Low-Dose Fulvestrant Maintained Long-Term Complete Remission after Poor Response to Previous Endocrine Therapies in a Patient with Advanced Breast Cancer

We report a case of long-term (9 years) response to 4th-line endocrine treatment with fulvestrant given for advanced breast cancer after no or poor response to prior endocrine therapies. Complete remission was achieved with full dose and maintained even after dose reduction due to unanticipated intensity of mucosal toxicity. Complete remission was temporarily lost after fulvestrant was tentatively withdrawn (63 months after treatment start), but was re-achieved after renewal of half-dose treatment and last reconfirmed 90 months after treatment start. The pharmacokinetic profile provides evidence to hypothesize a unique sensitivity to fulvestrant in this patient which might explain both: toxicity and extraordinary efficacy.

PKB/AKT phosphorylation of the transcription factor Twist-1 at Ser42 inhibits p53 activity in response to DNA damage

Protein kinase B (PKB/Akt) is ubiquitously expressed in cells. Phosphorylation of its multiple targets in response to various stimuli, including growth factors or cytokines, promotes cell survival and inhibits apoptosis. PKB is upregulated in many different cancers and a significant amount of the enzyme is present in its activated form. Here we show that PKB phosphorylates one of the anti-apoptotic proteins--transcription factor Twist-1 at Ser42. Cells expressing Twist-1 displayed inefficient p53 upregulation in response to DNA damage induced by gamma-irradiation or the genotoxic drug adriamycin. This influenced the activation of p53 target genes such as p21(Waf1) and Bax and led to aberrant cell-cycle regulation and the inhibition of apoptosis. The impaired induction of these p53 effector molecules is likely to be mediated by PKB-dependent phosphorylation of Twist-1 because, unlike the wild-type mutant, the Twist-1 S42A mutant did not confer cell resistance to DNA damage. Moreover, phosphorylation of Twist-1 at Ser42 was shown in vivo in various human cancer tissues, suggesting that this post-translational modification ensures functional activation of Twist-1 after promotion of survival during carcinogenesis.

Antiangiogenic drugs in oncology: a focus on drug safety and the elderly - a mini-review

Angiogenesis is essential for normal tissue and even more so for solid malignancies. At present, inhibition of tumor angiogenesis is a major focus of anticancer drug development. Bevacizumab, a humanized antibody against VEGF, was the first antiangiogenic agent to be approved for advanced non-small cell lung cancer, breast cancer and colorectal cancer. The most commonly observed adverse events are hypertension, proteinuria, bleeding and thrombosis. Sunitinib, a small molecule blocking intracellular VEGF, KIT, Flt3 and PDGF receptors, which regulate angiogenesis and cell growth, is approved for the treatment of advanced renal cell cancer (RCC) and malignant gastrointestinal stromal tumor. The most frequent adverse events include hand-foot syndrome, stomatitis, diarrhea, fatigue, hypothyroidism and hypertension. Sorafenib, an oral multikinase inhibitor, is approved for the second-line treatment of advanced RCC and upfront treatment of advanced hepatocellular carcinoma. Most common adverse events with sorafenib are dermatologic (hand-foot skin reaction, rash, desquamation), fatigue, diarrhea, nausea, hypothyroidism and hypertension. More recently, cardiovascular toxicity has increasingly been recognized as a potential adverse event associated with sunitinib and sorafenib treatment. Elderly patients are at increased risk of thromboembolic events when receiving bevacizumab, and potentially for cardiac dysfunction when receiving sunitinib or sorafenib. The safety of antiangiogenic drugs is of special concern when taking these agents for longer-term adjuvant or maintenance treatment. Furthermore, newer investigational antiangiogenic drugs are briefly reviewed.

Phase Ib study of weekly mammalian target of rapamycin inhibitor ridaforolimus (AP23573; MK-8669) with weekly paclitaxel

BACKGROUND

The additive cytotoxicity in vitro prompted a clinical study evaluating the non-prodrug rapamycin analogue ridaforolimus (AP23573; MK-8669; formerly deforolimus) administered i.v. combined with paclitaxel (PTX; Taxol).

