Testicular disposition of clofarabine in rats is dependent on equilibrative nucleoside transporters.

Acute lymphoblastic leukemia (ALL) is the most common cancer in children and adolescents. Although the 5-year survival rate is high, some patients respond poorly to chemotherapy or have recurrence in locations such as the testis. The blood-testis barrier (BTB) can prevent complete eradication by limiting chemotherapeutic access and lead to testicular relapse unless a chemotherapeutic is a substrate of drug transporters present at this barrier. Equilibrative nucleoside transporter (ENT) 1 and ENT2 facilitate the movement of substrates across the BTB. Clofarabine is a nucleoside analog used to treat relapsed or refractory ALL. This study investigated the role of ENTs in the testicular disposition of clofarabine. Pharmacological inhibition of the ENTs by 6-nitrobenzylthioinosine (NBMPR) was used to determine ENT contribution to clofarabine transport in primary rat Sertoli cells, in human Sertoli cells, and across the rat BTB. The presence of NBMPR decreased clofarabine uptake by 40% in primary rat Sertoli cells (p = .0329) and by 53% in a human Sertoli cell line (p = .0899). Rats treated with 10 mg/kg intraperitoneal (IP) injection of the NBMPR prodrug, 6-nitrobenzylthioinosine 5'-monophosphate (NBMPR-P), or vehicle, followed by an intravenous (IV) bolus 10 mg/kg dose of clofarabine, showed a trend toward a lower testis concentration of clofarabine than vehicle (1.81 ± 0.59 vs. 2.65 ± 0.92 ng/mg tissue; p = .1160). This suggests that ENTs could be important for clofarabine disposition. Clofarabine may be capable of crossing the human BTB, and its potential use as a first-line treatment to avoid testicular relapse should be considered.

Delivering Antisense Oligonucleotides across the Blood-Brain Barrier by Tumor Cell-Derived Small Apoptotic Bodies.

The blood-brain barrier (BBB) is the most restrictive and complicated barrier that keeps most biomolecules and drugs from the brain. An efficient brain delivery strategy is urgently needed for the treatment of brain diseases. Based on the studies of brain-targeting extracellular vesicles (EVs), the potential of using small apoptotic bodies (sABs) from brain metastatic cancer cells for brain-targeting drug delivery is explored. It is found that anti-TNF-α antisense oligonucleotide (ASO) combined with cationic konjac glucomannan (cKGM) can be successfully loaded into sABs via a transfection/apoptosis induction process and that the sABs generated by B16F10 cells have an extraordinarily high brain delivery efficiency. Further studies suggest that ASO-loaded sABs (sCABs) are transcytosed by b. End3 (brain microvascular endothelial cells, BMECs) to penetrate the BBB, which is mediated by CD44v6, and eventually taken up by microglial cells in the brain. In a Parkinson's disease (PD) mouse model, sCABs dramatically ameliorate PD symptoms via the anti-inflammatory effect of ASO. This study suggests that sABs from brain metastatic cancer cells are excellent carriers for brain-targeted delivery, as they have not only an extraordinary delivery efficiency but also a much higher scale-up production potential than other EVs.

pH-Dependent 5-Aminosalicylates Releasing Preparations Do Not Affect Thiopurine Metabolism.

BACKGROUND/AIMS: Thiopurines are key drugs in maintenance therapy for treating inflammatory bowel disease (IBD). Time-dependent 5-aminosalicylates (5-ASA) releasing preparations (time-dependent 5-ASA) increase 6-thioguanine nucleotide (6-TGN), an active metabolite of thiopurines. However, the effects of pH-dependent 5-ASA releasing preparations (pH-dependent 5-ASA) on thiopurine metabolism were not reported. METHODS: We conducted a retrospective study of 134 IBD patients who received thiopurine treatment. The 6-methylmercaptopurine (6-MMP)/6-TGN values after taking the same dose of thiopurine preparations for at least 28 days were included. RESULTS: There was a significant decrease in the 6-MMP/6-TGN ratio in time-dependent 5-ASA compared with group without 5-ASA preparations and the pH-dependent 5-ASA group (p = 0.008 and < 0.001 respectively). Spearman's rank correlation coefficient indicated a negative relationship between the daily oral dose of time-dependent 5-ASA and the 6-MMP/6-TGN ratio (r = -0.362, p = 0.003). Multivariate logistic regression analysis was performed in the groups with 6-MMP/6-TGN ratios of 1 or more and less than 1. The use of time-dependent 5-ASA and concomitant allopurinol negatively affected the independent 6-MMP/6-TGN ratio (p = 0.006 and 0.007 respectively). CONCLUSION: Our study revealed that time-dependent but not pH-dependent 5-ASA decreases the 6-MMP/6-TGN ratio. We also confirmed that concomitant allopurinol results in a low 6-MMP/6TGN ratio.

