What is the evidence for rechallenging with anthracyclines or taxanes in metastatic breast cancer? A review of the data

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Background: Anthracyclines and taxanes are widely used in the adjuvant setting for high risk, early stage breast cancer. This raises the issue of what is the optimal therapy for those patients who relapse, and what the potential role, if any, there is for rechallenge with these agents. The current evidence base for rechallenging with anthracyclines/anthracediones and taxanes in metastatic breast cancer (MBC) is examined in this study. Methods: Medline/Pubmed database searches were performed upto October 2008 to identify studies in which patients (pts) were rechallenged with anthracyclines/anthracediones or taxanes in MBC. Results: The efficacy data, as well as the safety data relating to neurotoxicity and cardiotoxicity from these studies, are summarized in the Table. Twenty-seven studies were identified (20=anthracycline/anthracedione, 7= taxane) of which only two were prospective studies. Both were small (n= 74 & 51) and related to anthracycline rechallenging. Conclusions: Evidence exists to support rechallenging with anthracyclines and taxanes. However, there are few prospective data on reexposure to taxanes and no data comparing anthracyclines versus taxanes following adjuvant exposure to both agents, supporting the need for clinical trials in this area. Such trials should ideally incorporate a cross-over design at treatment failure, which would shed light on the optimal sequence in which these agents should be administered.

[Table: see text]

No significant financial relationships to disclose.

002. REGULATION OF PLURIPOTENCY AND CELL CYCLE IN FETAL GERM CELLS

The germ cell lineage is unique in that it must ensure that the genome retains the complete developmental potential (totipotency) that supports development in the following generation. This is achieved through a number of mechanisms that prevent the early germ cell lineage from somatic differentiation and promote the capactity for functional totipotency. Part of this process involves the retained germ line expression of key genes that regulate pluripotency in embryonic stem cells, embryonic germ cells and some embryonal carcinoma cells, the stem cells of testicular tumours. Despite this, germ cells are not intrinsically pluripotent and must differentiate along the male or female pathways, a process which requires commitment of the bi-potential primordial germ cells to the spermatogenic (male) pathway and their entry into mitotic arrest, or to the oogenic pathway (females) and entry into meiosis. This involves robust regulation of regulatory networks controlling pluripotency, cell cycle and sex specific differentiation. Our work aims to further understand the mechanisms controlling differentiation, pluripotency and cell cycle in early male and female germ cells. Our data shows that mitotic arrest of male germ cells involves strict regulation of the G1-S phase check-point through the retinoblastoma protein. In addition, suppression of pluripotency in differentiating male germ cells involves post-transcriptional regulation of OCT4, transcriptional regulation of Sox2 and Nanog and methylation of the Sox2 and Nanog promoters. Further understanding of these processes promises to lead to a greater understanding of the molecular mechanisms underlying control of pluripotency, cell cycle and differentiation in the germ line and the initiation of germ cell derived testis tumours.

Objective response rate in a phase II multicenter trial of pertuzumab (P), a HER2 dimerization inhibiting monoclonal antibody, in combination with trastuzumab (T) in patients (pts) with HER2-positive metastatic breast cancer (MBC) which has progressed during treatment with T

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Background: T and P bind to different epitopes on the extra cellular domain of HER2. Unlike T, P binds to the dimerization domain and blocks homo- and hetero-dimerization of HER2 with other HER kinase family members. Xenograft models support the hypothesis that the complementary mechanisms of action could result in augmented efficacy when T and P are combined. Methods: Two-stage design, criteria to proceed to the 2nd stage were: ≥ 2 partial responses (PR) or 1 PR and 12 stable disease (SDs) or 13 SDs. Eligibility included: measurable, centrally-tested HER2 positive breast cancer; up to 3 lines of prior chemotherapy plus T (including adjuvant chemotherapy plus T); disease progression during T as most recent treatment for metastatic disease; baseline left ventricular ejection fraction (LVEF) ≥ 55% and no decrease of LVEF to below 50% during prior T treatment. Consenting Pts received T i.v. weekly or every 3 weeks at 2 mg/kg or 6 mg/kg respectively (with re-loading dose if required) plus 420mg fixed dose of P i.v. every 3 weeks following loading dose 840mg. Study treatment was initiated within 9 weeks of the last dose of T given as most recent therapy. An independent data safety monitoring board has overseen the 1st stage safety data. Results: Recruitment into 1st stage is complete. The main adverse events were diarrhea (71%), fatigue (46%), nausea/vomiting (38%) and rash (25%). Most AE’s were mild to moderate (there was 1 case of Grade 3 diarrhea) and none was treatment-limiting. There were no clinical cardiac events, and central review revealed no case of fall in LVEF of ≥10% and to ≤50%. Response status: 5 confirmed PR (21%); 12 SD (50%). Responses have been observed in lymph node and liver metastases. Recruitment into the 2nd stage of the trial has commenced. Conclusions: The combination of the P and T is active and well tolerated in patients with pre-treated HER2 positive breast cancer which has progressed during treatment with T.