MATERIALS AND METHODS

Patients with taxane-sensitive solid tumors were eligible. The main dose escalation foresaw 50% ridaforolimus increments from 25 mg with a fixed PTX dose of 80 mg/m(2), both given weekly 3 weeks in a 4-week cycle. Collateral levels with a lower dose of either drug were planned upon achievement of the maximum tolerated dose in the main escalation. Pharmacodynamic studies in plasma, peripheral blood mononuclear cells (PBMCs) and skin biopsies and pharmacokinetic (PK) interaction studies at cycles 1 and 2 were carried out.

RESULTS

Two recommended doses were determined: 37.5 mg ridaforolimus/60 mg/m(2) PTX and 12.5 mg/80 mg/m(2). Most frequent toxic effects were mouth sores (79%), anemia (79%), fatigue (59%), neutropenia (55%) and dermatitis (48%). Two partial responses were observed in pharyngeal squamous cell and pancreatic carcinoma. Eight patients achieved stable disease > or =4 months. No drug interaction emerged from PK studies. Decrease of eukaryotic initiation factor 4E-binding protein1 (4E-BP1) phosphorylation was shown in PBMCs. Similar inhibition of phosphorylation of 4E-BP1 and mitogen-activated protein kinase was present in reparative epidermis and vascular tissues, respectively.

CONCLUSION

Potential antiangiogenic effects and encouraging antitumor activity justify further development of the combination.

Clinical development of namitecan (ST1968), a novel camptothecin derivative with high antitumor activity: Phase I clinical data

2570

Background: Namitecan is a new water-soluble camptothecin analogue which showed high antitumor activity in preclinical models. Aim of this trial was to determine safety, PK profile and activity in adult patients with advanced solid tumors. Methods: The dose escalation started at 2.5 mg i.v. on days 1 and 8 of a 21 day cycle (D1, D8 Q21D) and increased according to 3+3 cohort design depending on the observed toxicity. Dose limiting toxicity (DLT) definitions were: ANC <0.5x109/L for >5 days; PLT ≥ Grade 3 (CTC V3); grade ≥2 liver/renal toxicity not recovered by D22; any non-hematologic toxicity ≥ Grade 3; D8 dose skipping due to toxicity. Maximum tolerated dose (MTD) and recommended dose (RD) were the primary end-points. Blood and urine samples were collected at cycle 1 for PK evaluation. Results: 31 pts (11 endometrial ca., 5 CRC, 5 ovarian ca., 2 NSCLC, 8 other) have been included, with 6 dose levels evaluated (2.5; 5; 10; 15; 17.5 and 20 mg). 17.5 mg was introduced later when 2/7 DLTs at 20 mg were observed (ANC G4>5days, one with D8 skipping). At 17.5mg 2/4 pts experienced DLTs (ANC G4; D8 skipped). Uncomplicated neutropenia and thrombocytopenia were the most relevant G3/4 hematological toxicities. Other toxicities were mild or moderate asthenia, fatigue and alopecia. The MTD was defined at 17.5 mg and the RD was 15 mg. Stable disease ≥ 6 cycles was recorded in 6 pts (2 stable diseases ≥ 10 cycles). PK was linear and data suggest an entero-hepatic recirculation. No metabolites were found in plasma and the product resulted poorly excreted into urine. Conclusions: The MTD and RD of D1, D8 Q21D schedule have been identified. The study will continue with the evaluation of MTD and RD of a single administration per cycle (D1 Q21D), to optimize the schedule of treatment.

