Antitumor Effects In Patients Research Articles

Combining a Peptide Vaccine With High-Dose Interleukin-2

High-dose interleukin-2 (IL-2) is a US Food and Drug Administration–approved treatment for metastatic melanoma. It was originally developed at the National Cancer Institute (NCI) Surgery Branch and represents one of the few examples in which antitumor effects seen in mice correctly predicted antitumor effects in patients. The initial clinical report, which used recombinant IL-2 plus lymphokine-activated killer cells (now known to be mostly natural killer cells), reported a 44% response rate. 1 This caught everybody’s attention. Subsequently, over the next 9 years, as more patients were treated with IL-2 alone, the NCI Surgery Branch reported progressively lower response rates from 31% 2 to 24% 3 and finally to 17%. 4 Consistent with this, a pooled analysis of seven NCI-sponsored trials, representing 270 patients, reported a response rate of 16% with IL-2. 5 It is this number, 16%, that is most commonly cited as the response rate for high-dose IL-2. However, the substage of metastatic melanoma is an important predictor of response to IL-2. Durable responses are more common in patients with either M1a disease (subcutaneous sites only) or M1b disease (lung metastases) and much less common in patients with M1c disease. 5,6 The importance of this will be discussed further in this editorial. Subsequent efforts by the NCI Surgery Branch to improve the

Biweekly Triple Combination Chemotherapy with Gemcitabine, Oxaliplatin, Levofolinic Acid and 5-Fluorouracil (GOLF) Is a Safe and Active Treatment for Patients with Inoperable Pancreatic Cancer

GOLF is a triple translational combination chemotherapy regimen with gemcitabine, oxaliplatin, and 5-fluorouracil (5-FU) (plus levofolinic acid), cytotoxic drugs currently used in the treatment of pancreatic carcinoma. Considering its promising anti-tumor effects in patients with gastroenteric malignancies, we carried out the present study to investigate its toxicity and anti-tumor activity in patients with advanced pancreatic carcinoma. Twenty-seven patients were enrolled in the study, 15 males and 12 females with an average age of 61 years and a performance status (ECOG) ≤3. Eight of them had already received first-line chemotherapy, 16 had liver involvement and 11 had inoperable locally (nodes, soft tissue infiltration, peritoneum etc) advanced disease. All patients received biweekly gemcitabine (1000 mg/m2 on day 1), oxaliplatin (85 mg/m2 on day 2); levofolinic acid (100 mg/m2) and 5-FU (400 mg/m2 as bolus, and 800 mg/m2 in 24-h infusion) on days 1 and 2. We report one fatal event occurring just after the first cycle due to lung embolism; grade II-III-diarrhea and mucosytis (44.4%); alopecia (37%); thrombocytopenia (18.5%); grade I-II asthenia, fatigue, non-neutropenic-fever (37%) and oxaliplatinrelated neurotoxicity (18.5%). We also registered fast pain control in most patients, an objective response and disease control rate of 33.3% and 63% (1 complete and 8 partial responses and 8 disease stabilizations) respectively, with clinical benefit in 60% of patients and median time to progression and overall survival of 5.5 and 8 months, respectively.In conclusion, the GOLF regimen appears to be a feasible treatment for patients with advanced pancreatic carcinoma that deserves to be evaluated in phase III trials.

A Phase II Trial of Bortezomib and Prednisone for Castration Resistant Metastatic Prostate Cancer

