Phase 2 study of canfosfamide in combination with pegylated liposomal doxorubicin in platinum and paclitaxel refractory or resistant epithelial ovarian cancer

<p>Abstract</p> <p>Background</p> <p>Canfosfamide is a novel glutathione analog activated by glutathione S-transferase P1-1. This study evaluated the safety and efficacy of canfosfamide in combination with pegylated liposomal doxorubicin (PLD) in patients with platinum resistant ovarian cancer. Patients with platinum resistant ovarian carcinoma and measurable disease received canfosfamide at 960 mg/m²in combination with PLD at 50 mg/m², intravenously day 1 in every 28 day cycles until tumor progression or unacceptable toxicities. The primary endpoints were objective response rate (ORR) and progression-free survival (PFS).</p> <p>Results</p> <p>Canfosfamide plus PLD combination therapy was administered at 960/50 mg/m², respectively. Thirty-nine patients received a median number of 4 cycles (range 1.0-18.0). The ORR was 27.8% (95% CI, 14.2-45.2) with a disease stabilization rate of 80.6% (95% CI, 64.0-91.8) in the evaluable population. The CA-125 marker responses correlated with the radiological findings of complete response or partial response. The median PFS was 6.0 months (95% CI, 4.2-7.9) and median survival was 17.8 months. The combination was well tolerated. Myelosuppression was managed with dose reductions and growth factor support. Grade 3 febrile neutropenia was observed in 2 patients (5.1%). Non-hematologic adverse events occurred at the expected frequency and grade for each drug alone, with no unexpected or cumulative toxicities.</p> <p>Conclusions</p> <p>Canfosfamide in combination with PLD is well tolerated and active in platinum and paclitaxel refractory or resistant ovarian cancer. A randomized phase 3 study was conducted based on this supportive phase 2 study.</p> <p>Trial Registration</p> <p>This study was registered at www.clinicaltrials.gov: NCT00052065.</p

A Phase II study of trabectedin single agent in patients with recurrent ovarian cancer previously treated with platinum-based regimens

The objective of this study was to determine the objective response rate in patients with platinum-sensitive and platinum-resistant recurrent ovarian cancer to treatment with trabectedin (Yondelis®) administered as a 3-h infusion weekly for 3 weeks of a 4-week cycle. We carried out a multicentre Phase II trial of trabectedin in patients with advanced recurrent ovarian cancer. Trabectedin (0.58 mg m−2) was administered via a central line, after premedication with dexamethasone, to 147 patients as a 3-h infusion weekly for 3 weeks followed by 1-week rest. Major eligibility criteria included measurable relapsed advanced ovarian cancer and not more than two prior platinum-containing regimens. Patients were stratified according to the treatment-free interval (TFI) between having either platinum-sensitive (⩾6 months TFI) or platinum-resistant disease (<6 months TFI)/platinum-refractory disease (progression during first line therapy). In the platinum-sensitive cohort, 62 evaluable patients with measurable disease had an overall response rate (ORR) of 29.0% (95% CI: 18.2–41.9%) and median progression-free survival (PFS) was 5.1 months (95% CI: 2.8–6.2). Four patients with measurable disease per Response Evaluation Criteria in Solid Tumours (RECIST) criteria had no follow-up scans at the end of treatment. In the platinum-resistant/refractory cohort, 79 patients were evaluable with an ORR of 6.3% (95% CI: 2.1–14.2%). Median PFS was 2.0 months (95% CI: 1.7–3.5 months). Two patients with measurable disease per RECIST criteria had no follow-up scans at the end of treatment. The most frequent (⩾2% of patients) drug-related treatment-emergent grade 3/4 adverse events were reversible liver alanine transferase elevation (10%), neutropaenia (8%), nausea, vomiting, and fatigue (5% each). Trabectedin is an active treatment, with documented responses in patients with platinum sensitive advanced relapsed ovarian cancer, and has a manageable toxicity profile

Imatinib mesylate (Gleevec) downregulates telomerase activity and inhibits proliferation in telomerase-expressing cell lines