[Table: see text]

PML tumor suppressor is regulated by HIPK2-mediated phosphorylation in response to DNA damage

The promyelocytic leukemia (PML) tumor suppressor protein, a central regulator of cell proliferation and apoptosis, is frequently fused to the retinoic acid receptor-alpha (RARalpha) in acute PML. Here we show the interaction of PML with another tumor suppressor protein, the serine/threonine kinase homeodomain-interacting protein kinase (HIPK2). In response to DNA damage, HIPK2 phosphorylates PML at serines 8 and 38. Although HIPK2-mediated phosphorylation of PML occurs early during the DNA damage response, the oncogenic PML-RARalpha fusion protein is phosphorylated with significantly delayed kinetics. DNA damage or HIPK2 expression leads to the stabilization of PML and PML-RARalpha proteins. The N-terminal phosphorylation sites contribute to the DNA damage-induced PML SUMOylation and are required for the ability of PML to cooperate with HIPK2 for the induction of cell death.

Adipose macrophage infiltration is associated with insulin resistance and vascular endothelial dysfunction in obese subjects

OBJECTIVE

Experimental studies suggest that adipose inflammation is etiologically linked to obesity-induced systemic disease. Our goal was to characterize the state of inflammation in human fat in relation to vascular function and metabolic parameters in obese individuals.

METHODS AND RESULTS

We collected subcutaneous abdominal fat in 77 obese subjects (BMI >or=30 kg/m(2)) and quantified adipose macrophage population using targeted immunohistochemistry. Brachial artery vasodilator function was examined using high-resolution vascular ultrasound. In 50 subjects, an inflamed adipose phenotype characterized by tissue macrophage accumulation in crown-like structures was associated with systemic hyperinsulinemia and insulin resistance (HOMA-IR 5.5+/-4.5 versus 2.6+/-1.9, P=0.002) and impaired endothelium-dependent flow-mediated vasodilation (8.5+/-4.4% versus 10.8+/-3.8%, P<0.05), as compared to subjects with quiescent noninflamed adipose architecture (n=27). Macrophage retention in fat was linked to upregulated tissue CD68 and tumor necrosis factor (TNF)-alpha mRNA expression in addition to increased plasma hs-CRP.

CONCLUSIONS

In a cohort of obese subjects, we demonstrate that proinflammatory changes in adipose tissue are associated with systemic arterial dysfunction and insulin resistance. These findings suggest that adipose inflammation may be linked to vascular injury and increased cardiovascular risk in obese subjects.

Pin1 interacts with c-Myb in a phosphorylation-dependent manner and regulates its transactivation activity

Activity and stability of the proto-oncogene c-Myb are regulated by post-translational modifications, though the molecular mechanisms underlying such control are only partially understood. Here we describe the functional interaction of c-Myb with Pin1, an isomerase that binds to phosphorylated Ser/Thr-Pro motifs. We found that co-expression of c-Myb and Pin1 led to a net increase of c-Myb transactivation activity, both on reporter constructs as well as on an endogenous target gene. DNA-binding studies revealed that Pin1 did not increase the association of c-Myb with its response element in DNA. The increase of c-Myb transactivation activity was strictly dependent on the presence of an active catalytic center in Pin1. We provide evidence that c-Myb and Pin1 physically interacted, both upon ectopic expression of the proteins in HEK-293 cells as well as in the more physiological setting of HL60 cells, where c-Myb and Pin1 are resident proteins. By point mutating each individual Ser/Thr-Pro motif in c-Myb as well as by using deletion mutants we show that S528 in the EVES-motif was the docking site for Pin1. Mass spectrometry confirmed that S528 is phosphorylated in vivo. Finally, functional studies showed that mutation of S528 to alanine almost abolished the increase of transactivation activity by Pin1. This study reveals a new paradigm by which phosphorylation controls c-Myb function.

