum and nervous system. Survival trends in CUP may be related to (1) similar trends in other common metastatic tumours, particularly pancreatic and hepatobiliary cancers, which are common 'hidden' primaries for CUP, (2) earlier detection and (3) advances in the management of metastatic cancers. The improvement in survival at specific locations suggests true therapeutic gains.

Site-specific cancer deaths in cancer of unknown primary diagnosed with lymph node metastasis may reveal hidden primaries

Cancer of unknown primary site (CUP) is a fatal cancer ranking among the five most common cancer deaths. CUP is diagnosed through metastases, which are limited to lymph nodes in some patients. Cause-specific survival data could guide the search for hidden primary tumors and help with therapeutic choices. The CUP patients were identified from the Swedish Cancer Registry between 1987 and 2008; 1,444 patients had only lymph node metastasis of defined histology (adenocarcinoma, squamous cell or undifferentiated). Site-specific cancer deaths were analyzed by lymph node location and histology. Kaplan-Meier survival curves were compared with metastatic primary cancer at related sites. Among the patients with metastasis to head and neck lymph nodes, 117 (59.1% of the specific cancer deaths) died of lung tumors. Patients with axillary lymph node metastasis died of lung and breast tumors in equal proportions (40.2% each). Also, squamous cell CUP in head and neck lymph nodes was mainly associated with lung tumor deaths (53.1%). With a few exceptions, survival of CUP patients with lymph node metastasis was indistinguishable from survival of patients with metastatic primary cancer originating from the organs drained by those nodes. The association between lymph node CUP metastases with cancer deaths in the drained organ and the superimposable survival kinetics suggests that drained organs host hidden primaries. Importantly, half of all site-specific cancer deaths (266/530) were due to lung tumors. Thus, an intense search should be mounted to find lung cancer in CUP patients with lymph node metastases.

Cancer of unknown primary (CUP): does cause of death and family history implicate hidden phenotypically changed primaries?

BACKGROUND

Cancer of unknown primary (CUP) is diagnosed at the metastatic stage. We aimed to identify hidden primary cancers in CUP patients by comparison with cancers in family members. We take use of the fact that the cause of death in CUP patients is often coded as the cancer in the organ of fatal metastasis.

PATIENTS AND METHODS

Forty-one thousand five hundred and twenty-three CUP patients were identified in the Swedish Family-Cancer Database, and relative risks (RRs) were calculated for cancer in offspring when family members were diagnosed with CUP and died of the cancer diagnosed in offspring.

RESULTS

The RR for lung cancer in offspring was 1.85 when a family member was diagnosed with CUP and died of lung cancer. Significant familial associations were found for seven other cancers. Many familial associations were also significant when offspring CUP patients died of the cancer diagnosed in family members.

CONCLUSIONS

The cause of death after CUP diagnosis frequently matched the cancer found in a family member, suggesting that the CUP had originated in that tissue. The metastasis had probably undergone a phenotypic change, complicating pathological tissue assignment. These novel data suggest that some CUP cases are phenotypically modified primary cancers rather than cancers of unknown primaries.

Survival in cancer of unknown primary site: population-based analysis by site and histology

BACKGROUND

Cancer of unknown primary (CUP) is diagnosed at a metastatic stage, conferring an unfavorable prognosis. The natural history of the disease is poorly understood, which complicates diagnosis, treatment and follow-up. Population-based survival data are lacking regarding location and histology of metastases.

PATIENTS AND METHODS

From the Swedish Cancer Registry, 18 911 CUP patients were identified between years 1987 and 2008. Survival was analyzed by Kaplan-Meier survival curves and Cox regression.

RESULTS

Adenocarcinoma accounted for 70% of all extranodal cases with a 12-month survival of 17% and the median survival of 3 months. Adenocarcinoma was also the most common histology (33.4%) when metastases were limited to lymph nodes, with a 12-month survival of 41% and median survival of 8 months. For extranodal metastases, the extremes in survival were small intestinal cancer with poor prognosis and mediastinal cancer with favorable prognosis. For nodal metastases, patients affected in the head and neck, axillary and inguinal regions had the best prognosis and those with abdominal and intrapelvic metastases the worst prognosis.