We defined the antitumor effects of bortezomib alone and in combination with prednisone in patients with progressive, castration resistant metastatic prostate cancer. A total of 30 men with progressive castration resistant disease were treated in 2 groups. Cohort 1 received 1.5 mg/m2 bortezomib intravenously twice weekly for 2 cycles (2 weeks on and 1 week off), followed by 1.6 mg/m2 weekly (4 weeks on and 2 weeks off). Prednisone (10 mg) was given orally throughout. Cohort 2 comprised patients with limited chemotherapy exposure who received a decreased dose of bortezomib (1.3 mg/m2) during the induction period with prednisone added only at disease progression. The primary end point was no evidence of disease progression at 12 weeks, defined as no increase in prostate specific antigen from baseline and no radiographic progression. Interleukin-6 was assessed to correlate with antitumor effects. One of 24 evaluable patients (4%) achieved the primary end point. In cohort 1, 18 patients were treated, 13 were evaluable for response and 4 discontinued treatment due to toxicities, including 3 before attaining the point of being evaluable. No patient achieved the primary end point. In cohort 2, 12 patients were treated and 11 were evaluable for response. Toxicity was slightly mitigated compared with that in cohort 1. One patient achieved the primary end point. Interleukin-6 did not correlate with posttreatment prostate specific antigen changes in either cohort. Although interleukin-6 and other pathways regulated by nuclear factor-kappa B may be legitimate targets, treatment with bortezomib alone and with prednisone does not appear to have significant antitumor effects in patients with castration resistant metastatic prostate cancer.

Therapy with Bortezomib plus Dexamethasone Induces Osteoblast Activation in Responsive Patients with Multiple Myeloma

Bortezomib is a novel proteasome inhibitor that has shown marked antitumor effects in patients with multiple myeloma (MM). We evaluated the feasibility and efficacy of bortezomib plus dexamethasone (BD) therapy and assessed bone metabolism in relapsed or refractory MM. Fourteen patients received 1.3 mg/m2 bortezomib on days 1, 4, 8, and 11 along with 20 mg/dose of dexamethasone on days 1, 2, 4, 5, 8, 9, 11, and 12 in a 21-day cycle. After 1 to 3 cycles of BD therapy, 9 patients (64%) achieved an objective response (5 very good partial responses and 4 partial responses). Notably, a rapid increase in the serum concentration of alkaline phosphatase (ALP) was observed in 6 of the treatment-responsive patients. Moreover, serum levels of bone-formation markers (bone-specific ALP and osteocalcin) significantly increased in 5 and 2 responsive patients, respectively. Radiographic examination showed improvement in bone lesions, suggesting that BD therapy induces osteoblast activation in responders. Adverse events included thrombocytopenia of grades 1 to 3, peripheral neuropathy of grades 1 to 2, and grade 3 ileus and were transient and manageable. Although severe lung injury has been reported among Japanese patients treated with bortezomib, no pulmonary complications were observed during BD therapy. Our results suggest that BD therapy is a safe and promising therapeutic approach for Japanese patients with MM.

Trail-Receptor Antibodies As A Potential Cancer Treatment

Increasing attention has been focused on the use of agonistic monoclonal antibodies against TNF-related apoptosis-inducing ligand (TRAIL) death receptors DR4 or DR5 as a potential cancer treatment. These antibodies have strong apoptosis-inducing activity against cancer cells and potent antitumor activity against tumor xenografts in preclinical models that are enhanced by combination chemotherapy treatment. There are several agonistic humanized or human monoclonal antibodies against DR4 and DR5 that have been tested in Phase I and II trials in patients with advanced cancer. These trials have demonstrated these antibodies to be well tolerated, and to produce prolonged stable disease, which is the best antitumor effect in patients with advanced cancer. Clinical studies in which TRAIL-receptor antibodies are being investigated in combination treatment regimens in patients with advanced cancer are ongoing. It is anticipated that the results from a broad spectrum of cancer therapy clinical trials will identify the activity and toxicity profiles of TRAIL death-receptor antibodies as a single agent, or in combination with chemotherapy agents or radiation therapy.