Relation of cumulative weight burden to vascular endothelial dysfunction in obesity

Although excess fat mass is linked to increased cardiovascular risk, the relation between vascular phenotype and degree of obesity in high weight categories is unknown. We examined brachial artery vasomotor responses using ultrasound in 203 consecutive patients with severe obesity (mean age 44 +/- 11 years; body mass index [BMI] 46 +/- 9 kg/m(2), range 30 to 72; and body weight 128 +/- 29 kg, range 69 to 207). We studied a unique population in which 71% of subjects were characterized as morbidly obese (BMI > or =40 kg/m(2)), which included a 31% group of super-obese subjects (BMI > or =50 kg/m(2)). Brachial artery flow-mediated dilation (FMD) and nitroglycerin-mediated dilation were examined as measures of endothelium-dependent and -independent dilation, respectively, in relation to clinical, hemodynamic, and metabolic variables. Endothelial function was significantly impaired in the highest compared with the lowest tertile of body weight (FMD 6.5 +/- 4.6% vs 9.8 +/- 4.8%, p <0.001), whereas nitroglycerin-mediated dilation was similar in all groups. Univariate correlates of FMD were gender, weight, waist circumference, BMI, diastolic blood pressure, and creatinine. In multivariate analysis, weight was a strong independent significant predictor of FMD (beta = -0.23, p = 0.005) in addition to gender. Within an overweight population, cumulative weight burden remains strongly linked to progressive arterial dysfunction. In conclusion, these results suggest that cardiovascular risks intensify with higher degrees of obesity and underscore the importance of therapeutic weight loss interventions.

Phase 1b study defining the optimal dosing combinations of the mTOR inhibitor AP23573 and Paclitaxel (PTX)

3509

Background: AP23573 is a novel mTOR inhibitor with demonstrated anti-tumor activity in clinical trials. In vitro, AP23573 exhibits at least additive anti-proliferative activity in combination with a variety of agents including taxanes. This trial studied the combination of AP23573 and paclitaxel (PTX) in patients with advanced solid tumors. Methods: This was a modified, sequential (3+3) dose finding study with starting doses of 25 mg AP23573 i.v. and 80 mg/m2 PTX i.v. as Dose Level 1 (DL1) on days 1, 8 and 15 of a 28 day cycle. Doses of either drug were adjusted in successive cohorts. Blood samples and skin biopsies were collected for pharmacokinetic (PK) and pharmacodynamic (PD) studies. Dose limiting toxicity definitions included neutrophils <500/μL; thrombocytopenia = Grade 3 (CTC), any non- hematologic toxicities = Grade 2; missing 2 consecutive doses due to any toxicity. For PK and PD analysis, AP23573 and PTX were administered one day apart at the start of Cycle 1, reversing the sequence at Day 8. Results: Enrollment is complete and 29 patients with a variety of tumors (sarcoma, pancreatic, H&N, melanoma, thymoma) have been treated. Grade 3 thrombocytopenia and Grade 2 mouth sores were seen at DL1 as well as missed doses due to moderate (Grade 2) neutropenia. Adverse events include mouth sores and fatigue which were mild and reversible. Available PK data for AP23573 and PTX suggest no interaction. PD analysis in peripheral blood mononuclear cells demonstrates no interference by PTX on mTOR inhibition by AP23573. PD data in skin biopsies are forthcoming. Both 12.5 mg AP23573/80mg/m2 PTX and 37.5mg AP23573/60mg/m2 PTX are maximal dose combinations that appear to be well tolerated. Activity has been observed at multiple AP23573 mg/PTX mg/m2 dose levels (25/60, 12.5/80, 25/80). Five patients have been on study for >4 cycles, including 2 patients with partial responses (H&N and pancreatic). Conclusions: Combined therapy with AP23573 and PTX is safe. It is notable that evidence of anti-tumor activity was observed at modest doses of each drug when in combination. Combinations of these agents at both doses cited would be recommended for evaluation in trials examining efficacy in specific tumors.

No significant financial relationships to disclose.

Concerted escalation of dose and dosing duration in a phase I study of the oral camptothecin gimatecan (ST1481) in patients with advanced solid tumors

BACKGROUND

Gimatecan is an orally bioavailable camptothecin analogue with preclinical findings of promising antitumor activity. A phase I design of concerted dose escalation and dosing duration was implemented to assess the potential schedule dependency of tolerability that emerged from animal studies.

