A phase I trial of CV706, a replication-competent, PSA selective oncolytic adenovirus, for the treatment of locally recurrent prostate cancer following radiation therapy

CV706 is a prostate-specific antigen (PSA)-selective, replication-competent adenovirus that has been shown to selectively kill human prostate cancer xenografts in preclinical models. To study the safety and activity of intraprostatic delivery of CV706, a Phase I dose-ranging study for the treatment of patients with locally recurrent prostate cancer after radiation therapy was conducted. Twenty patients in five groups were treated with between 1 x 10(11) and 1 x 10(13) viral particles delivered by a real-time, transrectal ultrasound-guided transperineal technique using a three-dimensional plan. The primary end point was the determination of treatment-related toxicity. Secondary objectives included evaluation of the antitumor activity of CV706 and monitoring for other correlates of antineoplastic action. In this study, CV706 was found to be safe and was not associated with irreversible grade 3 or any grade 4 toxicity. No grade >1 alterations in liver function tests associated with CV706 administration were observed. Posttreatment prostatic biopsies and detection of a delayed "peak" of circulating copies of virus provided evidence of intraprostatic replication of CV706. The study defined the timing of CV706 shedding into blood and urine as well as the appearance of circulating Ad5 neutralizing antibodies. Finally, this study documents the serum PSA response of treated patients and reveals a dose response showing that all five patients who achieved a > or =50% reduction in PSA were treated with the highest two doses of CV706. This study represents the first clinical translation of a prostate-specific, replication-restricted adenovirus for the treatment of prostate cancer. Taken together, this study documents that intraprostatic delivery of CV706 can be safely administered to patients, even at high doses, and the data also suggest that CV706 possesses enough clinical activity, as reflected by changes in serum PSA, to warrant additional clinical and laboratory investigation.

Phase I trial of the matrix metalloproteinase inhibitor BAY12-9566 in patients with advanced solid tumors

PURPOSE

Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes that are believed to be involved in primary and metastatic tumor growth by degrading the basement membrane and changing the extracellular matrix to facilitate invasion of malignant cells and angiogenesis. Overexpression of MMPs has been documented in various solid tumors. BAY12-9566 is a selective inhibitor of MMPs, in particular MMP-2, -3. and -9. The purpose of this trial was to define the maximum tolerated dose (MTD), dose-limiting toxicities (DLT), safety profile, pharmacokinetics and pharmacodynamics of orally administered BAY12-9566 in patients with incurable solid tumors.

METHODS

The starting dose of BAY12-9566 for this single institution, outpatient phase I study was 100 mg/day orally. Patients were allowed to receive drug for up to 12 months. A total of 27 patients with various solid malignancies including colorectal, breast, lung, cervical and ovarian cancers were enrolled at doses from 100 to 1,600 mg/day. Patients were evaluated weekly while on treatment. Relevant radiologic examination was performed every 8 weeks to document and follow sites of measurable or evaluable disease.

RESULTS

Toxicities from BAY12-9566 included liver injury test abnormalities, anemia, shoulder and back pain. thrombocytopenia, mild nausea and fatigue, diarrhea, rash and deep vein thrombosis. No toxicity greater than grade III was observed. As doses were increased from 100 to 400 to 1,600 mg/day, even in divided doses, less than proportional increases in AUC were observed. At the highest dose level of 1600 mg/day, the day 29 AUC (3778.00 mg x h/l) remained similar to the day 29 AUC (3312.60 mg x h/l) at the dose level of 1200 mg/day. No responses were seen, but 14 patients remained on study with stable disease for 4 to 26 months.

CONCLUSIONS

BAY12-9566 was well tolerated at doses as high as 800 mg orally twice daily. Although mild alterations in liver injury tests, platelet count and hematocrit were noted, these were not dose-limiting. The drug was well absorbed. However, the absence of proportional increases in AUC with doses greater than 800 mg and the achievement of Css in the range associated with biologic activity in preclinical models led to the selection of 800 mg twice daily for further evaluation in phase III trials.

A Phase I clinical and pharmacological evaluation of sodium phenylbutyrate on an 120-h infusion schedule

PURPOSE

Sodium phenylbutyrate (PB) demonstrates potent differentiating capacity in multiple hematopoietic and solid tumor cell lines. We conducted a Phase I and pharmacokinetic study of PB by continuous infusion to characterize the maximum tolerated dose, toxicities, pharmacokinetics, and antitumor effects in patients with refractory solid tumors.

