oblimersen and Neoplasms

The B-cell lymphoma/leukemia 2 (BCL-2) family of proteins has attracted the attention of cancer biologists since the cloning of BCL-2 more than 25 years ago. In the intervening decades, the way the BCL-2 family controls commitment to programmed cell death has been greatly elucidated. Several drugs directed at inhibiting BCL-2 and related antiapoptotic proteins have been tested clinically, with some showing considerable promise, particularly in lymphoid malignancies. A better understanding of the BCL-2 family has also provided insight into how conventional chemotherapy selectively kills cancer cells and why some cancers are more chemosensitive than others. Further exploitation of our understanding of the BCL-2 family promises to offer improved predictive biomarkers for oncologists and improved therapies for patients with cancer.

Topics: Aniline Compounds; Animals; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Drug Resistance, Neoplasm; Humans; Indoles; Molecular Targeted Therapy; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Sulfonamides; Thionucleotides; Treatment Outcome

Defects in apoptotic pathways can promote cancer cell survival and also confer resistance to antineoplastic drugs. One pathway being targeted for antineoplastic therapy is the anti-apoptotic B-cell lymphoma-2 (Bcl-2) family of proteins (Bcl-2, Bcl-XL, Bcl-w, Mcl-1, Bfl1/A-1, and Bcl-B) that bind to and inactivate BH3-domain pro-apoptotic proteins. Signals transmitted by cellular damage (including antineoplastic drugs) or cytokine deprivation can initiate apoptosis via the intrinsic apoptotic pathway. It is controversial whether some BH3-domain proteins (Bim or tBid) directly activate multidomain pro-apoptotic proteins (e.g., Bax and Bak) or act via inhibition of those anti-apoptotic Bcl-2 proteins (Bcl-2, Bcl-XL, Bcl-w, Mcl-1, Bfl1/A-1, and Bcl-B) that stabilize pro-apoptotic proteins. Overexpression of anti-apoptotic Bcl-2 family members has been associated with chemotherapy resistance in various human cancers, and preclinical studies have shown that agents targeting anti-apoptotic Bcl-2 family members have preclinical activity as single agents and in combination with other antineoplastic agents. Clinical trials of several investigational drugs targeting the Bcl-2 family (oblimersen sodium, AT-101, ABT-263, GX15-070) are ongoing. Here, we review the role of the Bcl-2 family in apoptotic pathways and those agents that are known and/or designed to inhibit the anti-apoptotic Bcl-2 family of proteins.

Topics: Aniline Compounds; Animals; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Gossypol; Humans; Indoles; Mitochondria; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Sulfonamides; Thionucleotides

Cancer cells show deviant behavior that induces apoptotic signaling. To survive, cancer cells typically acquire changes enabling evasion of death signals. One way they do this is by increasing the expression of anti-apoptotic BCL-2 proteins. Anti-apoptotic BCL-2 family proteins antagonize death signaling by forming heterodimers with pro-death proteins. Heterodimer formation occurs through binding of the pro-apoptotic protein's BH3 domain into the hydrophobic cleft of anti-apoptotic proteins. The BH3 mimetics are small molecule antagonists of the anti-apoptotic BCL-2 members that function as competitive inhibitors by binding to the hydrophobic cleft. Under certain conditions, antagonism of anti-apoptotic BCL-2 family proteins can unleash pro-death molecules in cancer cells. Thus, the BH3 mimetics are a new class of cancer drugs that specifically target a mechanism of cancer cell survival to selectively kill cancer cells.

Topics: Aniline Compounds; Animals; Antineoplastic Agents; Apoptosis; Benzamides; Binding, Competitive; Biphenyl Compounds; Clinical Trials as Topic; Dimerization; Drug Delivery Systems; Drug Design; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Humans; Indoles; Mice; Mitochondria; Multigene Family; Neoplasm Proteins; Neoplasms; Nitrophenols; Piperazines; Protein Structure, Tertiary; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Structure-Activity Relationship; Sulfonamides; Sulfones; Thionucleotides

Antisense oligonucleotides (ASO) against specific molecular targets (e.g., Bcl-2 and Raf-1) are important reagents in cancer biology and therapy. Phosphorothioate modification of the ASO backbone has resulted in an increased stability of ASO in vivo without compromising, in general, their target selectivity. Although the power of antisense technology remains unsurpassed, dose-limiting side effects of modified ASO and inadequate penetration into the tumor tissue have necessitated further improvements in ASO chemistry and delivery systems. Oligonucleotide delivery systems may increase stability of the unmodified or minimally modified ASO in plasma, enhance uptake of ASO by tumor tissue, and offer an improved therapy response. Here, we provide an overview of ASO design and in vivo delivery systems, and focus on preclinical validation of a liposomal nanoparticle containing minimally modified raf antisense oligodeoxynucleotide (LErafAON). Intact rafAON (15-mer) is present in plasma and in normal and tumor tissues of athymic mice systemically treated with LErafAON. Raf-1 expression is decreased in normal and tumor tissues of LErafAON-treated mice. Therapeutic benefit of a combination of LErafAON and radiation or an anticancer drug exceeds radiation or drug alone against human prostate, breast, and pancreatic tumors grown in athymic mice. Further improvements in ASO chemistry and nanoparticles are promising avenues in antisense therapy of cancer.