Structural optimization and additional targets identification of antisense oligonucleotide G3139 encapsulated in a neutral cytidinyl-lipid combined with a cationic lipid in vitro and in vivo.

Antisense oligonucleotides (ASOs) usually contain a fully phosphorothioate (PS) backbone, which possibly interact with many genes and proteins under intracellular conditions. G3139 is an ASO that targets Bcl-2 mRNA and induces cell apoptosis. Here, we report a kind of cytidinyl-lipid combined with a cationic lipid (DNCA/CLD, molar ration, 28:3, named mix), which may interact with oligonucleotides via H-bond formation, pi-stacking and electrostatic interaction, accompanied by low zeta potentials. The IC50 value of G3139 delivered by mix-lipid reduced from above 20 µM to 0.158 µM for MCF-7/ADR, and exhibited stronger antiproliferation upon other cancer cell lines. In addition, PS modification in the 3'-half of G3139 (especially at positions 13-16) enhanced serum stability, target specificity and anticancer activity. Also, a locked nucleic acid (LNA) gapmer G3139 (LNA-G3139) showed superior antiproliferation (78.5%) and Bcl-2 mRNA suppression effects (85.5%) at 200 nM, mainly due to its high complementary RNA affinity. More apoptosis-associated targets were identified, and a lower level of non-specific protein binding (HSA) revealed that both antisense and aptamer mechanisms might simultaneously exist. A combination of a new delivery system and chemical modifications, such as in LNA-G3139, may have potential clinical application prospects in the future.

A population pharmacokinetic meta-analysis of custirsen, an antisense oligonucleotide, in oncology patients and healthy subjects.

AIMS: Custirsen (OGX-011/TV-1011), a second-generation antisense oligonucleotide that reduces clusterin production, is under investigation with chemotherapy in prostate and lung cancer. This meta-analysis evaluated the population pharmacokinetics (PK) of custirsen in cancer patients and healthy subjects. METHODS: The population PK analysis used custirsen plasma concentrations from five Phase 1 studies, one Phase 1/2 study, and one Phase 3 study in two stages. Cancer patients received multiple doses of custirsen (40-640 mg intravenously over 120 min) with chemotherapy; healthy subjects received single or multiple doses (320-640 mg). An interim population PK model was developed using a nonlinear mixed-effect approach incorporating data from four Phase 1 or 1/2 studies, followed by model refinement and inclusion of two Phase 1 and one Phase 3 studies. RESULTS: The final model was developed with 5588 concentrations from 631 subjects with doses of 160-640 mg. Custirsen PK was adequately described by a three-compartment model with first-order elimination. For a representative 66-year-old individual with body weight 82 kg and serum creatinine level 0.933 mg dl-1 , the estimated typical (95% CI) parameter values were clearance (CL) = 2.36 (2.30-2.42) l h-1 , central volume of distribution (V1 ) = 6.08 (5.93-6.23) l, peripheral volume of distribution (V2 ) = 1.13 (1.01-1.25) l, volume of the second peripheral compartment (V3 ) = 15.8 (14.6-17.0) l, inter-compartmental clearance Q2 = 0.0755 (0.0689-0.0821) l h-1 , and Q3 = 0.0573 (0.0532-0.0614) l h-1 . Age, weight and serum creatinine were predictors of CL; age was a predictor of Q3 . CONCLUSION: A population PK model for custirsen was successfully developed in cancer patients and healthy subjects, including covariates contributing to variability in custirsen PK.

Impact of dosing regimen of custirsen, an antisense oligonucleotide, on safety, tolerability and cardiac repolarization in healthy subjects.