Intratumoral injection of dendritic cells in combination with local hyperthermia induces systemic antitumor effect in patients with advanced melanoma

Dendritic cells (DC) are potent antigen-presenting cells that can present tumor antigens chaperoned by heat shock proteins (HSPs), while local hyperthermia (LHT) can increase the expression of HSPs. In this study, we determine if intratumoral injection of immature DC after LHT (LHT+IT-DC) induces systemic antitumor immunity in patients with advanced melanoma, and investigate the potential immunological mechanisms involved in the treatments. Patients were randomly assigned to intratumoral administration of autologous immature DC triweekly, with (LHT+IT-DC, arm A, n = 9) or without (IT-DC, arm B, n = 9) LHT. Our results showed that there were no grade 3/4 toxicities. The time to progress (TTP) of arm A was 5 months, significantly longer than that in arm B (2 months, p < 0.05). However, the overall survival time had no statistical difference (13 months vs. 6 months, p > 0.05) between the 2 groups. Our ELISPOT assay showed a significantly increased melanoma-specific IFN-gamma production in arm A, suggesting that LHT+IT-DC was more effective in the induction of cytotoxic T lymphocytes (CTL) than IT-DC alone. Furthermore, we detected an increased HSPs expression 4 hr after the first LHT, an enhanced Th1/Th2 chemokines production 24 hr after the first LHT+IT-DC treatment, a promoted migration of DC to afferent lymph nodes, and a decreased infiltration of regulatory T cells (CD4(+)CD25(+)) and an increased infiltration of active CTL (CD8(+)CD28(+)) 48 hr after the third DC injection in arm A patients. Therefore, LHT+IT-DC can induce effective specific antitumor immunity and facilitate a Th1-polarized immune response in patients with advanced melanoma.

A Phase II Trial of Docetaxel Plus Capecitabine in Patients with Previously Treated Non-Small Cell Lung Cancer

A combination of docetaxel (T) and capecitabine (X) showed synergistic effects in preclinical studies and phase III randomized trials of metastatic breast cancer. We conducted this phase II study to examine its efficacy in previously treated non-small cell lung cancer (NSCLC) patients. Patient eligibility required advanced NSCLC with measurable lesion(s), at least one prior regimen failure and Eastern Cooperative Oncology Group (ECOG) performance status 0-2. Treatment consisted of T 36 mg/m(2) i.v. on days 1 and 8 plus X 1000 mg/m(2) p.o. b.i.d. on days 1-14 of a 21-day cycle (level I) or T 30 mg/m(2) i.v. on days 1 and 8 plus X 625 mg/m(2) p.o. b.i.d. on days 1-14 of a 21-day cycle (level II). A total of 35 patients (M/F=24/11) were enrolled; 29 had received one prior regimen and 19 had received platinum-based regimens. Significant non-hematologic toxicities were observed after the treatment given at level I, including one treatment-related death. Subsequently 29 patients were treated at level II. The treatment at level II was well tolerated with grade 3 or 4 neutropenia only in 10%, grade 3 asthenia in 21% and stomatitis in 14% of patients. Four (15%) of 27 evaluable patients had partial response (PR) at level II and eight (30%) had stable disease (SD). The TX regimen showed modest antitumor effects in patients with previously treated NSCLC. For further studies, we recommend T 30 mg/m(2) i.v. on days 1 and 8 plus X 625 mg/m(2) p.o. b.i.d. on days 1-14 of a 21-day cycle.

Sirolimus and everolimus: inhibitors of mammalian target of rapamycin in liver transplantation

Sirolimus (SRL) and everolimus are members of a relatively new class of immunosuppressants that impair cell cycle proliferation by inhibition of the mammalian target of rapamycin. These agents have been evaluated and licensed for use in kidney transplantation where they are used predominantly as maintenance immunosuppression because they lack the nephrotoxicity associated with calcineurin inhibitors. Neither SRL nor its newer analogue everolimus are currently licensed for use in liver transplantation, but both have been used with varying degrees of success and efficacy in this setting. Concern has been expressed about a potential association between de novo use of SRL and both a high incidence of hepatic artery thrombosis after liver transplantation and impaired wound healing, and thus, subsequent development has focused on the use of SRL in response to calcineurin inhibitor toxicity in patients with established liver transplants as well as using its potential antitumor effects in patients transplanted for malignancy. This article reviews the reported experience of mammalian target of rapamycin inhibitor therapy in liver transplantation.