PATIENTS AND METHODS

Patients were treated with a 120-h PB infusion every 21 days. The dose was escalated from 150 to 515 mg/kg/day. Pharmacokinetics were performed during and after the first infusion period using a validated high-performance liquid chromatographic assay and single compartmental pharmacokinetic model for PB and its principal metabolite, phenylacetate.

RESULTS

A total of 24 patients were enrolled on study, with hormone refractory prostate cancer being the predominant tumor type. All patients were evaluable for toxicity and response. A total of 89 cycles were administered. The dose-limiting toxicity (DLT) was neuro-cortical, exemplified by excessive somnolence and confusion and accompanied by clinically significant hypokalemia, hyponatremia, and hyperuricemia. One patient at 515 mg/kg/day and another at 345 mg/kg/day experienced this DLT. Toxicity resolved < or =12 h of discontinuing the infusion. Other toxicities were mild, including fatigue and nausea. The maximum tolerated dose was 410 mg/kg/day for 5 days. Pharmacokinetics demonstrated that plasma clearance of PB increased in a continuous fashion beginning 24 h into the infusion. In individuals whose V(max) for drug elimination was less than their drug-dosing rate, the active metabolite phenylacetate accumulated progressively. Plasma PB concentrations (at 410 mg/kg/day) remained above the targeted therapeutic threshold of 500 micromol/liter required for in vitro activity.

CONCLUSION

The DLT in this Phase I study for infusional PB given for 5 days every 21 days is neuro-cortical in nature. The recommended Phase II dose is 410 mg/kg/day for 120 h.

A phase I dose escalation and bioavailability study of oral sodium phenylbutyrate in patients with refractory solid tumor malignancies

PURPOSE

Phenylbutyrate (PB) is an aromatic fatty acid with multiple mechanisms of action including histone deacetylase inhibition. Preclinically, PB demonstrates both cytotoxic and differentiating effects at a concentration of 0.5 mM. We conducted a Phase I trial of p.o. PB patients with refractory solid tumor malignancies to evaluate toxicity, pharmacokinetic parameters, and feasibility of p.o. administration.

EXPERIMENTAL DESIGN

Twenty-eight patients with refractory solid tumor malignancies were enrolled on this dose-escalation to maximally tolerated dose trial. Five dose levels of PB were studied: 9 g/day (n = 4), 18 g/day (n = 4), 27 g/day (n = 4), 36 g/day (n = 12), and 45 g/day (n = 4). Pharmacokinetic studies were performed and included an p.o. bioavailability determination. Compliance data were also collected.

RESULTS

The recommended Phase II dose is 27 g/day. Overall the drug was well tolerated with the most common toxicities being grade 1-2 dyspepsia and fatigue. Nonoverlapping dose-limiting toxicities of nausea/vomiting and hypocalcemia were seen at 36 g/day. The p.o. bioavailability of PB was 78% for all dose levels, and the biologically active concentration of 0.5 mM was achieved at all dose levels. Compliance was excellent with 93.5% of all possible doses taken. No partial remission or complete remission was seen, but 7 patients had stable disease for more than 6 months while on the drug.

CONCLUSIONS

PB (p.o.) is well tolerated and achieves the concentration in vivo that has been shown to have biological activity in vitro. PB may have a role as a cytostatic agent and should be additionally explored in combination with cytotoxics and other novel drugs.

Combination of phenylbutyrate and 13-cis retinoic acid inhibits prostate tumor growth and angiogenesis