CONCLUSIONS

The present data underline the importance of histology and location of metastasis in assisting clinical decision making: hazard ratios differed by a factor of five among extranodal and nodal metastases.

Macrophage metalloelastase (MME) as adjuvant for intra-tumoral injection of oncolytic adenovirus and its influence on metastases development

Oncolytic adenoviruses are a promising treatment alternative for many advanced cancers, including colorectal cancer. However, clinical trials have demonstrated that single-agent therapy in advanced tumor masses is rarely curative. Poor spreading of the virus through tumor tissue is one of the major issues limiting efficacy. As oncolytic viruses kill preferentially cancer cells, high extracellular matrix (ECM) content constitutes potential barriers for viral penetration within tumors. In this study, the ECM-degrading proteases relaxin, hyaluronidase, elastase and macrophage metalloelastase (MME) were tested for their antitumor efficacy alone and in combination with oncolytic adenovirus. MME improved the overall antitumor efficacy of oncolytic adenovirus in subcutaneous HCT116 xenografts. In a liver metastatic colorectal cancer model, intra-tumoral treatment of primary tumors from HT29 cells with MME monotherapy or with oncolytic adenovirus inhibited tumor growth. Combination therapy showed no increased mortality in comparison with either monotherapy alone. Contradictory results of effects of MME on tumorigenesis and metastasis formation have been reported in the literature. This study demonstrates for the first time in a metastatic animal model that MME, as a monotherapy or in combination with oncolytic virus, does not increase tumor invasiveness. Co-administration of MME and oncolytic adenovirus may be a suitable approach for further optimization aiming at clinical applications for metastatic colorectal cancer.

Oncolytic adenovirus based on serotype 3

Oncolytic adenoviruses have been safe in clinical trials but the efficacy has been mostly limited. All published trials have been performed with serotype 5 based viruses. The expression level of the Ad5 receptor CAR may be variable in advanced tumors. In contrast, the Ad3 receptor remains unclear, but is known to be abundantly expressed in most tumors. Therefore, we hypothesized that a fully serotype 3 oncolytic adenovirus might be useful for treating cancer. Patients exposed to adenoviruses develop high titers of serotype-specific neutralizing antibodies, which might compromise re-administration. Thus, having different serotype oncolytic viruses available might facilitate repeated dosing in humans. Ad3-hTERT-E1A is a fully serotype 3 oncolytic adenovirus controlled by the promoter of the catalytic domain of human telomerase. It was effective in vitro on cell lines representing seven major cancer types, although low toxicity was seen in non-malignant cells. In vivo, the virus had anti-tumor efficacy in three different animal models. Although in vitro oncolysis mediated by Ad3-hTERT-E1A and wild-type Ad3 occurred more slowly than with Ad5 or Ad5/3 (Ad3 fiber knob in Ad5) based viruses, in vivo the virus was at least as potent as controls. Anti-tumor efficacy was retained in presence of neutralizing anti-Ad5 antibodies whereas Ad5 based controls were blocked. In summary, we report generation of a non-Ad5 based oncolytic adenovirus, which might be useful for testing in cancer patients, especially in the context of high anti-Ad5 neutralizing antibodies.

Prolonged systemic circulation of chimeric oncolytic adenovirus Ad5/3-Cox2L-D24 in patients with metastatic and refractory solid tumors

