Preliminary results of a phase II study of oxaliplatin, docetaxel, and bevacizumab as first-line therapy of advanced cancer of the ovary, peritoneum, and fallopian tube

5546

Background: Objectives are to estimate efficacy and safety of a novel taxane/platinum chemotherapy doublet in combination with bevacizumab (B), as first-line treatment of advanced cancer of the ovary, peritoneum or fallopian tube (FT), after initial debulking surgery. Methods: Eligibility criteria included histological confirmation of primary disease, previous debulking surgery, and normal renal, hepatic, hematological, and neurological function. Subjects were treated with 6 cycles of oxaliplatin (85 mg/m2), docetaxel (75 mg/m2) and B (15 mg/kg) Q3W, followed by maintenance B (15 mg/kg Q3W) to complete one year of therapy. The primary endpoint is progression-free survival (PFS) of pts with measurable disease at 1 year. Results: A total of 110 subjects are included in safety and 95 in efficacy analyses (55 with measurable disease). Median age was 58 years. Tumors were mostly ovary as primary site (84%), poorly differentiated (65%), serous adenocarcinoma pathology (73%) and FIGO stage IIIC (68.2%) or IV (14.6%). 61% of subjects were optimally debulked. 95 (86%) of subjects had completed the chemotherapy cycles with 87 of the 95 having started on the B-only maintenance cycles. 85 (77%) subjects have stopped study treatment [including 33 completed study treatment, 29 disease progression, 15 adverse event (AE), 8 other reasons]. The most common grade 3–4 AEs were: neutropenia (39%), leukopenia (11%), hypertension (9%), and fatigue (7%) Grade 3–4 peripheral sensory neuropathy (PSN) occurred in 2 patients (1.3%). There was one case of colonic perforation associated with B. Investigator-determined best overall confirmed response rates were: complete response 32.8%; partial response, 29.1%; stable disease 32.7%; and progressive disease (PD), 1.8%. The 1-year PFS probability is 70.1% (95% C.I., 56.8%-83.4%) in the 55 patients with measurable disease. Conclusions: This preliminary data supports feasibility of this novel regimen, with an acceptable safety profile and a low incidence of PSN and colonic perforation. Preliminary 1-year PFS is promising. The trial completed accrual to 132 patients in August 2008. Updated results will be presented.

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Preliminary safety and efficacy results of a phase II study of oxaliplatin, docetaxel, and bevacizumab as first-line therapy of advanced cancer of the ovary, peritoneum, and fallopian tube

5518

Background: Objectives: Determine safety and estimate efficacy of a novel taxane/platinum chemotherapy (CTX) doublet in conjunction with bevacizumab, as first-line treatment of advanced cancer of the ovary, peritoneum or fallopian tube (FT), after initial debulking surgery. Methods: Treatment: 6 cycles of oxaliplatin (O) (85 mg/m2), docetaxel (D) (75 mg/m2) and bevacizumab (B) (15 mg/kg) Q3W, followed by maintenance B (15 mg/kg Q3W) to complete one year of therapy. Pts were treated until disease progression, unacceptable toxicity, prolonged treatment delay, death, or refusal to continue on study. The primary efficacy endpoint is PFS at 12 months. Results: As of 30 Nov 06, 59 pts (median age 58) were enrolled. Primary sites of disease included 47 ovary, 7 peritoneum, 4 FT. Tumors were mostly poorly differentiated (70%) with a serous adenocarcinoma initial pathology type (81%). Most pts were stage IIIC (40) or IV (17). 64% of pts. were optimally debulked. GOG PS was 0–1 in 56 pts. 58 pts were treated with at least one cycle of CTX. 22 pts. completed six cycles of CTX + B; 14 of these have begun B maintenance Rx. Safety data in available on a total of 283 patient-cycles. Of the 57 pts. with adverse event (AE) data available, 31 (54%) reported at least one grade 3–4 AE, 9 (16%) at least one serious AE (SAE), 54 at least one AE related to CTX (O or D), and 45 reported at least one AE related to B. There have been 8 SAEs related to CTX (O or D): febrile neutropenia (FN) (2), chest pain (1), dehydration (1), lymphopenia (1), neutropenia (1), peripheral sensory neuropathy (PSN) (1), palpitations (1). There have been 7 SAEs related to B: chest pain, colonic fistula, dehydration, FN, palpitations, PSN, vertigo (1 each). There were no B-associated colonic perforations. Of the 59 subjects, 31 (53%) had measurable disease at baseline. One of 31 patients has confirmed progression of disease. Conclusions: This preliminary data supports feasibility of this novel regimen, with an acceptable safety profile. As of December 2006, 75 patients have been enrolled. Updated safety and preliminary efficacy (RR) data will be presented.