Topics: Animals; Antineoplastic Agents; Combined Modality Therapy; Disease Models, Animal; Drug Carriers; Gene Expression Regulation, Neoplastic; Humans; Mice; Mice, Nude; Nanoparticles; Neoplasms; Oligodeoxyribonucleotides; Oligonucleotides, Antisense; Proto-Oncogene Proteins c-bcl-2; Proto-Oncogene Proteins c-raf; Thionucleotides

Oblimersen is an antisense oligonucleotide developed by Genta for systemic use as an injection. It comprises a phosphorothioate backbone linking 18 modified DNA bases. Oblimersen targets the first six codons of Bcl-2 mRNA to form a DNA/RNA complex. The duplex is subsequently recognised as a foreign message and is cleaved enzymatically, thereby destroying the Bcl-2 message. The Bcl-2 protein, which is a potent inhibitor of apoptosis, is overexpressed in many cancers, including follicular lymphomas, breast, colon and prostate cancers, and intermediate-/high-grade lymphomas. By reducing the amount of Bcl-2 protein in cancer cells, oblimersen may enhance the effectiveness of conventional anticancer treatments. Genta has reported results from randomised phase III trials of oblimersen in four different indications: malignant melanoma, chronic lymphocytic leukaemia (CLL), multiple myeloma and acute myleoid leukaemia (AML). A negative opinion has been issued for the company's MAA for the product in the treatment of malignant melanoma in the EU; the EMEA has indicated an additional confirmatory trial is needed in this indication for approval. An NDA for CLL was deemed non-approvable by the US FDA; the company is appealing this decision. The phase III trials in multiple myeloma and AML did not meet their primary endpoints. Phase I and II trials are also underway or have been completed for a range of other cancer types. Genta and sanofi-aventis (formerly Aventis) entered into a collaboration agreement in 2002; however, this agreement was terminated by sanofi-aventis in May 2005. Genta became solely responsible for all costs relating to oblimersen at this time. Genta expanded its Cooperative Research and Development Agreement (CRADA) with the National Cancer Institute in November 2001. The expanded collaboration was to investigate the use of oblimersen in combination with standard anticancer therapy in a broad range of cancers. This expansion occurred following the Gensynergy project, which showed that oblimersen was synergistic with other anticancer therapies. Genta signed a 5-year manufacturing agreement with Avecia Ltd in December 2002 to supply it with oblimersen. Genta's NDA was submitted to the FDA in December 2005 and accepted for review in March 2006. The application was based on data from a phase I/II trial (NCT00021749) of oblimersen alone in approximately 40 patients and a phase III study (NCT00024440) of 241 patients who received fludarabine and cyclo-pho

Topics: Animals; Antineoplastic Agents; Clinical Trials as Topic; Humans; Neoplasms; Oligonucleotides, Antisense; Proto-Oncogene Proteins c-bcl-2; Thionucleotides

Regulation of cell death (apoptosis) is frequently affected in the development of malignant diseases, and all molecular steps from extracellular signalling receptors through intracellular pathways, cell death rheostats and cell death executioners may be involved. Bcl-2 is an anti-apoptotic member of a family of anti- and pro-apoptotic proteins that is upregulated in a variety of cancers and specifically overexpressed through chromosomal translocation in some non-Hodgkin lymphomas. Experimental attenuation of Bcl-2 lowers the threshold for undergoing chemotherapy-induced apoptosis. Therefore, therapeutic targeting of Bcl-2 appears as an attractive approach currently intensely explored using mRNA degradation strategies and small inhibitory molecules. One phosphorothioate oligodeoxynucleotide antisense against Bcl-2 mRNA, oblimersen (Genasense, G3139), has been used in a substantial number of clinical trials. In this review we will discuss the current developments of G3139, and scrutinize its proposed mechanism of action. Several studies indicate that G3139 involves various intracellular mechanisms and modulation of the immune system. To this date G3139 has not been justified in cancer therapy due to modest or absent effects. But, surprisingly, some of its off-target effects may represent useful therapeutic principles. Therefore, antisense uptake improvements and new design of the oligonucleotide may provide us with useful therapeutics, including both the targeted gene and new anticancer mechanisms. This may be another example of how targeted therapy molecules evolve into multimodality drugs when moved from laboratory bench to bedside use, and illustrate our limited ability for target prediction and scant understanding of biological systems when designing therapeutic strategies.

Topics: Antineoplastic Agents; Clinical Trials as Topic; Drug Resistance, Neoplasm; Humans; Neoplasms; Oligonucleotides, Antisense; Proto-Oncogene Proteins c-bcl-2; Thionucleotides

Apoptosis is a fundamental cellular death process that is essential for normal tissue homeostasis, whose deregulation is associated with several human disease states, including cancer. Increased understanding of cancer biology has led to the hypothesis that although cancer cells are inherently resistant to the engagement of apoptosis due to the deregulation of molecular components of core apoptotic machinery or of survival signalling cascades, they are primed to die as a result of microenvironmental and oncogenic proapoptotic stress. Recently, deeper insight into the molecular regulation of apoptosis and, specifically, into its deregulation in cancer has led to the development of promising therapies to restore apoptosis and enable selective tumour cell kill. It is hoped that these mechanism-based therapies will exhibit less problematic toxicity profiles than those of conventional agents. Moreover, the development of tailored therapies directed at malignancies bearing specific alterations in apoptotic or survival signalling components may be used in combination approaches to overcome the resistance to other forms of treatment.

Topics: Alkaloids; Animals; Antineoplastic Agents; Apoptosis; bcl-X Protein; Benzophenanthridines; Caspases; Clinical Trials as Topic; Drug Evaluation, Preclinical; Humans; Neoplasms; Oligonucleotides, Antisense; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-bcl-2; Receptors, Tumor Necrosis Factor; Recombinant Proteins; Signal Transduction; Thionucleotides; TNF-Related Apoptosis-Inducing Ligand; X-Linked Inhibitor of Apoptosis Protein

Topics: DNA, Antisense; Drug Delivery Systems; Drug Design; Gene Targeting; Genetic Diseases, Inborn; HIV; Humans; Intercellular Adhesion Molecule-1; Neoplasms; Proto-Oncogenes; RNA; RNA Interference; RNA, Messenger; Thionucleotides; Virus Diseases

Antisense oligonucleotides have been evaluated as antineoplastic agents in a series of clinical trials, with mixed results. However, phase III trials incorporating G3139, a phosphorothioate oligomer targeted to the initiation codon region of the bcl-2 mRNA, have recently been completed in advanced melanoma, myeloma, and chronic lymphocytic leukemia (CLL). This article discusses the mechanism of the antisense effect and its dependence on the cellular internalization of oligonucleotides and the activity of RNase H. It also describes the properties, specific and nonspecific, of phosphorothioate oligonucleotides, the predominant species in current clinical trials, and discusses pharmacokinetic data obtained from earlier phase I and II trials employing these molecules. While the application of antisense technology to the treatment of human cancer is conceptually straightforward, in practice there are many complicated, mechanistically based questions that must be considered.

