Schedule-dependent and -independent antitumor activity of paclitaxel-based combination chemotherapy against M-109 murine lung carcinoma in vivo

Pharmacokinetics of inhaled nanotherapeutics for pulmonary delivery

Pulmonary delivery of lipid-based nanotherapeutics by inhalation presents an advantageous alternative to oral and intravenous routes of administration that avoids enzymatic degradation in gastrointestinal tract and hepatic first pass metabolism and also limits off-target adverse side effects upon heathy tissues. For lung-related indications, inhalation provides localized delivery in order to enhance therapeutic efficacy at the site of action. Optimization of physicochemical properties, selected drug and inhalation format can greatly influence the pharmacokinetic behavior of inhaled nanoparticle systems and their payloads. The present review analyzes a wide range of nanoparticle systems, their formulations and consequent effect on pharmacokinetic distribution of delivered active components after inhalation.

The HB22.7 Anti-CD22 monoclonal antibody enhances bortezomib-mediated lymphomacidal activity in a sequence dependent manner

Most non-Hodgkin's lymphomas (NHL) initially respond to chemotherapy, but relapse is common and treatment is often limited by chemotherapy-related toxicity. Bortezomib, is a highly selective proteasome inhibitor with anti-NHL activity; it is currently FDA approved for second-line treatment of mantle cell lymphoma (MCL). Bortezomib exerts its activity in part through the generation of reactive oxygen species (ROS) and also by the induction of apoptosis.We previously validated CD22 as a potential target in treating NHL and have shown that the anti-CD22 ligand blocking antibody, HB22.7, has significant independent lymphomacidal properties in NHL xenograft models. We sought to determine whether or not these agents would work synergistically to enhance cytotoxicity. Our results indicate that treatment of NHL cell lines with HB22.7 six hours prior to bortezomib significantly diminished cell viability. These effects were not seen when the agents were administered alone or when bortezomib was administered prior to HB22.7. Additionally, HB22.7 treatment prior to bortezomib increased apoptosis in part through enhanced ROS generation. Finally, in a mouse xenograft model, administration of HB22.7 followed 24 hours later by bortezomib resulted in 23% smaller tumor volumes and 20% enhanced survival compared to treatment with the reverse sequence. Despite the increased efficacy of HB22.7 treatment followed by bortezomib, there was no corresponding decrease in peripheral blood cell counts, indicating no increase in toxicity. Our results suggest that pre-treatment with HB22.7 increases bortezomib cytotoxicity, in part through increased reactive oxygen species and apoptosis, and that this sequential treatment combination has robust efficacy in vivo.

Paclitaxel-carboplatin combination chemotherapy in advanced breast cancer: accumulating evidence for synergy, efficacy, and safety

Patients with metastatic breast cancer receive multiple lines of cytotoxic chemotherapy, with taxane and anthracycline-based regimens being the most active. Anthracyclines carry the risk of significant cardiotoxicity at high cumulative doses and when combined with trastuzumab, an anti-HER2 antibody. Carboplatin has shown promising single-agent activity in advanced breast cancer, is not a P-glycoprotein substrate, and is conveniently administered on an outpatient basis. Preclinical experiments demonstrated schedule-dependent synergistic cytotoxic effects of the paclitaxel first/carboplatin last (PC) combination. Pharmacokinetic parameters of paclitaxel and carboplatin were studied by Hellenic Cooperative Oncology Group (HECOG) and no significant interaction or correlation with clinical parameters were found. We assessed PC both as salvage as well as first-line treatment of advanced breast cancer patients in phase II studies which disclosed 40-60% response rates and median survival times of 12-20 mo with manageable toxicity. These results were confirmed by other groups and prompted us to the first randomized phase III trial comparing PC to the standard of epirubicin/paclitaxel (EP), a trial that showed equivalent efficacy and tolerable toxicity for PC. Registry retrospective analysis identified factors prognostic for improved outcome: good performance status, low tumor burden, lack of anthracycline exposure and of hormonal maintenance therapy. PC combinations with HER1 or HER2 modulators are being evaluated both by HECOG and by international groups. Paclitaxel coupled with carboplatin provides an alternative therapeutic option for anthracycline-exposed patients and warrants further clinical research in the direction of anthracycline-free management of metastatic breast cancer.