Differentiation-inducing agents, such as retinoids and short-chain fatty acids, have an inhibitory effect on tumor cell proliferation and tumor growth in preclinical studies. Clinical trials involving these compounds as single agents have been suboptimal in terms of clinical benefit. Our study evaluated the combination of phenylbutyrate (PB) and 13-cis retinoic acid (CRA) as a differentiation and antiangiogenesis strategy for prostate cancer. On the basis of previous evidence, common signal transduction pathways and possible modulation of retinoid receptors and retinoid response elements by PB could be responsible for such activities. We assessed the effect of the combination of PB and CRA on human and rodent prostate carcinoma cell lines. The combination of PB and CRA inhibited cell proliferation and increased apoptosis in vitro in an additive fashion as compared with single agents (P < 0.014). Prostate tumor cells treated with both PB and CRA revealed an increased expression of a subtype of retinoic acid receptor (retinoic acid receptor-beta), suggesting a molecular mechanism for the biological additive effect. The combination of PB and CRA also inhibited prostate tumor growth in vivo (up to 82-92%) as compared with single agents (P < 0.025). Histological examination of tumor xenografts revealed decreased in vivo tumor cell proliferation, an increased apoptosis rate, and a reduced microvessel density in the animals treated with combined drugs, suggesting an antiangiogenesis effect of this combination. Thus, endothelial cell treatment with both PB and CRA resulted in reduced in vitro cell proliferation. In vivo testing using the Matrigel angiogenesis assay showed an additive inhibitory effect in the animals treated with a combination of PB + CRA (P < 0.004 versus single agents). In summary, this study showed an additive inhibitory effect of combination of differentiation agents PB and CRA on prostate tumor growth through a direct effect on both tumor and endothelial cells.

Modifying histones to tame cancer: clinical development of sodium phenylbutyrate and other histone deacetylase inhibitors

Compounds that inhibit histone deacetylase may enable the re-expression of silenced regulatory genes in neoplastic cells, reversing the malignant phenotype. Although several molecules that inhibit histone deacetylase are undergoing preclinical development, butyric acid derivatives have undergone clinical investigation for several years, initially for non-malignant indications and more recently for the treatment of cancer. Of the butyric acid derivatives, sodium phenylbutyrate has undergone the most extensive systematic investigation. Administration of phenylbutyrate by iv. and oral routes is well-tolerated clinically at concentrations which effect acetylation of histones in vitro. Higher doses lead to reversible CNS depression. The studies presented to date have been Phase I studies and do not enable assessment of efficacy. However, current development of phenylbutyrate is proceeding in combination with other agents based on rational biologically-based in vitro studies. The parallel development of combination therapy including phenylbutyrate and early clinical development of other, more potent histone deacetylase inhibitors will hopefully lead to feasible, clinically tolerable strategies for altering the malignant phenotype of cancer cells.

Cancer cells engineered to secrete granulocyte-macrophage colony-stimulating factor using ex vivo gene transfer as vaccines for the treatment of genitourinary malignancies

When irradiated and administered intradermally as vaccines, cancer cells engineered to secrete high levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) by gene transfer elicit potent anticancer immune responses in a variety of animal tumor models. Upon vaccination, antigens present in the cancer cells are phagocytosed and processed by skin dendritic cells. These dendritic cells then prime anticancer immune responses by presenting antigenic peptides to T cells. The immune responses generated are capable of eradicating small but lethal cancer cell inocula with minimal toxicity in preclinical animal tumor studies. To develop this vaccination strategy for the treatment of human genitourinary cancers, we have conducted phase I clinical trials using human genitourinary cancer cells as sources of cancer cell antigens. In the first human clinical trial of genetically engineered cancer cell vaccines, a phase I clinical trial of kidney cancer cell vaccines (n = 18), kidney cancer cells were removed at surgery, propagated briefly in vitro, and then genetically modified to secrete high levels of GM-CSF via ex vivo transduction with the retrovirus MFG-GM-CSF. After irradiation, the kidney cancer cells were administered as vaccines to 18 patients with advanced kidney cancers. Vaccine treatment, which caused few side effects, nonetheless appeared to trigger anticancer immune responses manifest as conversion of delayed-type hypersensitivity (DTH) skin responses against irradiated autologous cancer cells after vaccination. Biopsies of vaccine sites yielded findings reminiscent of biopsies from preclinical animal model studies, with evidence of vaccine cell recruitment of dendritic cells, T cells, and eosinophils. One patient with measurable kidney cancer metastases treated at the highest vaccine dose level experienced a partial treatment response. The bioactivity of GM-CSF-secreting autologous cancer cell vaccines was confirmed in a phase I clinical trial for prostate cancer (n = 8). Vaccine cells were prepared from surgically harvested prostate tumors by ex vivo transduction with MFG-GM-CSF in a manner similar to that used for the kidney cancer trial. Vaccine treatment was well tolerated and associated with induction of anticancer immunity as assessed using DTH skin testing. In addition, new antiprostate cancer cell antibodies were detected in serum samples from treated men as a consequence of vaccination. These first clinical trials of GM-CSF-secreting cancer cell vaccines for the treatment of genitourinary cancers have demonstrated both safety and bioactivity, in that very few side effects have been seen and anticancer immune responses have been detected. Future clinical studies will be required to assess vaccine treatment efficacy, refine vaccination dose and schedule, define the appropriate clinical context for the use of such vaccines, and ascertain optimal combinations involving vaccines and other local or systemic anticancer treatments.