No significant financial relationships to disclose.

Cemento-osseous dysplasia in Jamaica: review of six cases

Six cases of cemento-osseous dysplasia (COD) of the jaw bone in Jamaicans are reviewed. Five were documented over a 15-year period (1980-1995). These include a case of florid cemento-osseous dysplasia (previously called gigantiform cementoma). Three of the initial cases were histologically diagnosed as gigantiform cementoma. There was no indication in the patient's case file whether these were familial or non-familial. The other two cases were diagnosed histologically as periapical cemento-osseous dysplasia and cementoblastoma respectively. Based on the current understanding of the nature of florid-cemento-osseous dysplasia (FLCOD), a new case was diagnosed as such solely on radiological findings. This single case of FLCOD is reported and discussed against the background of other cemento-osseous lesions. Special emphasis is placed on the radiology of COD in this paper. The confirmative role of radiology without the need for histophathology and treatment for asymptomatic FLCOD is emphasized.

Impact of neutropenia on delivering planned adjuvant chemotherapy: UK audit of primary breast cancer patients

The UK audit was undertaken in primary breast cancer patients receiving adjuvant chemotherapy to: (1) record the incidence of neutropenic events (hospitalisation due to febrile neutropenia, dose delay of ⩾1 week or dose reduction of ⩾15% due to neutropenia); (2) evaluate the impact of neutropenic events on overall dose intensity (DI) received and (3) review the use of granulocyte colony-stimulating factor (G-CSF) in clinical practice. Data from 422 patients with Stage I–III breast cancer were collected from 15 centres. Cyclophosphamide, methotrexate and 5-fluorouracil(CMF)- or anthracycline-based regimens were the most commonly used. Only 5.2% of patients received G-CSF. Overall, 29% of patients experienced a neutropenic event, most frequently dose delay. Neutropenic events had a significant impact on the ability to deliver planned DI. Out of 422 patients, 17% did not achieve 85% of their planned DI; due to neutropenia in 11% of patients. Of the neutropenic patients receiving CMF- or anthracycline-based regimens, around 40 and 32% of patients, respectively, did not achieve 85% of their planned DI. Patients who experienced one neutropenic event had a higher risk of a second event. During adjuvant chemotherapy of primary breast cancer, neutropenic events are common, likely to occur in subsequent chemotherapy cycles, and have a significant impact on receiving planned DI.

Antibacterial and antifungal activity of Indonesian ethnomedical plants

Methylene chloride and methanol extracts of 20 Indonesian plants with ethnomedical uses have been assessed for in vitro antibacterial and antifungal properties by disk diffusion method. Extracts of the six plants: Terminalia catappa, Swietenia mahagoni Jacq., Phyllanthus acuminatus, Ipomoea spp., Tylophora asthmatica and Hyptis brevipes demonstrated high activity in this bioassay system. These findings should stimulate the search for novel, natural product such as new antibacterial and antifungal agents.

Xeloda and Taxotere: a review of the development of the combination for use in metastatic breast cancer

Docetaxel (Taxotere) and capecitabine (Xeloda) demonstrate synergy in pre-clinical studies and both show high single-agent efficacy in metastatic breast cancer patients previously treated with an anthracycline. The two drugs used in combination in a similar group of patients have been evaluated in a randomised phase III trial comparing this combination with single-agent docetaxel. The results of this study indicate the combination arm to be favourable with significantly superior median time to disease progression (6.1 vs 4.2 months, hazard ratio 0.652, p=0.0001), objective response rate and overall survival without a significant increase in the overall incidence of treatment related adverse effects. This combination of docetaxel and capecitabine provides improved survival prospects for patients with metastatic breast cancer. Ongoing studies will provide further data to optimise the scheduling and use of this combination in the future.

