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.

Pegylated liposomal doxorubicin and gemcitabine in a fixed dose rate infusion for the treatment of patients with poor prognosis of recurrent ovarian cancer: a phase Ib study.

INTRODUCTION: Pegylated liposomal doxorubicin (PLD) is currently the reference treatment for platinum-resistant ovarian cancer. The combination of PLD and gemcitabine and the administration of gemcitabine at a fixed dose rate infusion (FDRI) seem to have additive activity in this disease setting. We have launched a phase Ib study with the combination of FDRI gemcitabine followed by PLD in recurrent ovarian cancer with a platinum-free interval of less than 1 year, with parallel pharmacokinetic and pharmacogenetic studies. METHODS: The starting dose of gemcitabine was 1500 mg/m², 10 mg/m² per minute, every 2 weeks (± 250 mg gemcitabine titration depending on toxicity), followed by PLD 35 mg/m² every 4 weeks. Gemcitabine pharmacokinetics and equilibrative nucleoside transporter 1, deoxycytidine kinase, and ribonucleotide reductase M1 gene expression levels were studied. RESULTS: Thirty-five patients were treated at 3 different dose levels (DL). Dose level 1 was not tolerated. Nonfrail patients continued to be treated at DL-1 (G 1250 mg/m² on day 1 and PLD 35 mg/m² on days 1 and 15). Of 10 evaluable nonfrail patients, 4 displayed dose-limiting toxicity. Frail patients were treated at DL-2 (G 1250 mg/m on day 1 and PLD 35 mg/m² on days 1 and 15). Of the 12 evaluable frail patients, 3 developed dose-limiting toxicity. Neutropenia, palmar-plantar erythrodysesthesia and stomatitis were the most common toxicities. The response rate was 42.8% (95% confidence interval [CI], 34.5%-51.1%), with 17.1% (6/35) complete responses and 25.7% (9/35) partial responses. The median progression-free survival was 7.7 months (95% CI, 2.2-13.1). The median overall survival was 13.9 months (95% CI, 9.4-18.4). The administration of PLD after gemcitabine did not influence gemcitabine pharmacokinetics or its metabolites. The addition of PLD to gemcitabine caused a larger and longer induction of the ribonucleotide reductase M1 gene. Patients with higher baseline levels of deoxycytidine kinase had longer progression-free survival. CONCLUSION: The recommended dose for a phase II study of patients with recurrent ovarian cancer having poor prognosis is PLD, 35 mg/m² on day 1, and gemcitabine, 1000 mg/m² on days 1 and 15 delivered at an FDRI of 10 mg/m per minute in 28-day cycles.

Protein kinase C theta is highly expressed in gastrointestinal stromal tumors but not in other mesenchymal neoplasias.

PURPOSE: Gastrointestinal stromal tumors (GIST) are a distinctive group of mesenchymal neoplasms of the gastrointestinal tract. The oncogene KIT has a central role in the pathogenesis of GIST, with c-kit receptor tyrosine kinase (KIT) protein expression being the gold standard in its diagnosis. The identification of GIST patients has become crucial, because the tyrosine kinase inhibitor Imatinib is effective in the treatment of this malignancy. However, a small set of GISTs remain unrecognized, because KIT protein expression is not always evident. The aim of this study was the identification of new markers for the differential diagnosis of GIST. EXPERIMENTAL DESIGN: By analyzing publicly available data from transcriptional profiling of sarcomas, we found that protein kinase C theta (PKC-theta), a novel PKC isotype involved in T-cell activation, is highly and specifically expressed in GIST. PKC-theta expression in GIST was confirmed by reverse transcription-PCR and Western blot. PKC-theta was analyzed by immunohistochemistry in a panel of 26 GIST, 12 non-GIST soft-tissue sarcomas, and 35 tumors from other histologies. RESULTS: We found that all of the GISTs expressed PKC-theta, whereas this protein was undetectable in other mesenchymal or epithelial tumors, including non-GIST KIT-positive tumors. PKC-theta immunoreactivity was also observed in interstitial cells of Cajal. CONCLUSIONS: Our results show that PKC-theta is easily detected by immunohistochemistry in GIST specimens and that it could be a sensitive and specific marker for the diagnosis of this malignancy.

Phase I clinical trial of fixed-dose rate infusional gemcitabine and dacarbazine in the treatment of advanced soft tissue sarcoma, with assessment of gemcitabine triphosphate accumulation.

BACKGROUND: In the current study, the authors set out to determine the dose-limiting toxicity (DLT) and maximum tolerated dose (MTD) associated with a combination of gemcitabine and dacarbazine (DTIC) in patients with advanced soft tissue sarcoma (ASTS), to obtain preliminary information on the activity of this combination, and to explore possible pharmacodynamic interactions between gemcitabine and DTIC. METHODS: Every 2 weeks, 22 patients with refractory ASTS received fixed-dose rate gemcitabine (10 mg/m2/min) at escalating doses, which ranged from 800 mg/m2 to 2160 mg/m2, plus 500 mg/m2 DTIC. Plasma concentrations of gemcitabine and 2',2'-difluorodeoxyuridine, along with gemcitabine triphosphate (dFdCTP) levels in peripheral blood mononuclear cells (PBMCs), were evaluated during the course of treatment. RESULTS: Grade 3 elevation of transaminase and gamma-glutamyltransferase levels represented the DLT associated with the administration of 2160 mg/m2 gemcitabine plus 500 mg/m2 DTIC. This side effect was reversible, rather than cumulative, and did not exceed Grade 3 in its severity. The doses recommended for use in subsequent Phase II studies are 1800 mg/m2 gemcitabine (administered over the course of 3 hours) and 500 mg/m2 DTIC. Hematologic toxicity was moderate, and nonhematologic side effects that did not exceed Grade 2 in severity included the following: asthenia (75% of patients), fever (59%), nausea (52%), stomatitis (48%), anorexia (44%), emesis (40%), flulike syndrome (37%), and erythematous rash (26%). Alopecia was common. Intracellular dFdCTP levels, which were evaluated in 6 patients, reached a mean maximum value of 209 pmol per 10(6) cells (standard deviation, 59 pmol per 10(6) cells) at the conclusion of gemcitabine administration. DTIC had a limited effect on the elimination of dFdCTP from PBMCs. Objective responses were observed in 5 of the 19 patients who were evaluable for treatment efficacy. CONCLUSIONS: The combination of gemcitabine and DTIC possesses an acceptable toxicity profile and may warrant further investigation in patients with ASTS.