Eighteen patients with refractory and progressive solid tumors were treated with a single round of triple modified oncolytic adenovirus (Ad5/3-Cox2L-D24). Ad5/3-Cox2L-D24 is the first non-Coxsackie-adenovirus receptor-binding oncolytic adenovirus used in humans. Grades 1-2 flu-like symptoms, fever, and fatigue were seen in most patients, whereas transaminitis or thrombocytopenia were seen in some. Non-hematological grades 3-5 side effects were seen in one patient with grade 3 ileus. Treatment resulted in high neutralizing antibody titers within 3 weeks. Virus appeared in serum 2-4 days after treatment in 83% of patients and persisted for up to 5 weeks. One out of five radiologically evaluable patients had partial response (PR), one had minor response (MR), and three had progressive disease (PD). Two patients scored as PD had a decrease in tumor density. Tumor reductions not measurable with Response Evaluation Criteria In Solid Tumors (RECIST) were seen in a further four patients. PR, MR, stable disease, and PD were seen in 12, 23.5, 35, and 29.5% of tumor markers analyzed, respectively (N=17). Ad5/3-Cox2L-D24 appears safe for treatment of cancer in humans and extended virus circulation results from a single treatment. Objective evidence of anti-tumor activity was seen in 11/18 (61%) of patients. Clinical trials are needed to extend these findings.

Cancer gene therapy with oncolytic adenoviruses

Metastatic cancer remains difficult to treat effectively and treatments are in most cases not curative despite significant side effects. Novel, targeted approaches such as gene therapy hold promise for the treatment of various tumor types. Among the most promising cancer gene therapy approaches are oncolytic adenoviruses, which are able to infect, replicate in and lyse tumor cells. Recent data from clinical trials with these vectors have shown that they are safe. However, antitumor efficacy needs to be improved to make oncolytic adenoviruses a viable treatment alternative for cancer patients. This review focuses on targeting strategies to improve tumor cell transduction and cancer cell selective replication. Strategies to improve antitumor efficacy by arming the virus with therapeutic transgenes are also discussed. Furthermore, an overview of the most important clinical approaches with oncolytic adenoviruses is given.

A phase I/II trial of gefitinib given concurrently with radiotherapy in patients with nonmetastatic prostate cancer

e16079

Background: We estimated the safety and tolerability of 250 mg gefitinib q.d. given concurrently with three- dimensional conformal radiotherapy (3D-CRT) in patients with non-metastatic prostate cancer (PC). Methods: 42 patients with T2/T3N0M0 PC were treated in a single centre, non-randomized study (study code ZD1839/IL0118). PSA<20 and good performance status (WHO 0–1) were required. Adjuvant or neo-adjuvant hormonal treatments were not allowed. 250 mg gefitinib q.d. was started one week before and lasted for the duration of radiation therapy. 50.4 Gy (1.8 Gy/day) of 3D-CRT was administered to the tumor, prostate and seminal vesicles, followed by a 22 Gy booster (2 Gy/day) for a 72.4 Gy total dose. EGFR expression, presence of EGFRvIII and activated pEGFR were studied. Levels of serum TNF, IL-1 α and IL-6 were also evaluated. Results: Maximum tolerated dose was not reached in phase I (12 patients) and 30 additional patients were treated in phase II. Thirty (71.4%) patients completed trial medication and 12 (28.6%) prematurely discontinued because of adverse events. Dose-limiting toxicities were recorded in 16 (38.1%) patients, the most common of which was grade 3–4 transaminase increase (6 patients). After median follow-up of 38 months nobody had died of PC. The estimated PSA-free survival rate at 4 years (Kaplan-Meier) was 97%, hormone-free survival 91% and overall survival 87%. These figures compared favourably with matched, non-randomized patients treated with radiation only. Data on biochemical analyses will be presented. Conclusions: The combination of gefitinib and radiation is reasonably well tolerated and has promising activity in non-metastatic PC. A randomized study is being discussed for evaluating the efficacy of the approach.

[Table: see text]

Extended release of adenovirus from silica implants in vitro and in vivo

Despite promising preclinical results, the clinical benefits of cancer gene therapy have been modest heretofore. The main obstacle continues to be the level and persistence of gene delivery to sufficiently large areas of the tumor. One approach for overcoming this might entail extended local virus release. We studied the utility of silica gel monoliths for delivery of adenovirus to advanced orthotopic gastric and pancreatic cancer tumors. Initially, the biochemical properties of the silica-virus matrix were studied and nearly linear release as a function of time was detected. Virus stayed infective for weeks at +37 degrees C and months at +4 degrees C, which may facilitate storage and distribution. In vivo, extended release of functional replication deficient and also replication-competent, capsid-modified oncolytic viruses was seen. Treatment of mice with pancreatic cancer doubled their survival (P<0.001). Also, silica gel-based delivery slowed the development of antiadenovirus antibodies.