Phase I study of a weekly schedule of fixed-dose paclitaxel and escalating doses of cisplatin for recurrent or unresectable gastric cancer in Japan

The authors objective was to determine the toxicities and maximum tolerated dose of a dose-dense schedule of fixed-dose paclitaxel and escalating doses of cisplatin in patients with recurrent or unresectable carcinoma of the stomach. On days 1, 8, 15, 29, 36, and 43, patients received a fixed dose of paclitaxel (80 mg/m2 over 1 hour after a short premedication) followed by a 30-minute infusion of cisplatin at dose levels of 7, 15, 20, and 25 mg/m2. Six patients were treated at each dose level, except for the dose of 25 mg/m2 cisplatin. All the patients were assessed for toxicity and 17 patients (81%) were evaluated for response. The cisplatin dose could be escalated to 25 mg/m2. At the dose of 80 mg/m2 paclitaxel and 25 mg/m2 cisplatin, all 3 patients developed dose-limiting toxicity of the gastrointestinal tract. There were no treatment-related deaths. Leukopenia grades 3 or 4 was seen in 5 patients (11.1%), but infectious complications were not encountered. Other toxicities were mild and easily managed. Weekly paclitaxel at a dose of 80 mg/m2 infused over 1 hour, followed by an infusion of 20 mg/m2 cisplatin is recommended for further study in patients with recurrent or unresectable gastric cancer.

Sequence-dependent antitumor efficacy of combination chemotherapy with nedaplatin, a newly developed platinum, and paclitaxel

We evaluated the sequence dependency of antitumor efficacy and toxicity in combination therapy of nedaplatin (NDP) with paclitaxel (TXL) against Lewis lung carcinoma. The sequential administration of NDP prior to TXL (NT therapy) resulted in severe body weight loss followed by frequent toxic death of mice. In contrast, the sequential dosing of TXL prior to NDP (TN therapy) resulted in synergistically enhanced inhibition of tumor growth with less toxicity compared with the NT therapy. Comparing the antitumor activity of NDP plus TXL with that of cisplatin (CDDP) plus TXL or carboplatin (CBDCA) plus TXL, the combination effect of NDP plus TXL was significantly higher than that of CDDP plus TXL or CBDCA plus TXL. These results indicate that the TN therapy may have significant potential in clinical use.

Novel combination chemotherapy in the treatment of non-small cell lung cancer

Treatment of patients with advanced non-small cell lung cancer (NSCLC) remains a vexing problem and long-term survival beyond 5 years is extremely rare. Five new agents, paclitaxel, docetaxel, vinorelbine, gemcitabine and irinotecan, have been introduced for the treatment of NSCLC and investigated extensively both preclinically and clinically. Monotherapy with one of these agents has produced survival benefits over the best supportive care in Phase III studies. Combination chemotherapy with a new agent and platinum produced a higher response rate than conventional cisplatin-based chemotherapy and improved survival was observed in some randomised trials. There was little difference in efficacy and toxicity between the chemotherapeutic regimens with a new agent and a platinum in Phase III trials, suggesting the clinical utility of these regimens is similar. Many trials have focused on regimens containing two new agents, with or without platinum. Preliminary results of Phase III trials of three drug combinations versus two drug combinations suggested the former to be more promising, in terms of response rates and survival. Whether the era of platinum-based chemotherapy in the treatment of NSCLC should continue or not must be determined by Phase III trials, evaluating the use of a platinum agent with one of the new agent combinations. These aggressive chemotherapeutic combinations will hopefully improve survival and quality of life for patients with advanced NSCLC.