21. The adjuvant treatment of breast cancer

Risk of relapse of breast cancer depends largely on tumour features: size, grade and, particularly, lymph node status. Adjuvant systemic therapies reduce risk of relapse and death, as shown in several meta-analyses. Relative risk reductions are similar across different prognostic groups but the absolute benefits are greater in those with a worse prognosis. Combination chemotherapy is superior to single agent regimens but longer duration (>6 months) gives no additional benefit compared with six months of therapy. Benefits from adjuvant chemotherapy diminish with the age of the patient. CMF type regimens have been most widely used: anthracyclines can reduce risk of relapse by 12% (an absolute survival benefit of about 3%) but with greater toxicity. Early trials of taxoids look promising but benefit was seen only in those with ER- tumours. Tamoxifen is the most extensively used endocrine adjuvant therapy, and is associated with a reduction in risk of death of 26% independent of age or menopausal status but only in those with ER+ tumours. Aromatase inhibitors are effective only in postmenopausal women and, although the early results with anastrozole look promising, long-term efficacy and toxicity studies are presently lacking, so five years of tamoxifen is standard treatment for women with ER+ tumours.

A novel apoptotic interaction between HSV-1 and human corneal epithelial cells

PURPOSE

Herpes simplex virus type 1 (HSV-1) infects the cornea possibly causing blindness. The specific mechanisms of herpetic keratitis are unclear. We aimed to investigate whether HSV-1 would up- or down-regulate the apoptotic pathway of human corneal epithelial (HCE) cells.

METHODS

HSV-1 infection of HCE and Vero cells was demonstrated (immunofluorescence) and apoptotic gene expression was quantified (ribonuclease protection assay). Caspase 8 protein activity (colorimetric assay) was quantified and compared to caspase 8 mRNA amounts from RPA experiments. The apoptotic index of HSV-1 infected HCE and Vero cells (apoptotic index = % of apoptotic cells in infected samples/mock treated samples) was obtained and compared to gene expression.

RESULTS

A down-regulation in apoptotic gene expression was observed in HSV-1 infected HCE cells in contrast to Vero cells (infected and mock treated). Caspase 8 protein levels mirrored caspase 8 mRNA levels in HSV-1 infected HCE cells. The apoptotic index also supports this down-regulation. HSV-1 infected human corneal epithelial cells and Vero cells at similar rates.

CONCLUSION

HSV-1 down-regulates the apoptotic pathway of human corneal epithelial cells. This down-regulation of apoptotic gene expression seems to be cell specific. Also infectivity is excluded in playing a role in regulation of the apoptotic pathway because HSV-1 replicated at similar rates in HCE and Vero cells.

Doxorubicin-paclitaxel: a safe regimen in terms of cardiac toxicity in metastatic breast carcinoma patients. Results from a European Organization for Research and Treatment of Cancer multicenter trial

BACKGROUND

The potential cardiotoxicity of the doxorubicin-paclitaxel regimen, when paclitaxel is given shortly after the end of the anthracycline infusion, is an issue of concern, as suggested by small single institution Phase II studies.

METHODS

In a large multicenter Phase III trial, 275 anthracycline naive metastatic breast carcinoma patients were randomized to receive either doxorubicin (60 mg/m(2)) followed 30 minutes later by paclitaxel (175 mg/m(2) 3-hour infusion; AT) or a standard doxorubicin-cyclophosphamide regimen (AC; 60/600 mg/m(2)). Both treatments were given once every 3 weeks for a maximum of six cycles. Close cardiac monitoring was implemented in the study design.

RESULTS

Congestive heart failure (CHF) occurred in three patients in the AT arm and in one patient in the AC arm (P = 0.62). Decreases in left ventricular ejection fraction to below the limit of normal were documented in 33% AT and 19% AC patients and were not predictive of CHF development.

CONCLUSIONS

AT is devoid of excessive cardiac risk among metastatic breast carcinoma patients, when the maximum planned cumulative dose of doxorubicin does not exceed 360 mg/m(2).

Variations in treatment and survival in breast cancer

To achieve optimum quality of care for women with breast cancer in the UK, uniformity of care in accordance with consensus guidelines is needed. This review highlights variations in provision of care for women with breast cancer, with particular emphasis on care received in the UK, examines differences in survival, and discusses the factors that may underlie these differences. Strong variation in treatment was identified, which appeared to affect survival significantly. These findings reinforce the need for women with breast cancer to be treated by dedicated specialists working within a multidisciplinary team to provide a high standard of care.