Changing the adenovirus fiber for retaining gene delivery efficacy in the presence of neutralizing antibodies

Prior infection has primed most adult humans for a rapid neutralizing antibody (NAb) response when re-exposed to adenovirus. NAb induction can severely limit the efficacy of systemic re-administration of adenoviral gene therapy. We hypothesized that changing the fiber knob could overcome NAb. Immune-competent mice were exposed to serotype 5 adenovirus (Ad5)(GL), Ad5/3luc1, Ad5lucRGD or Ad5pK7(GL). Mice immunized with Ad5(GL) featured reduced intravenous Ad5(GL) gene transfer to most organs, including the liver, lung and spleen. Ad5(GL) gene transfer was affected much less by exposure to capsid-modified viruses. Anti-Ad5(GL) NAb blocked intravenous Ad5(GL) gene transfer to orthotopic lung cancer xenografts, whereas capsid-modified viruses were not affected. When gene transfer to fresh cancer and normal lung explants was analyzed, we found that capsid-modified viruses allowed effective gene delivery to tumors in the presence of anti-Ad5(GL) NAb, whereas Ad5(GL) was blocked. In contrast, crossblocking by NAbs induced by different viruses affected gene delivery to normal human lung explants, suggesting the importance of non-fiber-knob-mediated infection mechanisms. We conclude that changing the adenovirus fiber knob is sufficient to allow a relative degree of escape from preexisting NAb. If confirmed in trials, this approach might improve the efficacy of re-administration of adenoviral gene therapy to humans.

Utility of TK/GCV in the context of highly effective oncolysis mediated by a serotype 3 receptor targeted oncolytic adenovirus

Arming oncolytic adenoviruses with therapeutic transgenes and enhancing transduction of tumor cells are useful strategies for eradication of advanced tumor masses. Herpes simplex virus thymidine kinase (TK) together with ganciclovir (GCV) has been promising when coupled with viruses featuring low oncolytic potential, but their utility is unknown in the context of highly effective infectivity-enhanced viruses. We constructed Ad5/3-Delta24-TK-GFP, a serotype 3 receptor-targeted, Rb/p16 pathway-selective oncolytic adenovirus, where a fusion gene encoding TK and green fluorescent protein (GFP) was inserted into 6.7K/gp19K-deleted E3 region. Ad5/3-Delta24-TK-GFP killed ovarian cancer cells effectively, which correlated with GFP expression. Delivery of GCV immediately after infection abrogated viral replication, which might have utility as a safety switch. Due to the bystander effect, killing of some cell lines in vitro was enhanced by GCV regardless of timing. In murine models of metastatic ovarian cancer, Ad5/3-Delta24-TK-GFP improved antitumor efficacy over the respective replication-deficient virus with GCV. However, GCV did not further enhance efficacy of Ad5/3-Delta24-TK-GFP in vivo. Simultaneous detection of tumor load and virus replication with bioluminescence and fluorescence imaging provided insight into the in vivo kinetics of oncolysis. In summary, TK/GCV may not add antitumor activity in the context of highly potent oncolysis.

The FinXX trial: Safety results in 600 patients (pts) randomized to either docetaxel (T) followed by cyclophosphamide (C) + epirubicin (E) + 5-FU (F) (CEF) or T + capecitabine (X) followed by CEX as adjuvant therapy for early breast cancer (BC)