AIMS: Custirsen (OGX-011/TV-1011), a second-generation antisense oligonucleotide (ASO) that reduces clusterin production, is under investigation with chemotherapy in patients with solid tumours. Custirsen is associated with constitutional symptoms (CS) that may interfere with clinical pharmacology investigations, such as QT interval studies. Experience with other ASOs suggests NSAID premedication may ameliorate CS, but we observed suboptimal outcomes in healthy subjects given custirsen and NSAIDs. We sought to establish a custirsen regimen for future clinical pharmacology studies in healthy subjects. METHODS: Subjects received custirsen (640 mg intravenously over 120 min) with dexamethasone premedication or increasing doses (320, 480, 640 mg over 6 days) of custirsen with dexamethasone premedication, then one full custirsen dose without premedication on day 8. Incidence/severity of adverse events (AEs) and extensive electrocardiogram readings were evaluated. Pharmacokinetic parameters were estimated. RESULTS: AEs included CS, elevated transaminases and prolonged activated partial thromboplastin time (aPTT) that were predominantly grade 1/2. Administration of increasing custirsen doses and dexamethasone premedication reduced the incidence of CS associated with full dose custirsen. Transaminase elevation showed a dose-dependent effect (0% at days 2, 4, 27% at day 6) with the highest custirsen doses. Increasing doses of custirsen may have mitigated the severity but not incidence of aPTT prolongation. Neither regimen was associated with cardiac repolarization changes in QT values or concentration-effect analyses. The custirsen pharmacokinetic profile was consistent with previous experience. CONCLUSION: Escalation of custirsen dose combined with dexamethasone premedication reduced CS associated with full dose custirsen and should be considered in future clinical pharmacology studies of custirsen.

Targeted nanoparticle delivery overcomes off-target immunostimulatory effects of oligonucleotides and improves therapeutic efficacy in chronic lymphocytic leukemia.

Several RNA-targeted therapeutics, including antisense oligonucleotides (ONs), small interfering RNAs, and miRNAs, constitute immunostimulatory CpG motifs as an integral part of their design. The limited success with free antisense ONs in hematologic malignancies in recent clinical trials has been attributed to the CpG motif-mediated, TLR-induced prosurvival effects and inefficient target modulation in desired cells. In an attempt to diminish their off-target prosurvival and proinflammatory effects and specific delivery, as a proof of principle, in the present study, we developed an Ab-targeted liposomal delivery strategy using a clinically relevant CD20 Ab (rituximab)-conjugated lipopolyplex nanoparticle (RIT-INP)- and Bcl-2-targeted antisense G3139 as archetypical antisense therapeutics. The adverse immunostimulatory responses were abrogated by selective B cell-targeted delivery and early endosomal compartmentalization of G3139-encapsulated RIT-INPs, resulting in reduced NF-κB activation, robust Bcl-2 down-regulation, and enhanced sensitivity to fludarabine-induced cytotoxicity. Furthermore, significant in vivo therapeutic efficacy was noted after RIT-INP-G3139 administration in a disseminated xenograft leukemia model. The results of the present study demonstrate that CD20-targeted delivery overcomes the immunostimulatory properties of CpG-containing ON therapeutics and improves efficient gene silencing and in vivo therapeutic efficacy for B-cell malignancies. The broader implications of similar approaches in overcoming immunostimulatory properties of RNA-directed therapeutics in hematologic malignancies are also discussed.

Custirsen (OGX-011): a second-generation antisense inhibitor of clusterin in development for the treatment of prostate cancer.

Clusterin is a stress-induced cytoprotective chaperone that confers broad-spectrum treatment resistance and is overexpressed across a number of cancers. custirsen (OGX-011) is a promising novel second-generation antisense inhibitor of clusterin in clinical development. This article describes the mechanism of action and safety profile of OGX-011 and details the Phase I and II results in human solid organ malignancies. Two Phase III registration trials are currently under recruitment evaluating OGX-011 in combination with chemotherapy in patients with metastatic castration-resistant prostate cancer. These studies not only have the potential to significantly alter the standard of care in prostate cancer, but would also endorse a new class of targets and targeted therapy approach for cancer.

In vitro and in vivo activity of 4-thio-uridylate against JY cells, a model for human acute lymphoid leukemia.

We have previously reported the in vitro anti-proliferative effect of 4-thio-uridylate (s(4)UMP) on OCM-1 uveal melanoma cells. Here, we assessed the efficacy of s(4)UMP on JY cells. Treatment of JY cells with s(4)UMP suppressed their colony forming activity and induced apoptosis; healthy human bone marrow granulocyte-macrophage progenitor cells were 14-fold less sensitive to the nucleotide. In vivo effectiveness of s(4)UMP was determined using xenograft SCID mouse model. s(4)UMP decreased the cell number and colony forming activity of the total cell content of the femur of SCID mice transplanted with JY cells without affecting the bone marrow of healthy mice. These results suggest that s(4)UMP alone or in combination with other clinically approved anti-leukemic remedies should be further explored as a potential novel therapeutic agent.