Synthesis of Naringenin Amino Acid Esters as Potential CDK2 Inhibitors

The central role of cyclin-dependent kinases (CDKs) in cell cycle regulation makes them a promising target for studying inhibitory molecules that can modify the degree of cell proliferation. The discovery of specific inhibitors of CDKs such as polyhydroxylated flavones has opened the way to investigation and design of antimitotic compounds. Among the polyhydroxylated flavones, flavopiridol (1, Figure 1) has completed phase I clinical trial where it showed antitumor effect in patients with refractory neoplasms. This encouraging result, which is consistent with the ability of 1 to inhibit proliferation of cancer cells in vitro makes polyhydroxylated flavone an interesting target for further analogue synthesis. In continuation of our studies aimed toward the development of more potent and more selective anticancer agents, we designed flavone derivatives for further biological evaluation. The flavone naringenin is widely spread in nature and easily extracted from a lot of different plants. Their protective effect against lipid peroxidation of membranes, involved in several physiological and pathological disorders, as aging, inflammation, atherosclerosis, ischemia, toxicity of oxygen and chemical substances has been largely reported. Thus, interesting biological activity as well as structural similarity with flavopiridol makes naringenin one of the most interesting candidates for designing novel CDK2 inhibitors. However, derivatives of naringenin have not been studied extensively presumably due to the synthetic difficulties. Particularly, naringenin is awkward to make derivatives due to its low solubility in water as well as in organic solvents. In view of designing naringenin derivatives, the 7-O position of naringenin (2, Figure 1) is particularly attractive because it is well known that electrophiles react with hydroxyl group preferentially at the 7-position. Also, comparison of the biological activity of 7-O-substitued naringenin with that of flavopiridol would provide interesting insights into designing novel flavonoid CDK2 inhibitors due to their subtle distinction in three dimensional structures. On the other hand, as a limiting factor of the use of flavonoids is their low water solubility, another aim of this study was to increase the solubility and dissolution rate of naringenin by conjugate formation with polar substituents. Thus, we set out to prepare various naringenin-amino acid conjugates (2, Figure 1) because amino acids substituted at the 7-O position would serve as an excellent model for our purpose: formation of the amino acid conjugate would benefit naringenin from the various substituent effect as well as increased solubility. Herein we report our efforts to synthesize the title compounds. Recently, two classes of naringenin derivatives, naringenin 7-O-oleic ester and naringenin 7-O-cetyl ether, were prepared for biological evaluation of their anti-atherogenic activity by using the mixed anhydride strategy. However, in our case, due to the epimerization problem at the amino acid αcarbon under the reaction conditions, we decided to use rather mild coupling conditions which was successfully exploited for the preparation of the amino acid esters of 5,7dihydroxy-3-phenoxychromones (3, Figure 2). Thus, a mixture of naringenin (4), N-Boc-L-alanine, and DMAP in anhydrous THF or DMF was treated with EDCI (Scheme 1) and the reaction was monitored by TLC. However, the reaction did not proceed at all presumably due to the solubility problem of the naringenin. After extensive survey of the appropriate solvent system for the coupling reaction, methylene chloride (CH2Cl2) was found to be the solvent of choice: initial slurry of naringenin and NBoc-L-alanine in anhydrous CH2Cl2 became a clear solution as the reaction proceeds, and the reaction was complete in 2