PATIENTS AND METHODS

Gimatecan was given daily for five consecutive days per week for 1, 2 or 3 weeks every 28 days. Plasma levels of total gimatecan were measured on the first and the last day of treatment in each schedule.

RESULTS

Overall, 108 patients were treated with 0.8-7.2 mg/m(2) of gimatecan per cycle. The main toxicity was myelosuppression with dose-limiting thrombocytopenia. In the 1-, 2- and 3-week schedule, the maximum tolerated doses were 4.5, 5.6 and 6.4 mg/m(2). Diarrhea and asthenia were of low grade and of minor clinical relevance, while the higher incidence of nausea and vomiting in the 1-week schedule required the use of antiemetic prophylaxis. Due to the prolonged half-life (approximately 77 h), the plasma concentration of gimatecan increased from the first to the last day of dosing. Six partial responses were observed.

CONCLUSIONS

Tolerability of gimatecan was schedule dependent. Further testing with schedules taking into account its long persistence in human plasma is worthwhile.

A phase II trial of the novel oral camptothecin gimatecan (G) in women with anthracycline (A) and taxane (T) pre-treated advanced breast cancer

662

Background: Gimatecan (G) is a new oral camptothecin with a favourable therapeutic index in several tumor xenograft models and with documented antitumor activity in breast, endometrial and NSCLC cancer in Phase I. A Phase II trial was implemented to determine the antitumor activity of G in women with pre-treated metastatic breast cancer (MBC). Methods: A Simon 2-step design was used: patients with MBC who failed A & T were eligible. Treatment failure was defined as disease progressing after receiving both A and T (adjuvant or metastatic setting). All patients had ECOG 0–1. Baseline neuropathy > gr 1 or CNS metastases were criteria of exclusion. G was administered for 5 days every week on weeks 1 & 2 q4weeks at 4–5 mg/m2 total dose per cycle. Results: To date, 21 patients have received 67 cycles of G (median 3); 18 are evaluable for the 1st step analysis. Median age was 53 years (range, 32–70), all had received A & T prior treatment. The initial dose of 5 mg/m2 was reduced to 4 mg/m2 after treating the first 7 cases due to hematological toxicity (thrombocytopenia G3 30% and neutropenia G3–4 40%) that prevented the planned monthly retreatment. The toxicity at 4 mg/m2 included thrombocytopenia (% of cycles with any grade: 36%, G3 9%); neutropenia (G3 18%), diarrhea (1 case), nausea (81%, G3 18%), vomiting (G1 18%), and asthenia (G1 36%). To date, three confirmed partial responses (PR) lasting respectively 5.5, 5.7+, and 9.4+ months and two unconfirmed PR were observed in visceral and nodal sites. Accrual into step 2 is proceeding. Conclusions: Gimatecan at a dose of 4 mg/m2 is well tolerated and active. The antitumor activity of 27% observed in the first step of the study is unusual for camptothecins and prompted to continue to the second step and complete the ongoing enrolment of 43 patients overall.

[Table: see text]

Caveolin-1 interacts with the chaperone complex TCP-1 and modulates its protein folding activity

We report that caveolin-1, one of the major structural protein of caveolae, interacts with TCP-1, a hetero-oligomeric chaperone complex present in all eukaryotic cells that contributes mainly to the folding of actin and tubulin. The caveolin-TCP-1 interaction entails the first 32 amino acids of the N-terminal segment of caveolin. Our data show that caveolin-1 expression is needed for the induction of TCP-1 actin folding function in response to insulin stimulation. Caveolin-1 phosphorylation at tyrosine residue 14 induces the dissociation of caveolin-1 from TCP-1 and activates actin folding. We show that the mechanism by which caveolin-1 modulates TCP-1 activity is indirect and involves the cytoskeleton linker filamin. Filamin is known to bind caveolin-1 and to function as a negative regulator of insulin-mediated signaling. Our data support the notion that the caveolin-filamin interaction contributes to restore insulin-mediated phosphorylation of caveolin, thus allowing the release of active TCP-1.