Pharmacokinetic evaluation of oblimersen sodium for the treatment of chronic lymphocytic leukemia.

INTRODUCTION: Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in the western hemisphere. Developing new therapies remains a priority as present treatment options do not offer a cure. BCL-2 overexpression in CLL is associated with aggressive disease features and resists chemotherapy. Oblimersen sodium (G3139) is a phosphorothioate oligonucleotide antisense drug targeting the BCL-2 mRNA and is the first antisense to reach advanced clinical testing in oncology. Preclinical evaluation has demonstrated good antineoplastic effect in B-cell cancers; several clinical trials have confirmed its safety and efficacy both alone and in combination with other therapeutics. AREAS COVERED: This review focuses on the chemistry, pharmacodynamics, pharmacokinetics and clinical evaluation of oblimersen in CLL. PubMed and MEDLINE searches assisted in data collection. EXPERT OPINION: Bcl-2 is an important target in CLL. Antisense therapy is a novel approach to target oncoproteins; this can be beneficial in the clinical setting. Oblimersen sodium demonstrates the clinical safety of the antisense therapeutic approach and, with chemotherapy, shows survival advantage in a subset of CLL patients. However, future approval of oblimersen sodium in CLL remains uncertain. Nevertheless, BCL-2 remains a critical target in drug development and is an area of high-priority research.

Phase I trial of oblimersen (Genasense®) and gemcitabine in refractory and advanced malignancies.

BACKGROUND: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Inhibition of BCL-2 in small cell lung cancer cell lines with oblimersen, an antisense BCL-2 oligodeoxynucleotide (ODN): in vitro and in vivo enhancement of radiation response.

BACKGROUND: Oblimersen, an ODN targeting BCL-2 RNA, has been shown to be effective in reducing BCL-2 expression in vitro and in in vivo models engineered to overexpress BCL-2. The present study evaluated the efficacy of combining BCL-2 ODN and radiation in small-cell lung cancers (SCLC) cell lines. MATERIALS AND METHODS: The in vitro effect was determined using short term (cell viability) and long term (clonogenic) assays. Apoptosis, BCL-2 expression and intratumoural uptake of the FAM-ODN with or without prior radiation treatment were also evaluated. Combination of ODN and RT was also assessed in vivo. RESULTS: Radiation was shown to increase intracellular and intratumoural penetration of oblimersen, confirming previous results obtained in prostate cancer xenograft models. Oblimersen decreased BCL-2 protein expression in vitro and in vivo. BCL-2 ODN sensitised H69 cells to radiation in vitro and in vivo. Oblimersen increased radiation-induced apoptosis and decreased in vivo tumoural vascularisation. CONCLUSION: Oblimersen was shown to increase in vitro and in vivo effect of RT on SCLC cell lines. Radiation increases intracellular and intratumoural penetration of ODN. This pre-clinical study argues in favour of clinical development in localised SCLC.

Phase I study of the c-raf-1 antisense oligonucleotide ISIS 5132 in combination with carboplatin and paclitaxel in patients with previously untreated, advanced non-small cell lung cancer.

BACKGROUND: A phase I trial was performed to evaluate the administration of carboplatin/paclitaxel in combination with ISIS-5132, a phosphorothioate antisense oligodeoxynucleotide inhibitor of c-raf-1 kinase expression, in patients with advanced non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: Previously untreated patients with stage IIIB/IV NSCLC received ISIS 5132 by continuous intravenous infusion at 2.0 mg/kg/d for 14 days. Starting doses were paclitaxel 175 mg/m(2) and carboplatin targeting an area under the free platinum plasma concentration-time curve (AUC(fp)) of 5 mg . min/ml (dose level 1). The carboplatin dose was then increased to AUC(fp) 6 mg . min/ml (dose level 2) after which the paclitaxel dose was increased to 200 mg/m(2) (dose level 3). The maximum tolerated dose was established by toxicity during the first two 21-day cycles of therapy. The pharmacokinetics of all three agents was determined before and during the ISIS 5132 infusion. RESULTS: Thirteen patients were treated with the carboplatin/paclitaxel/ISIS 5132 combination. Dose-limiting neutropenia occurred in two patients at dose level 3. Grade 3 and 4 nonhematologic toxicities were infrequent and limited to nausea and constipation. The maximum tolerated doses were carboplatin AUC(fp) 6 mg . min/ml, paclitaxel 175 mg/m(2), and ISIS 5132 2.0 mg/kg/d for 14 days. There were no objective responses and the concurrent infusion of ISIS 5132 did not alter the plasma pharmacokinetics of paclitaxel or total platinum. CONCLUSION: ISIS 5132 can be safely combined with standard doses of carboplatin and paclitaxel. Combining cytotoxic chemotherapeutic agents with inhibitors of aberrant signal transduction mediated by Raf proteins produced no objective responses in the dose and schedule administered in this study.