Complete androgen blockade for prostate cancer: what went wrong?

PURPOSE

We summarized and critically assessed all available data from phase III clinical trials on complete androgen blockade versus surgical or medical castration alone.

MATERIALS AND METHODS

Published results in journals and abstracts of phase III trials, and published meta-analyses were reviewed. We also reviewed quality of life and toxicity issues associated with the addition of antiandrogens to medical or surgical castration. Finally, we discuss the original rationale for complete androgen blockade in the context of current knowledge.

RESULTS

A total of 27 clinical trials using various combinations of androgen deprivation were identified, of which 3 showed a statistically significant benefit for the complete androgen blockade arm. There were 5 publications of meta-analyses that each used different selection criteria for the inclusion of studies in the final analysis. Toxicity and quality of life have not been widely investigated in prospective fashion but the available data suggest a higher toxicity rate and decreased quality of life with complete androgen blockade.

CONCLUSIONS

The extensive body of data does not support routine use of antiandrogens in combination with medical or surgical castration as first line hormonal therapy in patients with metastatic prostate cancer.

Identification and characterization of circulating prostate carcinoma cells

BACKGROUND

Analysis of prostate carcinoma cells isolated from the peripheral blood suggested a classification based on three categories.

METHODS

Centrifugation density gradients and magnetic cell sorting were used to isolate circulating prostate carcinoma cells from peripheral blood. Immunocytochemistry staining and fluorescent in situ hybridization allowed characterization of isolated cancer cells.

RESULTS

Terminal cells can be divided into 3 classes: 1) large, buoyant, fragile cells with a large nucleus that were captured in a 1.068 g/mL gradient; 2) enucleate cells (4, 6-diamidino-2-phenylindole [DAPI] negative) that were positive for cytokeratin and PSMA antibodies; and 3) cellular debris exhibiting cytokeratin and PSMA positive staining as well as nuclear debris identified by DAPI staining, which included cytoplasmic debris. Growing cells also exhibited three morphologic characteristics: those possessing stem cell-like morphology and characteristics such as small size, high density, developed cytokeratin systems, PSMA expression, and aneuploidy; those in M phase; and cell clusters. The majority of isolated cells exhibited intermediate characteristics and thus comprised the third group of circulating cancer cells.

CONCLUSIONS

Although the significance of the cluster remains undetermined, observation suggests that the cluster has the ability to circulate as a microtumor and subsequently arrest in the small veins and capillaries. It is hypothesized that the clusters could escape certain facets of immune surveillance and possibly gain a selective growth advantage over single cells in a distant site. Further hypothesis proposes that arrested cells recruit growth-promoting nutrients, which would result in the invasion of local blood vessels and vascularization.

Induction of immunity to prostate cancer antigens: results of a clinical trial of vaccination with irradiated autologous prostate tumor cells engineered to secrete granulocyte-macrophage colony-stimulating factor using ex vivo gene transfer

