Repetitive high-dose topotecan, carboplatin, and paclitaxel with peripheral blood progenitor cell support in previously untreated ovarian cancer: results of a Phase I study

Post-operative sequential high-dose chemotherapy with haematopoietic stem cell support as front-line treatment in advanced ovarian cancer: a phase II multicentre study

In spite of multimodal management including aggressive surgery and chemotherapy, the prognosis of advanced ovarian cancer (AOC) remains poor. Multicycle high-dose chemotherapy (HDC) with haematopoietic stem cell (HSC) support has been shown to be a promising procedure in various cancers including AOC. We conducted a phase II multicentre study to evaluate feasibility, toxicity and efficacy of post-operative front-line sequential HDC with HSC support in AOC. Thirty four patients with stage IIIC/IV received a post-operative sequential combination of high-dose cyclophosphamide/epirubicin (D1, D21) with HSC harvesting, high-dose carboplatin (D42, D98) followed by HSC infusion, and dose-dense paclitaxel (D63, D77, D119, D133). Rh-G-CSF (filgrastim) was administered following all cycles. Primary endpoint was pathological complete response rate (pCR). Thirty patients received at least 7 of the scheduled 8 cycles. Haematological toxicity was significant but manageable. Grade 3/4 extra-haematopoietic toxicities were relatively uncommon and reversible. No toxicity-related death was observed. The observed pCR was 37% and did not reach the initial endpoint. Post-operative front-line sequential HDC in AOC is feasible and safe in a multicentre setting. The observed pCR does not support a clear advantage over conventional treatment. This approach remains an experimental strategy to further optimise and validate.

Toxicity of the topoisomerase I inhibitors

The topoisomerase I inhibitors represent a class of antineoplastic agents with a wide spectrum of activity against malignancies. Currently available topo-isomerase I inhibitors are derivatives of the parent compound, camptothecin. Irinotecan is most active against gastrointestinal (GI) tumours, and has predominantly GI and haematological toxicities. Significant pharmacokinetic variability occurs in patients with hepatic dysfunction, particularly those with glucuronidation pathway deficiencies. The toxicity of topotecan is principally haematological with little extramedullary toxicity. Topotecan is well-tolerated in patients with significant hepatic dysfunction; however, patients with even mild renal insufficiency require significant dose reductions. This article discusses the toxicities of these drugs in detail, including the need for dose adjustments in selected patient populations.

Randomized Phase II trial of two high-dose chemotherapy regimens with stem cell transplantation for the treatment of advanced ovarian cancer in first remission or chemosensitive relapse: a Southwest Oncology Group study

OBJECTIVES

To evaluate response rates, progression-free survival (PFS), overall survival (OS), and toxicity of two high-dose chemotherapy regimens with stem cell rescue used to treat patients with recurrent or persistent stage III/IV ovarian cancer, with the goal of taking one forward into a Phase III comparison with conventional therapy.

METHODS

Patients under 65 with clinically or pathologically persistent disease after initial chemotherapy or those relapsing >6 months after a complete remission (CR) were randomized to CMC carboplatin (1500 mg/m(2)), mitoxantrone (75 mg/m(2)), and cyclophosphamide (120 mg/kg)], or CTC: [cisplatin (165 mg/m(2)), thiotepa (600 mg/m(2)), and cyclophosphamide (5625 mg/m(2))] with stem cell rescue.

RESULTS

Of 67 randomized, the 32 and 26 eligible in the CMC and CTC arms were matched including age (median 49), maximum tumor diameter, and disease status at transplant. Low-risk disease (maximum diameter disease <or= 0.5 cm and platinum sensitivity) was demonstrated in only approximately one-half of the patients. There were two treatment-related deaths in each arm. The median PFS was 13 and 8 months, respectively, for the CMC and CTC arms. The median OS was 29 and 22 months for the CMC and CTC arms. In a multivariate analysis of PFS, normal CA125 at transplant and CR to primary therapy were significant; for OS, normal CA125 and platinum sensitivity were significant.

CONCLUSIONS

The CMC regimen was the superior regimen. However, few patients were long-term progression-free survivors. A clinical CR to primary therapy and a normal CA125, seen in a minority of patients, were requirements for a favorable outcome.