No significant financial relationships to disclose.

Identification and characterization of a gene encoding a vertebrate-type carbonic anhydrase in cyanobacteria

A gene (designated ecaA) encoding a vertebrate-like (alpha-type) carbonic anhydrase (CA) has been isolated from two disparate cyanobacteria, Anabaena sp. strain PCC 7120 and Synechococcus sp. strain PCC 7942. The deduced amino acid sequences correspond to proteins of 29 and 26 kDa, respectively, and revealed significant sequence similarity to human CAI and CAII, as well as Chlamydomonas CAHI, including conservation of most active-site residues identified in the animal enzymes. Structural similarities between the animal and cyanobacterial enzymes extend to the levels of antigenicity, as the Anabaena protein cross-reacts with antisera derived against chicken CAII. Expression of the cyanobacterial ecaA is regulated by CO2 concentration and is highest in cells grown at elevated levels of CO2. Immunogold localization using an antibody derived against the ecaA protein indicated an extracellular location. Preliminary analysis of Synechococcus mutants in which ecaA has been inactivated by insertion of a drug resistance cassette suggests that extracellular carbonic anhydrase plays a role in inorganic-carbon accumulation by maintaining equilibrium levels of CO2 and HCO3- in the periplasm.

Factors regulating cryIVB expression in the cyanobacterium--Synechococcus PCC 7942

The expression of the larvicidal Bacillus thuringiensis subsp. israelensis cryIVB gene in cyanobacteria has been suggested to be an effective means of controlling mosquito populations. Using a variety of cryIVB constructs, in this study we have examined the effect of Synechococcus PCC 7942 culture age on intracellular toxin levels and have attempted to determine the mechanisms by which cryIVB gene expression is regulated. The data suggest that specific degradation of the cryIVB mRNA limits toxin production; however, the addition of cyanobacterial 3' untranslated DNA sequences to the cryIVB gene did not improve mRNA stability or toxin levels. An analysis of the cryIVB sequence and comparison of codon usage patterns with highly expressed cyanobacterial genes suggest that inefficient translation and intragenic ribosomal binding sites impede protein synthesis and result in rapid turnover of the toxin mRNA.

Effect of promoter modification on mosquitocidal cryIVB gene expression in Synechococcus sp. strain PCC 7942

The impact of promoter modification on the expression of the mosquitocidal Bacillus thuringiensis subsp. israelensis cryIVB gene when used to transform the cyanobacterium Synechococcus sp. strain PCC 7942 has been examined. Maximal transcript and protein abundances were achieved by the addition of the lacZ promoter upstream of the cryIVB sequence. Replacement of the endogenous corresponding Bacillus sequences with the Synechococcus petF1 promoter, ribosome binding site, and initiation codon also resulted in increased expression of the cryIVB gene relative to the expression obtained with the Bacillus promoter alone but decreased expression relative to the expression achieved with the tandem array of the Bacillus and lacZ promoters. Synechococcus cells carrying plasmids in which the expression of the cryIVB gene was regulated by either the lacZ or the petF1 promoter were readily consumed by first-instar Culex restuans larvae and proved to be toxic for these organisms.