Topics: Clinical Trials as Topic; Gene Silencing; Humans; Neoplasms; Oligonucleotides, Antisense; Oncogenes; Thionucleotides

The currently available treatment of cancer patients is based on the use of cytotoxic drugs and/or of ionizing radiations, which have potent antitumor activity, but also cause clinically relevant side effects, since they affect cellular targets that are common to both cancer cells and normal proliferating cells. In the past 20 years, the discoveries on the molecular mechanisms of cancer development and progression have prompted the search for agents which are more selective for cancer cell molecular targets. The possibility of combining conventional cytotoxic drugs with novel agents that specifically interfere with key pathways controlling cancer cell survival, proliferation, invasion and/or metastatic spreading has generated a wide interest. This could be a promising therapeutic approach for several reasons. First, since the cellular targets for these agents and their mechanism(s) of action are different from those of cytotoxic drugs, it is possible for their combination with chemotherapy without cross-resistance. Second, alterations in the expression and/or the activity of genes that regulate mitogenic signals not only can directly cause perturbation of cell growth, but also may affect the sensitivity of cancer cells to conventional chemotherapy and radiotherapy. In this review, we will discuss the biologic bases of the combination of molecular targeted drugs with conventional medical cancer treatments and the available results of the first series of clinical trials in cancer patients.

Topics: Alkyl and Aryl Transferases; Antineoplastic Agents; Combined Modality Therapy; ErbB Receptors; Farnesyltranstransferase; Genes, bcl-2; Humans; Neoplasms; Oligodeoxyribonucleotides, Antisense; Oligonucleotides; Protein Kinase C; ras Proteins; Signal Transduction; Thionucleotides

Apoptosis, or programmed cell death, is a complex process of cell turnover involved in both normal and pathologic processes in the body. Impairments in the apoptotic pathways contribute to tumorigenesis and the development of tumor resistance to chemotherapy. The proto-oncogene bcl-2 appears to serve a critical antiapoptotic function. Its broad expression in tumors coupled with its role in resistance to chemotherapy-induced apoptosis make bcl-2 a rational target for anticancer therapy. The Bcl-2 antisense drug oblimersen sodium (Genasense) enhances apoptosis alone and in combination with cytotoxic chemotherapy in vitro and in numerous xenograft models of solid tumors and hematologic cancers. Results from xenograft models of melanoma were especially encouraging, prompting melanoma to be identified as an initial human trial candidate. In a phase II trial in patients with advanced malignant melanoma resistant to first-line chemotherapy (including dacarbazine [DTIC-Dome]), three objective responses and three minor responses to oblimersen plus dacarbazine were observed among 14 patients. In a large randomized phase III trial, oblimersen plus dacarbazine showed a near doubling of response rate vs dacarbazine alone and a significant prolongation of progression-free survival. For the primary endpoint of overall survival, a significant benefit for the combination was not seen. The ability of oblimersen to modulate apoptosis suggests a new paradigm of anticancer therapy that has clinical potential in a variety of solid tumors and hematologic malignancies. Further, oblimersen is the first antisense molecule studied in clinical trials for its anticancer properties, opening up an entirely new direction for therapy.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Clinical Trials, Phase II as Topic; Clinical Trials, Phase III as Topic; Dacarbazine; Genes, bcl-2; Humans; Melanoma; Neoplasms; Oligonucleotides, Antisense; Proto-Oncogene Mas; Proto-Oncogene Proteins c-bcl-2; Randomized Controlled Trials as Topic; Thionucleotides; Transplantation, Heterologous

Cancer cells that express excessive levels of Bcl-2 pose a major problem in the delivery of curative therapy. Most treatments for such cancer involve chemotherapy to induce the apoptotic process. While these therapies often result in disease control for periods of time, failure to initiate apoptosis as a result of acquired resistance limits the effectiveness of treatment for many common hematopoietic and solid malignancies, and ultimately death from the malignancy still occurs. Various anti-apoptotic proteins of the Bcl-2 family that localize to the mitochondria appear to be involved in this resistance mechanism. However, recent advances in the understanding of malignant cell biology, achieved through both genomics and proteomics, have made it possible to explore novel approaches directed at re-establishing sensitivity to chemotherapy, presenting an attractive strategy for cancer treatment. In this article we discuss how this may be achieved by lowering Bcl-2 anti-apoptotic protein expression using antisense oligonucleotides or, alternatively, by functionally antagonizing Bcl-2 using ligands of the mitochondrial benzodiazepine receptor.

Topics: Animals; Antineoplastic Agents; Apoptosis; Down-Regulation; Gene Expression Regulation, Neoplastic; Genes, bcl-2; Humans; Neoplasms; Oligonucleotides, Antisense; Pectins; Proto-Oncogene Proteins c-bcl-2; Thionucleotides

The regulation of apoptosis is an important potential target for anticancer therapy. The mitochondrial Bcl-2 protein inhibits apoptosis and is therefore an important mediator of resistance to treatment with traditional cytotoxic chemotherapy, radiotherapy and monoclonal antibody therapy. Oblimersen (Genasense, Aventis Pharmaceuticals / Genta Inc) is a 18mer antisense-oligonucleotide (ASO), which specifically binds to the first 6 codons of the human bcl-2 mRNA, resulting in degradation and destruction of the mRNA by RNAse H. Subsequently there is a significant decrease of bcl-2 translation. A growing number of preclinical and clinical studies suggests that the combination of cytotoxic therapy with Oblimersen results in synergistic anticancer efficacy in many hematologic and solid tumors. Due to its low toxicity profile, oblimersen is an ideal combination partner with conventional chemotherapy. Three randomized phase-III trials (malignant melanoma, chronic lymphocytic leukemia, multiple myeloma) have recently finished recruitment. The results of these studies will be available by the end of 2003. Based on preclinical data, a lot of nonrandomized phase-II studies on several different tumor types like AML, CML, NHL, prostate cancer and breast cancer are underway. The manipulation of proapoptotic and antiapoptotic factors in favor of proapoptotic factors by inhibition of the bcl-2 protein translation in order to enhance the efficacy of anticancer treatments represents a promising new treatment concept in oncology.