Vaccination with irradiated granulocyte-macrophage colony-stimulating factor (GM-CSF)-secreting gene-transduced cancer vaccines induces tumoricidal immune responses. In a Phase I human gene therapy trial, eight immunocompetent prostate cancer (PCA) patients were treated with autologous, GM-CSF-secreting, irradiated tumor vaccines prepared from ex vivo retroviral transduction of surgically harvested cells. Expansion of primary cultures of autologous vaccine cells was successful to meet trial specifications in 8 of 11 cases (73%); the yields of the primary culture cell limited the number of courses of vaccination. Side effects were pruritus, erythema, and swelling at vaccination sites. Vaccine site biopsies manifested infiltrates of dendritic cells and macrophages among prostate tumor vaccine cells. Vaccination activated new T-cell and B-cell immune responses against PCA antigens. T-cell responses, evaluated by assessing delayed-type hypersensitivity (DTH) reactions against untransduced autologous tumor cells, were evident in two of eight patients before vaccination and in seven of eight patients after treatment. Reactive DTH site biopsies manifested infiltrates of effector cells consisting of CD45RO+ T-cells, and degranulating eosinophils consistent with activation of both Th1 and Th2 T-cell responses. A distinctive eosinophilic vasculitis was evident near autologous tumor cells at vaccine sites, and at DTH sites. B-cell responses were also induced. Sera from three of eight vaccinated men contained new antibodies recognizing polypeptides of 26, 31, and 150 kDa in protein extracts from prostate cells. The 150-kDa polypeptide was expressed by LNCaP and PC-3 PCA cells, as well as by normal prostate epithelial cells, but not by prostate stromal cells. No antibodies against prostate-specific antigen were detected. These data suggest that both T-cell and B-cell immune responses to human PCA can be generated by treatment with irradiated, GM-CSF gene-transduced PCA vaccines.

Rapid disease progression after the administration of bicalutamide in patients with metastatic prostate cancer

We report 5 patients with advanced metastatic prostate cancer who took bicalutamide 50 mg/day for "second-line" hormonal manipulation and demonstrated a rapid rise in prostate-specific antigen (PSA) shortly after the initiation of bicalutamide. After discontinuation of the drug, PSA levels declined in 4 patients and stabilized in the fifth. In 2 of the patients, the PSA rise was associated with an increase in pain level, which subsided after the treatment was stopped. The timing of the rapid changes in PSA and pain levels suggests a direct effect of bicalutamide. The most probable explanation for this observation is a very early agonist activation of androgen receptor by bicalutamide, similar to the underlying mechanism of the "antiandrogen withdrawal syndrome."

Prostate-specific antigen and other markers of therapeutic response

Several new agents and combinations demonstrate significant activity in the treatment of patients with hormone refractory prostate cancer. Prostate-specific antigen (PSA) is being used increasingly as the key marker of a therapeutic response in trials of new agents. This article reviews data that support this marker as a surrogate endpoint, and it discusses the issues around the appropriateness of PSA as an intermediate marker with evolving noncytotoxic agents. Other biomarkers of prostate cancer progression are not uniformly elevated in men with advanced disease; to date, they are of limited clinical use. This article also discusses the rationale and results of novel and alternative biomarkers of prostate cancer progression.

Nuclear morphometry adds significant prognostic information to stage and grade for renal cell carcinoma

OBJECTIVES

Identification of patients with a high probability of recurrence after nephrectomy for renal cell carcinoma (RCC) is required for adjuvant studies of new therapies. Nuclear morphometry predicts prognosis for prostate, bladder, and Wilms' tumors and in RCC according to previous small pilot studies.

METHODS

To validate this finding, we studied an additional 101 patients who underwent nephrectomy for Stage pT1 to pT3 RCC at our institution from 1977 to 1993 for whom data regarding recurrence or disease-free survival of greater than 60 months were available. Patient records and pathology specimens were reviewed. Of the 101 patients, 66 (65%) did not experience recurrence with greater than 60 months of follow-up, and 35 (35%) had RCC recurrence with a median time to recurrence of 17 months. Nuclear shape descriptors were tested as predictors of disease recurrence after accounting for stage and grade in proportional hazards regression models.

RESULTS

Range of ellipticity (hazards ratio 3.39, P = 0.014) was confirmed to be a significant predictor of recurrence. A prognostic model using stage, grade, and range of ellipticity identified three distinct groups: low, moderate, and high recurrence risk groups, with recurrence rates of 4%, 37%, and 63%, respectively, at 5 years of follow-up. Morphometry significantly (P = 0.018) improved prognostication on the basis of stage and grade alone in this multivariate model.

CONCLUSIONS

Nuclear morphometry is valid and accurate in predicting relapse in early-stage RCC. The model can select patients with RCC for adjuvant therapies.