Trabedersen, a TGFbeta2-specific antisense oligonucleotide for the treatment of malignant gliomas and other tumors overexpressing TGFbeta2.

Trabedersen (AP-12009), which is being developed by Antisense Pharma GmbH, is a synthetic antisense oligodeoxynucleotide designed to block the production of TGFbeta2, a secreted protein that can exert protumor effects. Trabedersen is indicated for the treatment of malignant brain tumors and other solid tumors overexpressing TGFbeta2, such as those of the skin, pancreas and colon. Preclinical studies demonstrated that trabedersen reduced the secretion of TGFbeta2 in cultured tumor cells and exhibited antitumor activity ex vivo. It was also demonstrated that chronic intracerebral or intravascular administration of trabedersen did not cause life-threatening side effects in animals. This observation was confirmed in early clinical trials in patients with advanced cancer. In a phase IIb trial, improved survival was observed in patients with brain tumors who were intratumorally administered trabedersen, compared with patients receiving standard chemotherapy. However, this observation requires validation by an ongoing large-scale, phase III, randomized, controlled trial. Meanwhile, continued research on trabedersen should help to determine the roles of TGFbeta2 in cancer and also further the development of antisense technology.

Phase I study of MG98, an oligonucleotide antisense inhibitor of human DNA methyltransferase 1, given as a 7-day infusion in patients with advanced solid tumors.

PURPOSE: To assess the safety and tolerability, pharmacokinetics, and early evidence of antitumor activity of escalating doses of MG98, an antisense oligonucleotide to DNA methyltransferase 1 (DNMT1), which has been shown to reduce CpG island methylation and allow reexpression of tumor suppressor genes in vitro. EXPERIMENTAL DESIGN: In this phase I, open-label study, patients with advanced solid malignancies were treated with escalating doses of MG98 administered as a continuous i.v. infusion over 7 days repeated every 14 days. Cohorts of three patients, which could be expanded to six patients, were studied. The maximum tolerated dose was defined as the highest dose at which no more than 33% of subjects experienced dose-limiting toxicity. Pharmacokinetic and pharmacodynamic parameters of MG98 were also characterized. RESULTS: Thirty-three patients were treated at doses of 100 to 250 mg/m(2)/d MG98. MG98 was well tolerated with mild fatigue and myalgia, dose-limiting toxicity was asymptomatic transaminitis, and the maximum tolerated dose was 200 mg/m(2)/d. One patient achieved a partial response and another prolonged disease stabilization. Plasma half-life of MG98 was short (2 hours), drug concentrations reaching a dose-dependent steady state during infusion with a volume of distribution equivalent to plasma volume. Suppression of DNMT1 expression was observed in 26 of 32 patients studied. CONCLUSIONS: MG98 was well tolerated with early evidence of clinical activity. Proof of mechanism was observed and measurement of DNMT1 expression in peripheral blood mononuclear cells may be useful in future phase II development.

Transferrin receptor targeted lipopolyplexes for delivery of antisense oligonucleotide g3139 in a murine k562 xenograft model.

PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Phase I/II study of G3139 (Bcl-2 antisense oligonucleotide) in combination with doxorubicin and docetaxel in breast cancer.