Topics: Animals; Apoptosis; Clinical Trials as Topic; Drug Evaluation, Preclinical; Female; Humans; Male; Neoplasms; Oligonucleotides, Antisense; Proto-Oncogene Proteins c-bcl-2; Thionucleotides; Treatment Outcome; Tumor Cells, Cultured

For the majority of patients with advance malignancies, current therapies are noncurative. Developing therapeutic agents that enhance the apoptotic effects and hence antitumor potential of currently available chemotherapy agents represents a rationale investigative strategy. Several chemotherapeutic agents including antimicrotubule agents and all-trans-retinoic acid utilize these pathways to mediate tumor cell killing. With specific agents such as oblimersan sodium in randomized "pivotal" studies, and agents targeting the TRAIL receptor-family recently entering early clinical study, cautious optimism is warranted.

Topics: Antineoplastic Agents; Apoptosis; Apoptosis Regulatory Proteins; Clinical Trials as Topic; Drug Design; Genes, bcl-2; Humans; Membrane Glycoproteins; Models, Biological; Neoplasm Proteins; Neoplasms; Oligodeoxyribonucleotides, Antisense; Proto-Oncogene Proteins c-bcl-2; Recombinant Proteins; Thionucleotides; TNF-Related Apoptosis-Inducing Ligand; Tretinoin; Tumor Necrosis Factor-alpha

Topics: Animals; Antineoplastic Agents; Humans; Lymphoma, Non-Hodgkin; Male; Melanoma; Neoplasms; Oligonucleotides, Antisense; Prostatic Neoplasms; Thionucleotides

There is a potential role for antisense oligonucleotides in the treatment of disease. The principle of antisense technology is the sequence-specific binding of an antisense oligonucleotide to target mRNA, resulting in the prevention of gene translation. The specificity of hybridisation makes antisense treatment an attractive strategy to selectively modulate the expression of genes involved in the pathogenesis of diseases. One antisense drug has been approved for local treatment of cytomegalovirus-induced retinitis, and several antisense oligonucleotides are in clinical trials, including oligonucleotides that target the mRNA of BCL2, protein-kinase-C alpha, and RAF kinase. Antisense oligonucleotides are well tolerated and might have therapeutic activity. Here, we summarise treatment ideas in this field, summarise clinical trials that are being done, discuss the potential contribution of CpG motif-mediated effects, and look at promising molecular targets to treat human cancer with antisense oligonucleotides.

Topics: Animals; Antineoplastic Agents; Clinical Trials as Topic; Drug Design; Humans; In Vitro Techniques; Isoenzymes; Neoplasms; Oligodeoxyribonucleotides, Antisense; Oligonucleotides; Oligonucleotides, Antisense; Phosphorothioate Oligonucleotides; Protein Kinase C; Protein Kinase C-alpha; Proto-Oncogene Proteins c-bcl-2; RNA, Messenger; Thionucleotides

Genasense (formerly known as G-3139), an antisense oligonucleotide specific for Bcl-2, is under development by Genta as an iv drip infusion for the potential treatment of various cancers including melanoma, prostate, breast and colon cancer [3083751. It is in phase III trials for malignant melanoma, for which it has been awarded Fast Track status 1359044]. Genasense received Orphan Drug status in August 2000 [3782331. In September 2000, the company announced that pivotal phase III trials in multiple melanoma, chronic lymphocytic leukemia (CLL) and acute myelocytic leukemia (AML) would be underway by 2001 [382783]. By January 2001, trials in AML and CLL had been initiated 1396512]. As of February 2001, Genta was planning the initiation of two additional, registration quality trials. Pending positive results from these trials, launch of Genasense is anticipated in 2002 13984111. A phase III trial in patients with advanced multiple myeloma at 65 centers in the US, Canada and Great Britain began in February 2001. The trial will examine whether the addition of Genasense can improve response rates, response duration and quality of life compared with dexamethasone therapy alone 13989081. Genta Inc has been issued a patent (US-05831066) for Genasense 1283005]. The patent provides protection to Genta for the composition of Genasense and its analogs. Furthermore, Genta Inc has also been issued two new patents that cover a series of compounds containing new backbone constructions that enhance the antisense affinity of the drug to the target pre-RNA, while the other patent covers the methods for preparation of antisense oligonucleotides containing the new backbone structures 12896851. Genta has already licensed the rights for the use of Bd-2 as a target for antisense- and gene therapy-based treatments from The University of Pennsylvania. The licensing agreements with Chugai Pharmaceutical Co for worldwide marketing and profit sharing places Genta in a favorable position. In January 2001, Needham & Co expected Genasense to have a potential market of 47,700 malignant melanoma patients in the US. The analysts also expected potential patient market sizes of 50,000 (CLL), 21,000 (AML), 136,000 (non-small cell lung cancer; NSLCC) and 180,000 (prostate cancer) in the US. In addition, the analysts predicted that Genasense would be approved for melanoma in the second quarter of 2002, with approvals to follow for CLL (third quarter of 2002), AML (third quarter of 2002) and mye

Topics: Antineoplastic Agents; Clinical Trials as Topic; Humans; Neoplasms; Oligonucleotides, Antisense; Proto-Oncogene Proteins c-bcl-2; Thionucleotides