Imatinib mesylate (IM) is a tyrosine kinase inhibitor, which inhibits phosphorylation of downstream proteins involved in BCR-ABL signal transduction. It has proved beneficial in treating patients with chronic myeloid leukaemia (CML). In addition, IM demonstrates activity against malignant cells expressing c-kit and platelet-derived growth factor receptor (PDGF-R). The activity of IM in the blastic crisis of CML and against various myeloma cell lines suggests that this drug may also target other cellular components. In the light of the important role of telomerase in malignant transformation, we evaluated the effect of IM on telomerase activity (TA) and regulation in various malignant cell lines. Imatinib mesylate caused a dose-dependent inhibition of TA (up to 90% at a concentration of 15 μM IM) in c-kit-expressing SK-N-MC (Ewing sarcoma), SK-MEL-28 (melanoma), RPMI 8226 (myeloma), MCF-7 (breast cancer) and HSC 536/N (Fanconi anaemia) cells as well as in ba/F3 (murine pro-B cells), which do not express c-kit, BCR-ABL or PDGF-R. Imatinib mesylate did not affect the activity of other DNA polymerases. Inhibition of TA was associated with 50% inhibition of proliferation. The inhibition of proliferation was associated with a decrease in the S-phase of the cell cycle and an accumulation of cells in the G2/M phase. No apoptosis was observed. Inhibition of TA was caused mainly by post-translational modifications: dephosphorylation of AKT and, to a smaller extent, by early downregulation of hTERT (the catalytic subunit of the enzyme) transcription. Other steps of telomerase regulation were not affected by IM. This study demonstrates an additional cellular target of IM, not necessarily mediated via known tyrosine kinases, that causes inhibition of TA and cell proliferation

Differences in the pattern and regulation of mineral deposition in human cell lines of osteogenic and non-osteogenic origin

Bone marrow-derived mesenchymal stem cells (MSCs) are widely used as a cellular model of bone formation, and can mineralize in vitro in response to osteogenic medium (OM). It is unclear, however, whether this property is specific to cells of mesenchymal origin. We analysed the OM response in 3 non-osteogenic lines, HEK293, HeLa and NTera, compared to MSCs. Whereas HEK293 cells failed to respond to OM conditions, the 2 carcinoma-derived lines NTera and HeLa deposited a calcium phosphate mineral comparable to that present in MSC cultures. However, unlike MSCs, HeLa and NTera cultures did so in the absence of dexamethasone. This discrepancy was confirmed, as bone morphogenetic protein inhibition obliterated the OM response in MSCs but not in HeLa or NTera, indicating that these 2 models can deposit mineral through a mechanism independent of established dexamethasone or bone morphogenetic protein signalling

Defining the mode, energetics and specificity with which a macrocyclic hexaoxazole binds to human telomeric G-quadruplex DNA

Oxazole-containing macrocycles represent a promising class of anticancer agents that target G-quadruplex DNA. We report the results of spectroscopic studies aimed at defining the mode, energetics and specificity with which a hexaoxazole-containing macrocycle (HXDV) binds to the intramolecular quadruplex formed by the human telomeric DNA model oligonucleotide d(T2AG3)4 in the presence of potassium ions. HXDV binds solely to the quadruplex nucleic acid form, but not to the duplex or triplex form. HXDV binds d(T2AG3)4 with a stoichiometry of two drug molecules per quadruplex, with these binding reactions being coupled to the destacking of adenine residues from the terminal G-tetrads. HXDV binding to d(T2AG3)4 does not alter the length of the quadruplex. These collective observations are indicative of a nonintercalative ‘terminal capping’ mode of interaction in which one HXDV molecule binds to each end of the quadruplex. The binding of HXDV to d(T2AG3)4 is entropy driven, with this entropic driving force reflecting contributions from favorable drug-induced alterations in the configurational entropy of the host quadruplex as well as in net hydration. The ‘terminal capping’ mode of binding revealed by our studies may prove to be a general feature of the interactions between oxazole-containing macrocyclic ligands (including telomestatin) and intramolecular DNA quadruplexes