Protective Conditioning for Acute Graft-versus-Host Disease

Conditioning with total lymphoid irradiation plus antithymocyte serum protects mice against acute graft-versus-host disease (GVHD) after hematopoietic-cell transplantation. We tested this strategy in humans. Thirty-seven patients with lymphoid malignant diseases or acute leukemia underwent an experimental conditioning regimen with 10 doses of total lymphoid irradiation (80 cGy each) plus antithymocyte globulin, followed by an infusion of HLA-matched peripheral-blood mononuclear cells from related or unrelated donors who received granulocyte colony-stimulating factor. Of the 37 transplant recipients, only 2 had acute GVHD after hematopoietic-cell transplantation. Potent antitumor effects in patients with lymphoid malignant diseases were shown by the change from partial to complete remission. In the transplant recipients who underwent conditioning with total lymphoid irradiation and antithymocyte globulin, the fraction of donor CD4+ T cells that produced interleukin-4 after in vitro stimulation increased by a factor of five, and the proliferative response to alloantigens in vitro was reduced, as compared with normal control subjects and control subjects who underwent conditioning with a single dose of total-body irradiation (200 cGy). A regimen of total lymphoid irradiation plus antithymocyte globulin decreases the incidence of acute GVHD and allows graft antitumor activity in patients with lymphoid malignant diseases or acute leukemia treated with hematopoietic-cell transplantation.

Role of additional angiography and chemoembolization in patients with hepatocellular carcinoma who achieved complete necrosis following transarterial chemoembolization

Although transarterial chemoembolization (TACE) has been reported to have antitumor effects in patients with hepatocellular carcinoma (HCC), optimal time schedules and follow-up methods have not yet been determined. We therefore prospectively analyzed the effects of additional angiography and chemoembolization on HCC recurrence and survival in patients who underwent TACE and achieved complete necrosis (CN). A total of 68 patients who achieved CN after TACE, as assessed using dynamic computed tomography (CT), were randomized into two groups. Patients in the CT group (n = 34) were followed using dynamic CT every 3 months without any further intervention, whereas patients in the angiography group (n = 34) received additional angiography 1 month after achievement of CN. We compared overall survival and disease-free survival between the two groups and analyzed the benefit of additional angiography. The cumulative recurrence rate did not differ between the angiography and CT groups (55%vs 48% at 12 months and 66%vs 67% at 24 months, P = 0.92). The overall survival rates at 12 and 24 months were 88% and 84% in the angiography group, and 88% and 70% in the CT group, respectively (P = 0.57). Of the 34 patients in the angiography group, 27 (79%) suffered from adverse reactions of additional angiography and subsequent chemoembolization, seven (20.6%) experienced serum bilirubin increases of >/=1 mg/dL over baseline, and two (5.9%) developed renal impairment. Additional angiography and chemoembolization did not reduce tumor recurrence or improve patient survival in HCC patients who achieved CN, as assessed using dynamic CT, following TACE.

Diphtheria toxin-epidermal growth factor fusion protein and Pseudomonas exotoxin-interleukin 13 fusion protein exert synergistic toxicity against human glioblastoma multiforme cells.

The cytotoxicity of combinations of a diphtheria toxin-human epidermal growth factor fusion protein (DAB(389)EGF) and a Pseudomonas exotoxin-human interleukin 13 fusion protein (IL13PE38QQR) was tested against 14 human glioma cell lines. After cells were cultured for 48 h with various concentrations of the fusion proteins, the percentage reductions in thymidine incorporation were determined. Seven of fourteen cell lines were highly sensitive to DAB(389)EGF alone, and six cell lines were highly sensitive to IL13PE38QQR alone with IC(90)'s < 100 pM. When combined, synergistic cell killing was observed for seven of the cell lines based upon concave isobolograms and combination indices (CI's) of 0.2 to 0.7. Supraadditive cytotoxicity was confirmed by measurements of induction of apoptosis. Receptor expression was assessed by flow cytometry and confocal microscopy. Marked heterogeneity of expression of EGFR and IL13Ralpha2 was seen on all the glioma cell lines. This heterogeneity may contribute to incomplete cell killing with the individual fusion proteins and synergistic cell kill with the combination. These results suggest that both fusion proteins may yield antitumor effects in patients with recurrent gliomas and that combination fusion protein intracranial therapy of malignant gliomas may yield an improved therapeutic index.