Overexpression of Bcl-2 is associated with worse prognosis for a number of cancer types. The present study was designed to determine the maximum tolerated dose (MTD) of oblimersen (antisense Bcl-2) and gemcitabine when administered to patients with refractory malignancies.. Sixteen patients with advanced solid tumors refractory to standard therapies were treated with escalating doses of oblimersen continuous, 120-h intravenous infusion given every 14 days, with a fixed-dose-rate intravenous infusion of gemcitabine administered on day 5 of each cycle. Serial plasma samples were collected to calculate the pharmacokinetics of oblimersen and gemcitabine, and also to measure the effect of oblimersen on Bcl-2 expression.. 7 women and 9 men, median age 55 years (range 35-74 years), received a 5-day infusion of oblimersen at dose levels of 5 mg/kg/day (n = 4) or 7 mg/kg/day (n = 12). On the 5th day of the infusion, gemcitabine was given at 10 mg/m(2)/h for a total dose of 1,000 mg/m(2) (n = 7; cohorts I and II), 1,200 mg/m(2) (n = 3; cohort III), or 1,500 mg/m(2) (n = 6; cohort IV). Edema was the dose-limiting toxicity (DLT), necessitating expansion of cohort IV. No subsequent DLTs were noted. Thus, the maximum planned doses were well tolerated, and a formal MTD was not determined. Most hematologic toxicities were grade 1 or 2. There was low-grade fatigue, nausea/vomiting, and myalgias/arthralgias. Oblimersen C(ss) and AUC increased in relation to the dose escalation, but gemcitabine triphosphate levels did not correlate well with dose. There were no objective responses, though 5 patients had stable disease. A >75% reduction in Bcl-2 expression in peripheral blood mononuclear leucocytes was seen more frequently in patients who achieved stable disease than in progressing patients.. The maximal planned dose levels of oblimersen and gemcitabine in combination were well tolerated. Only one DLT (edema) occurred. There was a correlation between Bcl-2 reduction and stable disease. The recommended doses of the drugs for future studies are 7 mg/kg/day of oblimersen on days 1-5, and gemcitabine 1,500 mg/m(2) on day 5, every two weeks.

Topics: Adult; Aged; Antineoplastic Agents; Cohort Studies; Deoxycytidine; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Female; Gemcitabine; Genes, bcl-2; Humans; Male; Middle Aged; Neoplasm Staging; Neoplasms; Oligonucleotides, Antisense; Thionucleotides; Treatment Outcome

This phase I trial assessed the safety and tolerability of G3139 when given in combination with carboplatin and paclitaxel chemotherapy. The effect of G3139 treatment on Bcl-2 expression in peripheral blood mononuclear cells (PBMC) and paired tumor biopsies was also determined.. Patients with advanced solid malignancies received various doses of G3139 (continuous i.v. infusion days 1-7), carboplatin (day 4), and paclitaxel (day 4), repeated in 3-week cycles, in a standard cohort-of-three dose-escalation schema. Changes in Bcl-2/Bax transcription/expression were assessed at baseline and day 4 (prechemotherapy) in both PBMCs and paired tumor biopsies. The pharmacokinetic interactions between G3139 and carboplatin/paclitaxel were measured.. Forty-two patients were evaluable for safety analysis. Primary toxicities were hematologic (myelosuppression and thrombocytopenia). Dose escalation was stopped with G3139 at 7 mg/kg/d, carboplatin at area under the curve of 6, and paclitaxel at 175 mg/m(2) due to significant neutropenia seen in cycle 1 and safety concerns in further escalating chemotherapy in this phase I population. With G3139 at 7 mg/kg/d, 13 patients underwent planned tumor biopsies, of which 12 matched pairs were obtained. Quantitative increases in intratumoral G3139 with decreases in intratumoral Bcl-2 gene expression were seen. This paralleled a decrease in Bcl-2 protein expression observed in PBMCs.. Although the maximal tolerated dose was not reached, the observed toxicities were consistent with what one would expect from carboplatin and paclitaxel alone. In addition, we show that achievable intratumoral G3139 concentrations can result in Bcl-2 down-regulation in solid tumors and PBMCs.

Topics: Antineoplastic Combined Chemotherapy Protocols; bcl-2-Associated X Protein; Carboplatin; Combined Modality Therapy; Down-Regulation; Female; Gene Expression; Genes, bcl-2; Humans; Male; Neoplasms; Oligonucleotides, Antisense; Paclitaxel; Proto-Oncogene Proteins c-bcl-2; Thionucleotides

G3139 is a BCL-2 antisense oligonucleotide whose antitumor effects in preclinical models are enhanced when combined with taxane-based chemotherapy. This trial determined the safety and biologic activity of G3139 given with paclitaxel and docetaxel for the treatment of progressive solid tumors. Three cohorts of patients received weekly paclitaxel 100 mg/m2 on days 1, 8, and 15 concurrently with a 21-day continuous infusion of G3139 at 4.1, 5.3, and 6.9 mg/kg/d, depending on the cohort. Two subsequent cohorts received docetaxel (75 mg/m2) on day 5 of a 5-day infusion of G3139 at 5 or 7 mg/kg/d. Bcl-2 protein levels in peripheral blood mononuclear cells (PBMCs) were assayed on an exploratory basis. Fifteen patients were treated. Eight received a total of 14 cycles of G3139 and paclitaxel; seven received a total of 22 cycles of G3139 and docetaxel. Eight patients required dose modifications for either grade 4 neutropenia (6 patients) or grade 1-2 reversible transaminitis (2 patients). No radiographic responses were seen, although two of the six taxane-naive prostate cancer patients exhibited a prostate-specific antigen decline greater than 50%. Bcl-2 protein levels in PBMCs declined with treatment as assessed by immunohistochemistry. The authors conclude that G3139, whether given as a 5- or 21-day infusion, is well tolerated with taxane chemotherapy and is biologically active by immunohistochemistry at doses up to and including 7 mg/kg/d, using weekly paclitaxel (100 mg/m2) or docetaxel every 3 weeks (75 mg/m2). These data support the dose selection of ongoing phase 2 studies of G3139 at 7 mg/kg/d and docetaxel 75 mg/m2.