Impaired expression and function of signal-transducing zeta chains in peripheral T cells and natural killer cells in patients with prostate cancer

Detection of functional, circulating T cells and NK cells may serve as a clinical test for the selection of individuals who can benefit from immunotherapy. Incidence of the T-cell receptor zeta (TCRdelta) chain within these populations appears to correlate with adequate effector cell function. In patients with advanced malignancy, the absence or reduced expression of delta chain has been documented. Flow cytometric analysis in the present study revealed a significant reduction in delta chain expression in peripheral blood lymphocytes (PBL) of 14 of 22 prostate cancer patients (P < 0.000001) as compared to normal donors, apparent in both T cells (CD3+, CD4+, CD8+), and NK (CD16+) cells. Compared to normal donor PBL, patient PBL cultured in the presence of CD3 and CD28, also demonstrated reduced expression of CD69 and/or CD25, and in some cases, failed to activate at all. Furthermore, evidence of cell proliferation in activation-stimulated patient PBL was muted: average PCNA positivity equaled 14%, a marked difference from what was observed in normal donors (P < 0.0002). In 8 of 16 samples of PBL, where delta expression was originally low, delta levels returned to the normal range after 48 hour culture in serum-free medium, suggesting that the loss of delta is reversible and may be caused by a tumor-derived substance. These data support the premise that monitoring the expression of delta in a cancer patient may provide a unique insight into the immune status and functionality of the individual, with the potential to redirect or augment therapies and ultimately alter prognosis.

Allopurinol-induced pyrimidinuria in cancer patients

Allopurinol induced pyrimidinuria is a sensitive and specific test that identifies the increased de novo pyrimidine mononucleotide biosynthesis accompanying ornithine trans carbamylase deficiency. We hypothesize that the increased de novo DNA synthesis characteristic of malignant tumors can be detected using this method. Eleven cancer patients and a 30 subject control group were studied. The allopurinol test protocol consists of five urine collection periods--a baseline collection after which time a 300 mg dose of allopurinol is taken, followed by collection of four 6 hour fractional urine collections. Orotate, orotidine and creatinine were measured on the samples. Eight of 11 patients had significantly elevated urine levels of either orotate or orotidine either prior to challenge with allopurinol or during one of the time periods. The allopurinol test for this unstratified group has a sensitivity of 0.73 and a specificity of 1.0. This observational and preliminary report suggest that further study of the potential significance and usefulness of the allopurinol test in patients at risk for or with malignancy is warranted.

Cytotoxic effects of sodium phenylbutyrate on human neuroblastoma cell lines

Sodium phenylbutyrate (NaPB) is used in urea cycle disorders. We screened 6 neuroblastoma cell lines for in vitro potency of NaPB as an antiproliferative agent, evaluated multiple dosing schedules, and assessed its activity in combination with clinically active agents for neuroblastoma. We determined that NaPB achieves a 30-80% growth inhibition at 5 mM. Repeated dosing and prolonged drug exposure enhanced the cytotoxic effect. NaPB had additive cytotoxic effects when administered with vincristine; however, NaPB did not affect the activity of etoposide, adriamycin, 4-hydroxycyclophosphamide or cisplatinum. These results suggest that NaPB is an active agent against neuroblastoma and could be combined with vincristine in novel chemotherapy regimens.

Bioactivity of autologous irradiated renal cell carcinoma vaccines generated by ex vivo granulocyte-macrophage colony-stimulating factor gene transfer

Granulocyte-macrophage colony-stimulating factor (GM-CSF) gene-transduced, irradiated tumor vaccines induce potent, T-cell-mediated antitumor immune responses in preclinical models. We report the initial results of a Phase I trial evaluating this strategy for safety and the induction of immune responses in patients with metastatic renal cell carcinoma (RCC). Patients were treated in a randomized, double-blind dose-escalation study with equivalent doses of autologous, irradiated RCC vaccine cells with or without ex vivo human GM-CSF gene transfer. The replication-defective retroviral vector MFG was used for GM-CSF gene transfer. No dose-limiting toxicities were encountered in 16 fully evaluable patients. GM-CSF gene-transduced vaccines were equivalent in toxicity to nontransduced vaccines up to the feasible limits of autologous tumor vaccine yield. No evidence of autoimmune disease was observed. Biopsies of intradermal sites of injection with GM-CSF gene-transduced vaccines contained distinctive macrophage, dendritic cell, eosinophil, neutrophil, and T-cell infiltrates similar to those observed in preclinical models of efficacy. Histological analysis of delayed-type hypersensitivity responses in patients vaccinated with GM-CSF-transduced vaccines demonstrated an intense eosinophil infiltrate that was not observed in patients who received nontransduced vaccines. An objective partial response was observed in a patient treated with GM-CSF gene-transduced vaccine who displayed the largest delayed-type hypersensitivity conversion. No replication-competent retrovirus was detected in vaccinated patients. This Phase I study demonstrated the feasibility, safety, and bioactivity of an autologous GM-CSF gene-transduced tumor vaccine for RCC patients.