A phase II trial of green tea in the treatment of patients with androgen independent metastatic prostate carcinoma. Jatoi A, Ellison N, Burch PA, Sloan JA, Dakhil SR, Novotny P, Tan W, Fitch TR, Rowland KM, Young CY, Flynn PJ, Mayo Clinic and Mayo Foundation, Rochester, MN: Cancer 2003;97:1442–1446

Background Recent laboratory and epidemiologic studies have suggested that green tea has antitumor effects in patients with prostate carcinoma. This Phase II trial explored green tea’s antineoplastic effects in patients with androgen-independent prostate carcinoma. Methods This study, which was conducted by the North Central Cancer Treatment Group, evaluated 42 patients who were asymptomatic and had manifested, progressive prostate specific antigen (PSA) elevation with hormone therapy. Continued use of luteinizing hormone-releasing hormone agonist was permitted; however, patients were ineligible if they had received other treatments for their disease in the preceding 4 weeks or if they had received a long-acting antiandrogen therapy in the preceding 6 weeks. Patients were instructed to take 6 g of green tea per day orally in 6 divided doses. Each dose contained 100 calories and 46 mg of caffeine. Patients were monitored monthly for response and toxicity. Results Tumor response, defined as a decline ≥ 50% in the baseline PSA value, occurred in a single patient, or 2% of the cohort (95% confidence interval, 1–14%). This one response was not sustained beyond 2 months. At the end of the first month, the median change in the PSA value from baseline for the cohort increased by 43%. Green tea toxicity, usually Grade 1 or 2, occurred in 69% of patients and included nausea, emesis, insomnia, fatigue, diarrhea, abdominal pain, and confusion. However, six episodes of Grade 3 toxicity and one episode of Grade 4 toxicity also occurred, with the latter manifesting as severe confusion. Conclusions Green tea carries limited antineoplastic activity, as defined by a decline in PSA levels, among patients with androgen-independent prostate carcinoma. Copyright 2003 American Cancer Society.

Immunotoxin therapy of hematologic malignancies

Patients with chemotherapy relapsed or refractory hematologic malignancies may be effectively treated with allogeneic or autologous stem cell transplants. However, many patients cannot be transplanted due to age, comorbidities, or lack of suitable donors. Further, a fraction of patients relapse post-transplant. Novel therapeutic agents that can kill multidrug-resistant malignant stem cells and are not myelosuppressive are needed. One class of such agents is immunotoxins. Immunotoxins consist of cell-selective ligands covalently linked to peptide toxins. The ligand delivers the molecule to specific cell surface receptors on malignant cells. The toxin triggers cell death either by reaching the cytosol and catalytically inactivating vital cell processes or by modifying the tumor cell surface membrane. We have synthesized immunotoxins for therapy of chemoresistant hematologic diseases. In this review, we will detail the synthesis of a number of these drugs and describe their preclinical and clinical activity. Several of these agents have shown dramatic antitumor effects in patients with hematologic neoplasms, and one immunotoxin has been approved for use by the US Food and Drug Administration (FDA). Over the next several decades, a growing number of these agents should reach the clinic.

Low-intensity conditioning and hematopoietic stem cell transplantation in patients with renal and colon carcinoma.