Topics: Aged; Antineoplastic Agents; Bridged-Ring Compounds; Drug Administration Schedule; Humans; Infusions, Intravenous; Male; Middle Aged; Neoplasms; Taxoids; Thionucleotides

Expression of the Bcl-2 protein confers resistance to various apoptotic signals. G3139 [oblimersen sodium (Genasense)] is a phosphorothioate antisense oligodeoxynucleotide that targets Bcl-2 mRNA, downregulates Bcl-2 protein translation, and enhances the antitumor effects of subtherapeutic doses of docetaxel (Taxotere).. We performed a phase I trial to determine the maximum tolerated dose (MTD) and safety profile of combined therapy with G3139 and weekly docetaxel in patients with advanced Bcl-2-positive solid tumors. Cohorts of three to six patients were enrolled to escalating doses of G3139 and a fixed dose of weekly docetaxel using either of two schedules. In part I, G3139 was administered by continuous infusion for 21 days (D1-22), and docetaxel (35 mg/m2) was given weekly on days 8, 15 and 22. In part II, G3139 was given by continuous infusion for 5 days before the first weekly dose of docetaxel, and for 48 h before the second and third weekly docetaxel doses. For both schedules, cycles were repeated every 4 weeks.. Twenty-two patients were enrolled. Thirteen patients were treated on the part I schedule with doses of G3139 escalated from 1 to 4 mg/kg/day. Nine patients were on the part II schedule of shorter G3139 infusion at G3139 doses of 5-9 mg/kg/day. Hematologic toxicities were mild, except for one case of persistent grade 3 thrombocytopenia in part I. The most common adverse events were cumulative fatigue and transaminase elevation, which prevented further dose escalation beyond 4 mg/kg/day for 21 days with the part I schedule. In part II of the study, using the abbreviated G3139 schedule, even the highest daily doses were tolerated without dose-limiting toxicity or the need for dose modification. Objective tumor response was observed in two patients with breast cancer, including one whose cancer previously progressed on trastuzumab plus paclitaxel. Four patients had stable disease. Pharmacokinetic results for G3139 were similar to those of other trials.. G3139 in combination with standard-dose weekly docetaxel was well tolerated. The shortened and intermittent G3139 infusion had less cumulative toxicities and still allowed similar total G3139 delivery as the longer infusion. Further studies should examine the molecular effect of the regimen, as well as clinical activities in malignancies for which taxanes are indicated.

Topics: Adult; Aged; Antineoplastic Agents, Phytogenic; Breast Neoplasms; Docetaxel; Drug Administration Schedule; Female; Humans; Infusions, Intravenous; Maximum Tolerated Dose; Middle Aged; Neoplasms; Taxoids; Thionucleotides; Treatment Outcome

To evaluate the safety and pharmacokinetics of BCL-2 antisense oligonucleotide (G3139) administered by prolonged i.v. infusion in patients with advanced cancer.. A total of 35 patients was treated in cohorts of 3-6 with 0.6-6.9 mg/kg/day of BCL-2 antisense oligonucleotide as a continuous infusion for 14 or 21 days. Plasma levels of intact antisense oligonucleotide were measured in all patients.. G3139 was generally well tolerated. At the highest dose level examined in this study (6.9 mg/kg/day), fatigue and transient reversible elevations of serum transaminases (grades 2-3) became apparent after >or=7 days of treatment. Both reactions were believed to be drug related. Pharmacokinetic analyses showed that steady-state plasma concentrations of G3139 were reached approximately 10 h after starting the infusion and increased linearly across the range of doses administered

Topics: Adult; Aged; Aged, 80 and over; Antineoplastic Agents; Biological Availability; Blotting, Western; Cohort Studies; Dose-Response Relationship, Drug; Genes, bcl-2; Half-Life; Humans; Infusions, Intravenous; Middle Aged; Neoplasms; Oligonucleotides, Antisense; Proto-Oncogene Proteins c-bcl-2; Safety; Thionucleotides; Transaminases

With the advent of advanced tools in molecular biology, understanding on cancer etiology has improved. siRNA can be considered as an effective tool in cancer therapy through silencing overexpressed genes responsible for cell proliferation or preventing apoptosis. However, some contentious issues such as stability and delivery of siRNA are to be resolved. Bcl-2, an anti-apoptotic gene, is overexpressed in a wide variety of cancers and responsible for drug resistance tumors. In our earlier studies, we developed a nanoformulation of siRNA targeting the Bcl-2 and achieved successful delivery in vitro and in vivo. To extend the scope of the study further, in the present work, we studied the role of nanoformulation of siRNA as adjuvant in chemotherapy with cisplatin. Dose dependant nephrotoxicity is a serious concern apart from other adverse effects of cisplatin. The IC(50) value for cisplatin was decreased from 9.83 μmol/l to 7.43 μmol/l in HeLa cells and from 8.54 μmol/l to 6.68 μmol/l in HEp-2 cells, when it was given with siRNA nanoformulation. Cisplatin at the dose of 1.7 mg/kg in combination with siRNA nanoformulation was effective in improving the lifespan of tumor bearing mice with significant decrease in nephrotoxicity.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Chemotherapy, Adjuvant; Cisplatin; Combined Modality Therapy; HeLa Cells; Hep G2 Cells; Humans; Mice; Neoplasms; Proto-Oncogene Proteins c-bcl-2; RNA, Small Interfering; Thionucleotides