PURPOSE: Preclinical data showed enhancement of breast cancer cell death when G3139 was combined with anthracyclines and taxanes. We evaluated the efficacy and safety of a Bcl-2 antisense oligonucleotide, G3139, in combination with doxorubicin (A) and docetaxel (T) in patients with locally advanced breast cancer (LABC). EXPERIMENTAL DESIGN: Following a brief phase I to determine the phase II dose, patients with locally advanced breast cancer received G3139 administered by continuous i.v. infusion for 5 to 7 days with bolus A (50 mg/m2) and T (75 mg/m2) administered on either day 3 or 6 of therapy with G3139. Cycles were repeated every 21 days x 6 in the neoadjuvant setting. Serial plasma samples were obtained for pharmacokinetic analysis. Tissue samples were obtained before and after therapy for pharmacodynamic analysis of Bcl-2 expression. RESULTS: Thirty patients (median age, 49 years; range, 24-71 years) received 160 cycles. During the phase I portion of the trial, the dose of G3139 was escalated from 3 to 7 mg/kg/d (i.v. for 5 days) in combination with AT. During the phase II portion of the trial, several doses and schedules of G3139 were evaluated. There were no pathologic complete responses. Pharmacodynamic studies showed limited Bcl-2 down-regulation in the primary tumors. CONCLUSIONS: G3139 in combination with doxorubicin and docetaxel is well tolerated. No pathologic complete response was seen and pharmacodynamic studies showed very little down-regulation of Bcl-2 in primary tumors, perhaps related to issues with insufficient drug delivery to the intact tumor.

A phase I pharmacokinetic and pharmacodynamic correlative study of the antisense Bcl-2 oligonucleotide g3139, in combination with carboplatin and paclitaxel, in patients with advanced solid tumors.

PURPOSE: 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. EXPERIMENTAL DESIGN: 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. RESULTS: 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. CONCLUSIONS: 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.

Oblimersen combined with docetaxel, adriamycin and cyclophosphamide as neo-adjuvant systemic treatment in primary breast cancer: final results of a multicentric phase I study.

BACKGROUND: Combining the Bcl-2 down-regulator oblimersen with cytotoxic treatment leads to synergistic antitumor effects in preclinical trials. This multicentric phase I study was carried out to evaluate maximum tolerated dose (MTD), safety and preliminary efficacy of oblimersen in combination with docetaxel, adriamycin and cyclophosphamide as neo-adjuvant systemic treatment (NST) in primary breast cancer (PBC). METHODS: Previously untreated patients with PBC T2-4a-c N0-3 M0 received one cycle of docetaxel 75 mg/m(2), adriamycin 50 mg/m(2) and cyclophosphamide 500 mg/m(2) administered on day 5 combined with escalating doses of oblimersen as a 24-h continuous infusion on days 1-7 followed by five cycles of combination of docetaxel, adriamycin and cyclophosphamide (TAC) without oblimersen every 3 weeks. Prophylactic antibiotic therapy and granulocyte colony-stimulating factor administration were used in all six cycles. Blood serum samples were taken throughout the treatment period for pharmacokinetic analysis. RESULTS: Twenty-eight patients were enrolled (median age, 50 years; ductal-invasive histology, 68%; tumorsize 2-5 cm, 61%; grade 3, 43%; hormone receptor negative, 36%; Her2 positive 18%) and received oblimersen in a dose of 3 mg/kg/day (cohort I, nine patients), 5 mg/kg/day (cohort II, nine patients) and 7 mg/kg/day (cohort III, 10 patients) respectively. No dose-limiting toxicity occurred. Following oblimersen combined with TAC, the most severe toxicity was neutropenia [National Cancer Institute-Common Toxicity Criteria (NCI-CTC) grades 1-2/3/4] which developed in 0/0/56% of patients (cohort I), 11/0/56% of patients (cohort II) and 20/20/50% of patients (cohort III). No febrile neutropenia occurred. Most common adverse events (all NCI-CTC grade < or = 2) were fatigue, nausea, alopecia, headache and flue-like symptoms observed in 78% (cohort I), 89% (cohort II) and 90% (cohort III) of patients. With increasing dose of oblimersen, a higher incidence of grade IV leukopenia and neutropenia was noted. At the MTD of 7 mg/kg/day of oblimersen, serious adverse events occurred in 40% of the patients. CONCLUSION: Oblimersen up to a dose of 7 mg/kg/day administered as a 24-h infusion on days 1-7 can be safely administered in combination with standard TAC on day 5 as NST in patients with PBC. The safety and preliminary efficacy warrants further evaluation of oblimersen in combination with every cycle of the TAC regimen in a randomized trial.