We have evaluated whether allogeneic hematopoietic stem cell transplantation (HSCT) could induce an antitumor effect in patients with metastatic solid tumors. A total of 12 HLA-identical siblings and 6 HLA-A-, -B- and -DR beta 1-compatible unrelated grafts were used. Diagnoses were adenocarcinoma of kidney (n=10), colon (n=6), breast (n=1) and cholangiocarcinoma (n=1). Conditioning was fludarabine 30 mg/m(2)/day for 3 days and 2 Gy of total body irradiation. Recipients of unrelated HSCT were also given thymoglobuline and two additional days of fludarabine. The median CD34+ cell dose was 7.5 x 10(6)/kg. Immunosuppression was mycophenolate mofetil and cyclosporin. Among all, 12 patients became complete donor chimeras within a median of 28, 29 and 65 days for B, myeloid and T cells, respectively. Two patients rejected the grafts, one developed marrow aplasia and three were mixed chimeras. The probability of grades II-IV acute graft-versus-host-disease (GVHD) was 57%. Regression of all tumor metastases was seen in one patient with colon carcinoma. Another patient with colon and two with renal carcinoma had regression of lung metastases, but progression of metastases in the liver and/or bone. Necrosis of lung metastasis was found in one further patient with renal carcinoma who died of graft-versus-host-disease (GVHD). In all, 10 patients died; four of transplant-related complications, one of trauma and five of progressive disease. Thus, progression was common after allogeneic HSCT in unselected patients with advanced solid tumors. However, the regression of some metastases associated with GVHD provides suggestive evidence that the GVHD effect may occur in renal and colon adenocarcinoma using reduced intensity conditioning.

Somatostatin receptors in pituitary and development of somatostatin receptor subtype-selective analogs.

Somatostatin receptor (SSTR) subtypes 1, 2, and 5 are expressed in the normal human pituitary. SSTR2 and SSTR5 are expressed in almost all growth hormone (GH) cell adenomas, and prolactin (PRL)-secreting tumors express SSTR5 more than SSTR2. SSTR4 is not detected in all pituitary adenoma subtypes, and SSTR1 and SSTR3 are expressed in about 50% of tumors. Human GH is regulated through ligand binding to both SSTR2 and SSTR5, but octreotide and lanreotide, the two clinically available somatostatin analogs, bind to human SSTR2 much better than to SSTR5. Novel SSTR2- and SSTR5- selective analogs with improved binding affinity for these receptor subtypes are highly potent in suppressing GH release from cultures of human fetal pituitaries or GH-cell adenomas. Only SSTR5-selective analogs suppress in vitro PRL secretion from cultured prolactinomas. A new SSTR2+5 bispecific analog with high affinity and selectivity for both SSTR2 and SSTR5, and a somatostatin analog with a unique broad receptor (SSTR1, 2, 3, and 5) binding profile, are both able to inhibit in vitro GH release in GH cell adenomas partially sensitive to octreotide. Recently, a somatostatindopamine hybrid molecule was introduced with potentially functional synergy on GH and PRL release. Using the expanding knowledge on SSTRs and their ligand activation, the development of novel pharmacologic concepts may open new opportunities for effective manipulation of this complex intracellular signaling system. These concepts may achieve better control of pituitary hormone hypersecretion, pituitary size, as well as antitumor effects in patients with SSTR-expressing tumors.

Influence of the bystander effect on HSV-tk/GCV gene therapy. A review.

Despite the development of new therapeutic strategies, cancer remains incurable in most patients with advanced disease. A recent potential improvement in therapeutic strategies is the concept of suicide gene therapy. After transfection with a suicide gene, cells can convert a harmless prodrug into its toxic metabolite, resulting in selective elimination of these cells. One of the most frequently studied therapeutic strategies is based on transfection with the herpes simplex virus thymidine kinase gene (HSV-tk), followed by ganciclovir administration. Despite promising results in vitro and in vivo, the antitumor effect in clinical trials remains poor, due to very low transfection efficiency. However, high percentages of transfected cells are not mandatory for complete eradication of a tumor in vivo. Transfected tumor cells appear to be capable of inducing the death of neighboring untransfected cells. This cell kill is called the "bystander effect". Various attempts have been made to increase this effect. A substantial bystander effect could overcome the limitations of low transfection efficiency and result in an enhanced and possibly clinically worthwhile antitumor effect in patients. This review is focused on the HSV-tk/GCV system and gives an overview of current knowledge on the bystander effect in vitro and in vivo. In addition, theories concerning its mechanisms and possible approaches to augment this effect are discussed. Finally, we give an overview of clinical trials using suicide gene therapy.