11035

Background: Adding X to T extends survival in pts with metastatic BC. The primary objective of the FinXX trial is to compare recurrence-free survival with XT→CEX vs T→CEF as adjuvant therapy in pts with early stage BC. Secondary objectives were comparison of safety and overall survival. Methods: Between Jan 2004 and May 2005, 600 of a planned 1,500 pts were randomized to receive T x 3 → CEF x 3 (T 80 mg/m2 d1 → C 600 mg/m2 d1, E 75 mg/m2 d1, F 600 mg/m2 d1) or TX x 3 → CEX x 3 (T 60 mg/m2 d1 + X 900 mg/m2 bid d1–15 → C 600 mg/m2 d1, E 75 mg/m2 d1, X 900 mg/m2 bid d1–15) q3 wks. Results: Grade 3/4 toxicities (CTCAE, v3) in >5% of pts are shown below. 62 pts required G-CSF. Nos. of cycles with G-CSF were: T 34; XT 15; CEF 17; CEX 15. Adverse events (AEs) led to interruption of T in 7 pts (2%) and XT in 50 pts (16%). Median dose intensities at cycle 3 were T: 95%; XT: 84/97%; CEF: 98/97/98%; CEX: 98/98/84%. T dose reductions of =20% in cycle 3 were needed in 18% and 8% of pts receiving T and XT, respectively. 4 pts died during treatment: pulmonary embolism (n=1) with T and suicide, sudden death and colitis/sepsis (each n=1) with XT. Conclusions: XT→CEX is generally well tolerated. Treatment interruptions were more common with XT→CEX, but were effective in reducing development of grade 3/4 AEs. Neutropenic infections were less frequent with XT vs T and infrequent with XT, CEF and CEX. Rates of grade 3/4 diarrhea and HFS were acceptable with XT and minimal with CEX. Accrual is nearly complete; efficacy data are expected in 2009. [Table: see text]

[Table: see text]

Luciferase imaging for evaluation of oncolytic adenovirus replication in vivo

Oncolytic viruses kill cancer cells by tumor-selective replication. Clinical data have established the safety of the approach but also the need of improvements in potency. Efficacy of oncolysis is linked to effective infection of target cells and subsequent productive replication. Other variables include intratumoral barriers, access to target cells, uptake by non-target organs and immune response. Each of these aspects relates to the location and degree of virus replication. Unfortunately, detection of in vivo replication has been difficult, labor intensive and costly and therefore not much studied. We hypothesized that by coinfection of a luciferase expressing E1-deleted virus with an oncolytic virus, both viruses would replicate when present in the same cell. Photon emission due to conversion of D-Luciferin is sensitive and penetrates tissues well. Importantly, killing of animals is not required and each animal can be imaged repeatedly. Two different murine xenograft models were used and intratumoral coinjections of luciferase encoding virus were performed with eight different oncolytic adenoviruses. In both models, we found significant correlation between photon emission and infectious virus production. This suggests that the system can be used for non-invasive quantitation of the amplitude, persistence and dynamics of oncolytic virus replication in vivo, which could be helpful for the development of more effective and safe agents.

A three-dimensional assay for measurement of viral-induced oncolysis

Oncolytic viruses represent a novel cancer treatment strategy. Despite their promising preclinical data, however, corresponding clinical trials have disappointed. To aid preclinical analyses, we hypothesized that three-dimensional tumor cell clusters or spheroids might provide an assay system superior to conventional monolayer cell cultures. Spheroids show viral infection, replication and oncolytic patterns distinct from conventional monolayer assays. Therefore, viral tumor penetration and oncolysis measurements may be improved with such three-dimensional models. Also, preclinical analyses of oncolytic viruses frequently measure mitochondrial activity, but more accurate measures of oncolysis might involve quantitation of intracellular protein release. Therefore, we measured luciferase released from luciferase-expressing spheroids and found unique patterns that maintained consistency with various viruses and doses. The relative variations between viruses and doses may represent temporal differences in oncolysis dynamics. Analysis of five recombinant replicative adenoviruses with promise for clinical application showed that Ad5/3-Delta24 produced the most luciferase release 1 week after infection and achieved the earliest and highest peak luciferase release level. Ad5/3-Delta24 also effected the earliest subtotal spheroid cell death. These findings closely parallel monolayer oncolysis assays with these agents. Therefore, the luciferase-expressing tumor spheroid assay represents a promising three-dimensional model for preclinical analysis of replicative oncolytic agents.