Transferrin (Tf) conjugated lipopolyplexes (LPs) carrying G3139, an antisense oligonucleotide for Bcl-2, were synthesized and evaluated in Tf receptor positive K562 erythroleukemia cells and then in a murine K562 xenograft model.. Particle size and Zeta potentials of transferrin conjugated lipopolyplexs containing G3139 (Tf-LP-G3139) were measured by Dynamic Light Scattering and ZetaPALS. In vitro and in vivo sample's Bcl-2 downregulation was analyzed using Western blot and tumor tissue samples also exhibited by immunohistochemistry method. For athymic mice bearing with K562 xenograft tumors, tumor growth inhibition and survival rate were investigated. Nanoparticle distribution in 3-D cell cluster was observed by Laser scan confocal microscopy. IL-12 production in the plasma was measured by ELISA kit.. In vitro, Tf-LP-G3139 was more effective in inducing down regulation of Bcl-2 in K562 cells than non-targeted LP-G3139, free G3139 and mismatched control ODN-G4126 in the same formulation. In vivo Tf-LP-G3139 was less effective than free G3139 in Bcl-2 down regulation. 3-D cell cluster model diffusion results indeed indicated limited penetration of the LPs into the cell cluster. Finally, the therapeutic efficacies of Tf-LP-G3139 and free G3139 were determined in the K562 xenograft model. Tf-LP-G3139 showed slower plasma clearance, higher AUC, and greater accumulation in the tumor compared to free G3139. In addition, Tf-LP-G3139 was found to be more effective in tumor growth inhibition and prolonging mouse survival than free G3139. This was associated with increased spleen weight and IL-12 production in the plasma.. The role of the immune system in the therapeutic response obtained with the Tf-LPs is necessary and in vitro 3-D cell cluster model can be a potential tool to evaluate the nanoparticle distribution.

Topics: Animals; Cell Line, Tumor; Down-Regulation; Drug Carriers; Humans; Lipids; Mice; Mice, Inbred ICR; Mice, Nude; Nanoparticles; Neoplasms; Proto-Oncogene Proteins c-bcl-2; Receptors, Transferrin; Thionucleotides; Transfection; Transferrin

The antisense drug G3139 (oblimersen sodium, Genta, Inc.) is a phosphorothioate oligodeoxynucleotide (ODN) containing unmethylated CpG units, which is targeted to suppress Bcl-2. To date, its effectiveness in cancer clinical trials has been minimal. Some suggestions are provided for that disappointment and recent citations are provided that support the idea that G3139 may be effective at clearing viral infections, specifically HIV. At the time G3139 was conceived as an anti-cancer drug candidate, it was viewed optimistically because Bcl-2 was widely believed to be the most important protein blocking p53-dependent apoptosis caused by internal stress. Since that time, we have learnt that Bcl-2 is not the only protein that inhibits apoptosis and that p53 itself is frequently malfunctioning in tumors. Thus, the anti-cancer utility of suppressing Bcl-2 in cancer cells is limited. Moreover, Bcl-2 has a role in halting the cell cycle (though p27), which may slow down tumor growth; and Bcl-2 even has pro-apoptotic roles in the execution of apoptosis initiated by external death signals (via Fas/CD95 and caspase 3). Overall, in the clinical setting, G3139 usually has statistically significant but medically unimportant benefit. These results have greatly diminished the enthusiasm for the drug especially when the side effects are considered. Specifically, the unmethylated CpG ODN (and/or the phosphorothioate group) activates the immune system, but this potentially important anti-cancer effect is lost when the immune cells undergo premature apoptosis apparently because their Bcl-2 levels have been lowered by the antisense effect of G3139. While this effect on immune cells is usually undesirable, it is exactly what would be useful for activating immune cells, initiating provirus transcription in retrovirus-infected cells, and facilitating selective apoptosis of these infected cells. In general, G3139 might have benefit in clearing chronic infections by intracellular parasites including viruses (HIV, SIV, HTLV, HBV, coronavirus, etc.). Indeed, G3139 has been shown to cause apoptosis in EBV-infected cells leading to clearance of the virus.

Topics: Animals; Anti-HIV Agents; Apoptosis; Clinical Trials as Topic; Genes, p53; HIV Infections; Humans; Immune System; Models, Biological; Mutation; Neoplasms; Oligonucleotides, Antisense; Proto-Oncogene Proteins c-bcl-2; Thionucleotides; Treatment Outcome

Several phosphorothioate antisense oligodeoxynucleotides (ODN) are developed to target factors potentially involved in tumor growth and apoptosis suppression. Among them, the 18-mer G3139 (Oblimersen), which targets Bcl-2, is currently being tested in phase II and phase III clinical trials for various tumors in combination with chemotherapy. On the other hand, ODNs containing CpG dinucleotides (CpG-ODN) within specific-sequence contexts (CpG motifs) have been shown to activate rodent or primate immune cells via toll-like receptor 9 (TLR9) and have demonstrated remarkable T cell-dependent antitumor efficacy in a series of murine tumor models. However, immune cell activation by CpG-ODN is largely diminished upon C-5 methylation at CpG cytosine. As G3139 contains CpG motifs, we questioned whether the antitumor effects seen in human tumor xenografts might be abrogated by cytosine C-5 methylation of G3139, which retained the ability of G3139 to suppress Bcl-2 expression in tissue culture, or by similar derivatization of other phosphorothioate ODNs developed for the immune activation of rodent or human cells. The in vivo antitumor efficacy of the immunostimulatory H1826 and H2006 ODNs was compared with that of G3139. Bcl-2 suppression achieved by G3139 purportedly sensitizes tumor cells toward cytotoxic agents, and some of the experiments employed combinations of ODN with such drugs as cisplatin or etoposide. H1826, H2006, and G3139 all produced similar, striking, growth inhibitory effects on either H69 SCLC, A2780 ovarian carcinoma, or A549 lung adenocarcinoma human tumor xenografts at doses of 0.3 mg/kg and 1 mg/kg (H1826, H2006) or 12 mg/kg (G3139) per day. In contrast, the H2006-mC (1 mg/kg) or G3139-mC (12 mg/kg) derivatives demonstrated no significant antitumor effects. The combination of G3139 (12 mg/kg) with cisplatin produced some additive antitumor efficacy, which was not seen in combinations of G3139-mC (12 mg/kg) or H1826 (1 mg/kg) with cisplatin. G3139, at a dose of 12 mg/kg, alone induced extensive enlargement of the spleen. Immunostimulation was evaluated in vitro by flow cytometric measurements of the CD80 and CD86 activation markers found on CD19+ murine splenocytes. The CpG-ODN producing strong antitumor effects in vivo also induced these activation markers in vitro, in contrast to the in vivo inactive G3139-mC. Our data indicate a significant contribution of the immunostimulatory properties of CpG-ODN (including G3139) to the antitumor effect