Dose-finding study of weekly docetaxel, anthracyclines plus fluoropyrimidines as first-line treatment in advanced breast cancer

BACKGROUND

The efficacy and safety of prolonged fluoropyrimidines, either intravenously or orally, prompted their integration with taxanes and anthracyclines in the treatment of advanced breast cancer (ABC). We conducted three subsequent dose-finding studies on first-line chemotherapy in ABC with anthracyclines, either epirubicin (E) or doxorubicin (A), and docetaxel (T), both given on days 1 and 8 every 3 weeks, plus continuous infusion (CI) 5-fluorouracil (F) or capecitabine (X).

PATIENTS AND METHODS

Sixty-two patients (37% dominant visceral disease, 48% locally advanced disease, 45% two or more sites involved), received different doses of T (60--80 mg/m(2)), A (40--50 mg/m(2)) or E (60--90 mg/m(2)) and X (1,650 and 2,000 mg/m(2)), or CI F at a fixed daily dose of 200 mg/m(2). Cardiac function was monitored at baseline and then every four cycles by echocardiography.

RESULTS

The median number of cycles per patient with all regimens was four (range one to eight). Haematological and gastrointestinal toxicity defined the maximum tolerated doses, at T-80/E-90 mg/m(2) with TEF, T-70/A50/X-2,000 mg/m(2) with TAX and T-70/E-80/X-1,650 mg/m(2) with TEX. Two patients treated with TEF developed transient cardiac toxicity (dilatative cardiomyopathy and coronary subtotal stenosis requiring stenting) after cumulative E doses of 400 mg and 1,100 mg/m(2), respectively. Fifty-nine patients were evaluable for response; the overall response rates (ORR) were comparable between regimens (54% with TEF, 71% with TAX and 86% with TEX), with an 81% ORR in 31 patients with locally advanced disease.

CONCLUSIONS

The addition of fluoropyrimidines to weekly, intermittent ET is well tolerated and active in ABC.

Carotid endarterectomy--An evidence-based review: Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology

OBJECTIVE

To assess the efficacy of carotid endarterectomy for stroke prevention in asymptomatic and symptomatic patients with internal carotid artery stenosis. Additional clinical scenarios, such as use of endarterectomy combined with cardiac surgery, are also reviewed.

METHODS

The authors selected nine important clinical questions. A systematic search was performed for articles from 1990 (the year of the last statement) until 2001. Additional articles from 2002 through 2004 were included using prespecified criteria. Two reviewers also screened for other relevant articles from 2002 to 2004. Case reports, review articles, technical studies, and single surgeon case series were excluded.

RESULTS

For several questions, high quality randomized clinical trials had been completed. Carotid endarterectomy reduces the stroke risk compared to medical therapy alone for patients with 70 to 99% symptomatic stenosis (16% absolute risk reduction at 5 years). There is a smaller benefit for patients with 50 to 69% symptomatic stenosis (absolute risk reduction 4.6% at 5 years). There is a small benefit for asymptomatic patients with 60 to 99% stenosis if the perioperative complication rate is low. Aspirin in a dose of 81 to 325 mg per day is preferred vs higher doses (650 to 1,300 mg per day) in patients undergoing endarterectomy.

CONCLUSIONS

Evidence supports carotid endarterectomy for severe (70 to 99%) symptomatic stenosis (Level A). Endarterectomy is moderately useful for symptomatic patients with 50 to 69% stenosis (Level B) and not indicated for symptomatic patients with <50% stenosis (Level A). For asymptomatic patients with 60 to 99% stenosis, the benefit/risk ratio is smaller compared to symptomatic patients and individual decisions must be made. Endarterectomy can reduce the future stroke rate if the perioperative stroke/death rate is kept low (<3%) (Level A). Low dose aspirin (81 to 325 mg) is preferred for patients before and after carotid endarterectomy to reduce the rate of stroke, myocardial infarction, and death (Level A).