Palliative Chemotherapy in Pretreated Patients with Advanced Cancer: Oral Trofosfamide Is Effective in Ovarian Carcinoma

Thirty-four patients with advanced cancer of various origins and documented disease progression were treated with continuous daily doses of 50–150 mg of oral trofosfamide (TRO). Of 31 evaluable patients, 5 responded to this treatment (1 complete remission and 4 partial remissions) and 12 patients had stable disease. Four of 9 patients with advanced ovarian cancer resistant to platinum-containing regimens and paclitaxel responded to oral TRO. The median treatment duration was 26 weeks for responders and 6 weeks for nonresponders, with cumulative doses of up to 46.000 mg TRO. Response duration was 11–47 weeks. No significant side effects were observed. Oral TRO given in the outpatient setting seems to be an attractive therapeutic option for heavily pretreated cancer patients, and it has remarkable antitumor effects in patients with ovarian cancer.

Transarterial Chemotherapy with Zinostatin Stimalamer for Hepatocellular Carcinoma

Zinostatin stimalamer (SMANCS) is a lipophilic intra-arterial chemotherapeutic agent for hepatocellular carcinoma (HCC). Thirty HCC patients underwent transcatheter arterial injection of 4 mg SMANCS-lipiodol emulsion. Their responses were evaluated by computed tomography 1 month after treatment. Complete response (CR) was defined as disappearance or 100% necrosis of all tumors. Partial response (PR) was defined as ≧50% reduction and/or ≧50% necrosis. We regarded the lipiodol accumulation in tumors as being necrotic. CR and PR were observed in 8 patients (27%) and 4 patients (13%), respectively, and the overall response rate (CR + PR/all patients) was 40% (12/30). Of 12 patients whose serum α-fetoprotein levels had been more than 200 ng/ml before treatment, 5 patients (42%) showed more than 50% reduction in this level within 1 month after treatment. Toxicity was quite acceptable, although grade 4 toxicity (WHO) was observed as liver dysfunction in 1 patient. Transarterial chemotherapy with SMANCS, which is well tolerated, appears to have moderate antitumor effect in patients with HCC.

Treatment of 283 Consecutive Patients With Metastatic Melanoma or Renal Cell Cancer Using High-Dose Bolus Interleukin 2

To determine the efficacy of treatment using high-dose bolus interleukin 2 (IL-2) in patients with metastatic melanoma or renal cell cancer. Consecutive series of all patients treated with high-dose IL-2 in the Surgery Branch of the National Cancer Institute from September 1985 through December 1992. Two hundred eighty-three patients with metastatic melanoma or metastatic renal cell cancer who had failed standard treatment for their cancers. Patients received IL-2 at a dose of 720,000 IU/kg intravenously every 8 hours for a maximum of 15 doses per cycle. Two cycles constituted a treatment course, and patients with stable or responding disease received additional treatment courses. A total of 447 courses of treatment were administered. Regression of measurable tumor, durability of response to treatment, and survival. Nine patients (7%) with metastatic melanoma achieved complete regression of all disease and 14 patients (10%) had partial regression. Ten patients (7%) with metastatic renal cell cancer experienced complete regression and 20 patients (13%) had partial regression. Of the 19 patients with complete regression, 15 have remained in complete remission from 7 to 91 months after treatment. Three treatment-related deaths (1.1%) occurred early in this series, but as experience with the administration of this IL-2 regimen increased, no treatment-related deaths occurred in 214 patients treated during the last 5 years of the study. Biologic therapy with IL-2 can cause significant antitumor effects in patients with advanced metastatic melanoma or renal cell cancer. Because IL-2 does not have a direct effect on cancer cells but rather mediates its antitumor activity by altering host immune reactions, these data represent the best available evidence that immunologic therapy for cancer can be effective in selected patients.