Topics: Adenocarcinoma; Adjuvants, Immunologic; Animals; Antineoplastic Agents; B-Lymphocytes; Carcinoma; Cell Line, Tumor; Cytosine; Female; Humans; Lung Neoplasms; Lymphocyte Activation; Methylation; Mice; Mice, Nude; Neoplasms; Oligodeoxyribonucleotides; Ovarian Neoplasms; Proto-Oncogene Proteins c-bcl-2; Thionucleotides; Xenograft Model Antitumor Assays

Here, we investigated the role of telomerase on Bcl-2-dependent apoptosis. To this end, the 4625 Bcl-2/Bcl-xL bispecific antisense oligonucleotide and the HA14-1 Bcl-2 inhibitor were used. We found that apoptosis induced by 4625 oligonucleotide was associated with decreased Bcl-2 protein expression and telomerase activity, while HA14-1 triggered apoptosis without affecting both Bcl-2 and telomerase levels. Interestingly, HA14-1 treatment resulted in a profound change from predominantly nuclear to a predominantly cytoplasmic localization of hTERT. Downregulation of endogenous hTERT protein by RNA interference markedly increased apoptosis induced by both 4625 and HA14-1, while overexpression of wild-type hTERT blocked Bcl-2-dependent apoptosis in a p53-independent manner. Catalytically and biologically inactive hTERT mutants showed a similar behavior as the wild-type form, indicating that hTERT inhibited the 4625 and HA14-1-induced apoptosis regardless of telomerase activity and its ability to lengthening telomeres. Finally, hTERT overexpression abrogated 4625 and HA14-1-induced mitochondrial dysfunction and nuclear translocation of hTERT. In conclusion, our results demonstrate that hTERT is involved in mitochondrial apoptosis induced by targeted inhibition of Bcl-2.

Topics: Apoptosis; Benzopyrans; Blotting, Western; Cell Line, Tumor; DNA-Binding Proteins; Genes, p53; HCT116 Cells; Humans; Mitochondria; Neoplasms; Nitriles; Proto-Oncogene Proteins c-bcl-2; Telomerase; Thionucleotides; Transfection

Topics: Animals; Antineoplastic Agents; Apoptosis; Biphenyl Compounds; Cytochromes c; Drugs, Investigational; Glycolysis; Hexanones; Humans; Mitochondria; Mitochondrial Proton-Translocating ATPases; Neoplasms; Nitrophenols; Piperazines; Proto-Oncogene Proteins c-bcl-2; Sulfonamides; Thionucleotides

G-3139 is an antisense phosphorothioate oligodeoxynucleotide (AS PS ON) which suppresses bcl-2 expression and is being developed by Genta Inc for the potential treatment of various cancers [308375]. G-3139 is in various stages of phase I/lIa trials. One study, initiated in May 1999, at the Lombardi Cancer Center at Georgetown University Medical Center, US, will examine G-3139 in conjunction with docetaxel. In a phase I/IIa dose-escalating trial to treat non-Hodgkin's lymphoma (NHL), at the Royal Marsden NHS Trust, UK, no serious, clearly drug-attributable or doselimiting adverse effects were noted and in some patients encouraging signs of potential drug activity were observed. The responses included one patient in whom cancer mass was reduced and one who developed a complete response for over 38 weeks in duration [239159,291608,325262]. A new phase II protocol using G-3139 combined with standard chemotherapies in relapsed NHL patients has also begun [325262]. Other phase I/lIa studies include: the safety and efficacy of G-3139 in the treatment of hormone-resistant, metastatic prostate cancer, when administered with mitoxantrone [305822]; the treatment of relapsed follicular NHL, when administered with cyclophosphamide [311217]; the treatment of Stage III and IV metastatic malignant melanoma in combination with dacarbazine [289755]; the treatment of hormone-resistant, metastatic prostate cancer when administered over a significantly longer duration than studied previously and in combination with an androgen-receptor blocking agent [291608]. The National Cancer Institute (NCI) funded and conducted preclinical studies of G-3139 in July 1996 and in June 1998, the NCI and Genta entered into a Cooperative Research and Development Agreement (CRADA) for the development of G-3139 [290153]. Clinical trials,focusing on colorectal cancer, small cell lung cancer and leukemia, were underway as of April 1999. The company licensed the rights for the use of bcl-2 as a target for antisense and gene therapy-based treatments from the University of Pennnsylvania. In June 1998, Genta received two patents relating to its antisense compounds [289685].

Topics: Androgen Antagonists; Animals; Antineoplastic Agents, Hormonal; Antineoplastic Combined Chemotherapy Protocols; Cancer Care Facilities; Clinical Trials, Phase I as Topic; Clinical Trials, Phase II as Topic; Cyclophosphamide; Dacarbazine; Docetaxel; Female; Genes, bcl-2; Genetic Therapy; Humans; Male; Mice; Mice, Inbred BALB C; National Institutes of Health (U.S.); Neoplasm Proteins; Neoplasms; Paclitaxel; Patents as Topic; Proto-Oncogene Proteins c-bcl-2; RNA, Messenger; RNA, Neoplasm; Safety; Structure-Activity Relationship; Taxoids; Thionucleotides; Treatment Outcome; United States