Thawing of cryopreserved mobilized peripheral blood--comparison between waterbath and dry warming device

BACKGROUND

Thawing of cryopreserved mobilized peripheral blood (MPB) is routinely performed for autologous and allogeneic MPB transplantation. Usually thawing is achieved by submerging the cell bag in a waterbath (37 degrees C temperature). We compared the effectiveness of thawing cryopreserved MPB in a waterbath with an electric dry-warming device containing warmed gel pads (Sahara, Transmed).

METHODS

Two cryopreserved bags from each of 31 apheresis procedures were thawed in a waterbath and under dry conditions in parallel. Viability (dye exclusion), apoptosis/necrosis (annexin/propidiumiodide staining) and clonogenic potential (CFU-E plus BFU-E, CFU-GM) of the cells were tested after thawing.

RESULTS

Statistical analysis by Wilcoxon matched-pair test showed no significant difference between the thawing procedures in terms of the in vitro parameters tested.

DISCUSSION

Our results indicate that thawing of cryopreserved MPB using dry warming and water bath give similar viability, apoptosis/necrosis rate and clonogenic potential. Both procedures take about the same amount of time and are easy to perform. Nevertheless, the potentially decreased risk of bacterial contamination of either the cell product or the patient room, and guidelines of good clinical practice (GCP), favor the use of the dry warming procedure.

Topoisomerase I interactive agents

Increased insight into the mechanism of interaction of topoisomerase I interactive agents will maximize the therapeutic index and enhance the development of additional agents. Preclinical studies designed to elucidate mechanisms by which the topoisomerase I interactive agents induce cell death will be essential. The role of ABC transporters in resistance to topoisomerase I interactive agents has been recently appreciated and future studies should be directed at circumventing this resistance. The results of preclinical studies must be translated into the design of clinical trials so that these agents can be used rationally. In this regard results of preclinical studies have clearly pointed to the enhanced antitumor activity from protracted dosing of topoisomerase I interactive agents and results of clinical trials are now supporting these preclinical findings. Finally, investigators are trying to understand better the mechanism(s) of the dose-limiting toxicities observed with the currently available topoisomerase I interactive agents in an effort to enable the optimal dosing of these agents. Even though the first priority must be to determine the therapeutic potential of the currently available agents, it is reassuring to know that other topoisomerase I interactive agents are currently under development.

Reversal of P-glycoprotein-mediated paclitaxel resistance by new synthetic isoprenoids in human bladder cancer cell line

We isolated a paclitaxel-resistant cell line (KK47/TX30) from a human bladder cancer cell line (KK47/WT) in order to investigate the mechanism of and reversal agents for paclitaxel resistance. KK47/TX30 cells exhibited 700-fold resistance to paclitaxel and cross-resistance to vinca alkaloids and topoisomerase II inhibitors. Tubulin polymerization assay showed no significant difference in the ratio of polymerized alpha- and beta-tubulin between KK47/WT and KK47/TX30 cells. Western blot analysis demonstrated overexpression of P-glycoprotein (P-gp) and lung resistance-related protein (LRP) in KK47/TX30 cells. Drug accumulation and efflux studies showed that the decreased paclitaxel accumulation in KK47/TX30 cells was due to enhanced paclitaxel efflux. Cell survival assay revealed that verapamil and cepharanthine, conventional P-gp modulators, could completely overcome paclitaxel resistance. To investigate whether new synthetic isoprenoids could overcome paclitaxel resistance, we synthesized 31 isoprenoids based on the structure of N-solanesyl-N,N'-bis(3,4-dimethoxybenzyl)ethylenediamine (SDB), which could reverse multidrug resistance (MDR), as shown previously. Among those examined, trans-N,N'-bis(3,4-dimethoxybenzyl)-N-solanesyl-1,2-diaminocyclohexane (N-5228) could completely reverse paclitaxel resistance in KK47/TX30 cells. N-5228 inhibited photoaffinity labeling of P-gp by [(3)H]azidopine, suggesting that N-5228 could bind to P-gp directly and could be a substrate of P-gp. Next, we investigated structural features of these 31 isoprenoids in order to determine the structural requirements for the reversal of P-gp-mediated paclitaxel resistance, suggesting that the following structural features are important for overcoming paclitaxel resistance: (1) a basic structure of 8 to 10 isoprene units, (2) a cyclohexane ring or benzene ring within the framework, (3) two cationic sites in close proximity to each other, and (4) a benzyl group with 3,4-dimethoxy functionalities, which have moderate electron-donating ability. These findings may provide valuable information for the development of P-gp-mediated MDR-reversing agents.