Prostate cancer treatment strategies based on tumor-specific biological principles: future directions

Prostate cancer represents a heterogeneous disease entity with varying degrees of behavior, aggressiveness, patterns of metastasis, and response to therapy. Progressive metastatic prostate cancer is associated with a formidable array of morbidity that ultimately contributes to death of the patient. Thus far, there has been no convincing evidence to support routine use of non-hormonal chemotherapeutic agents or combinations over symptomatic treatment only. Furthermore, no single compound or combination has shown a dramatic improvement in conventional quality of life parameters over symptomatic treatment only. Androgen ablation remains the primary systemic therapeutic modality for this disease, yet the intense delineation of mechanisms involved in tumor cell metastasis has lead to new therapeutic strategies, ranging from cytotoxic to cytostatic, including immunomodulators. Among those strategies currently being studied are granulocyte-macrophage colony-stimulating factor-transduced prostate cancer vaccines, differentiation therapy, gene therapy, inducers of apoptosis, antimetastatic agents, angiogenesis inhibitors, radiation therapy (local and systemic), and systemic approaches targeted at prostate cancer morbidity. The difficult issue is which agents should be developed and how should we best assess the response using standard and newly identified endpoints. Certainly, the future of advanced prostate cancer therapy will undergo dramatic changes as a result of the continued interaction between the laboratory and the clinic.

Early evaluation of abdominal/hepatic irradiation and 5-fluorouracil/leucovorin infusion after pancreaticoduodenectomy

PURPOSE

To describe the toxicities of a combined modality adjuvant regimen for patients with resectable periampullary adenocarcinoma.

METHODS AND MATERIALS

Fourteen patients with surgically resected periampullary adenocarcinoma were treated with adjuvant therapy consisting of prophylactic hepatic irradiation and pancreatic bed irradiation and concurrent infusional 5-fluorouracil and leucovorin (5-FU/LV). Starting within 60 days of surgery, patients received radiation treatments of 1.8 Gy per fraction to the liver and pancreatic bed (13 fractions), followed by 1.8 Gy per fraction to the pancreatic region (15 fractions). All radiation treatments were given with infusional 5-FU (200 mg/m2/day) and leucovorin (5 mg/m2/day) for 5 out of every 7 days during the 38-day treatment sequence. After a 1-month break, patients were scheduled to receive four cycles of infusional 5-FU/LV (2 weeks on/2 weeks off).

RESULTS

All 14 patients completed the initial combination treatment. Toxicities were tolerable; three patients had Grade 3/4 toxicities that were primarily gastrointestinal in nature. Six patients required hospitalization during therapy for treatment-related toxicities. Two patients required radiation treatment breaks of less than 1 week, and two others had radiation held for 2-4 weeks. Three patients required chemotherapy dose reductions secondary to toxicities. Toxicities in the subsequent chemotherapy-alone cycles were few and primarily manifested by Grade 2 rises in liver injury tests. Higher toxicity grades were associated with tumor progression. Twelve patients have developed recurrent disease with an equal number of recurrences occurring in the pancreatic bed as in the liver over the 12-month median follow-up. Median survival for this cohort is 417 days, not significantly different from previously reported adjuvant trials in this patient population.

CONCLUSION

These data indicate that adjuvant therapy with concomitant large-field radiation and infusional chemotherapy is feasible and associated with mangeable toxicities in patients undergoing pancreaticoduodenectomy for periampullary adenocarcinoma. Improvement in survival over other adjuvant regimens has not thus far been observed. Modification of this strategy may be required.