Motexafin gadolinium: a redox active drug that enhances the efficacy of bleomycin and doxorubicin

The effect of motexafin gadolinium (MGd), a redox mediator, on tumor response to doxorubicin (Dox) and bleomycin (Bleo) was investigated in vitro and in vivo. MES-SA human uterine sarcoma cells were studied in vitro using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide viability assay. Rif-1, a murine fibrosarcoma cell line, was studied using a clonogenic survival assay. Tumor growth delay assays were performed using the EMT-6 murine mammary sarcoma cell line in BALB/c mice. MGd (25-100 microM) produced dose-dependent enhancement of Bleo cytotoxicity to MES-SA cells. The IC(50) for Bleo was reduced by approximately 10-fold using 100 microM MGd. In clonogenic assays using Rif-1 cells, MGd enhanced the activity of Bleo approximately 1000-fold. This effect was shown to be mediated, in part, by MGd inhibition of potentially lethal damage repair. MGd enhanced the tumor response to bleomycin and Dox in vivo. MGd had no significant effect on the systemic exposure to Dox (expressed in terms of the plasma area under the curve, 0-24 h) and did not increase Dox myelosuppression. MGd enhanced the effectiveness of the redox active drugs, Bleo and Dox.

Randomized, open-label, phase II trial of oral capecitabine (Xeloda) vs. a reference arm of intravenous CMF (cyclophosphamide, methotrexate and 5-fluorouracil) as first-line therapy for advanced/metastatic breast cancer

BACKGROUND

Oral capecitabine was evaluated in terms of overall response rate, safety, and tolerability as first-line therapy in women aged > or = 55 years with advanced/metastatic breast cancer.

PATIENTS AND METHODS

Ninety-five patients were randomized (2:1) to either intermittent oral capecitabine 1,255 mg/m2 twice daily (two weeks' treatment followed by a one-week rest period) or intravenous CMF (cyclophosphamide. methotrexate, 5-fluorouracil [5-FU]) administered every three weeks.

RESULTS

The overall response rate in the capecitabine group was 30% (95% confidence interval (95% CI): 19%-43%), including three complete responses (5%). The response rate observed in the CMF group was 16% (95% CI: 5%-33%), with no complete responses. Median time to disease progression was 4.1 months with capecitabine and 3.0 months with CME. Survival was similar in the two treatment groups (median 19.6 months with capecitabine. 17.2 months with CMF). The safety profiles were different for capecitabine and CMF. However, both regimens were generally well tolerated and treatment interruption and/or dose modification was effective in managing toxicities associated with capecitabine. Alopecia and myelosuppression were rare in patients receiving capecitabine while diarrhea and hand-foot syndrome were more common. Treatment interruption and/or individual dose adjustment of capecitabine was required in 34% of patients and was generally effective in managing adverse events. Treatment was stopped owing to toxicity in 16% of patients in the capecitabine arm. The incidence of deaths during or within 28 days of stopping study treatment was 8% and 6% in the capecitabine and CMF arms, respectively.

CONCLUSIONS

An oral, twice-daily regimen of capecitabine is effective and well tolerated when used as first-line chemotherapy in older patients (> or = 55 years) with advanced/metastatic breast cancer, and is suitable for outpatient therapy.

Multicenter phase Ib/II trial of the radiation enhancer motexafin gadolinium in patients with brain metastases

PURPOSE

Motexafin gadolinium is a magnetic resonance imaging (MRI)--detectable redox active drug that localizes selectively in tumor cells and enhances the effect of radiation therapy. This phase Ib/II trial of motexafin gadolinium, administered concurrently with 30 Gy in 10 fractions whole-brain radiation therapy (WBRT), was conducted to determine maximum-tolerated dose (MTD), dose-limiting toxicity, pharmacokinetics, and biolocalization in patients with brain metastases. Additional endpoints were radiologic response rate and survival.

PATIENTS AND METHODS

Motexafin gadolinium was administered before each radiation treatment in this open-label, multicenter, international trial. In phase Ib, drug dose was escalated until the MTD was exceeded. In phase II, drug was evaluated in a narrow dose range.

RESULTS

In phase Ib, the motexafin gadolinium dose was escalated in 39 patients (0.3 mg/kg to 8.4 mg/kg). In phase II, 22 patients received 5 mg/kg to 6.3 mg/kg motexafin gadolinium. Ten once-daily treatments were well tolerated. The MTD was 6.3 mg/kg, with dose-limiting reversible liver toxicity. Motexafin gadolinium's tumor selectivity was established using MRI. The radiologic response rate was 72% in phase II. Median survival was 4.7 months for all patients, 5.4 months for recursive partitioning analysis (RPA) class 2 patients, and 3.8 months for RPA class 3 patients. One-year actuarial survival for all patients was 25%.

CONCLUSION

Motexafin gadolinium was well tolerated at doses up to 6.3 mg/kg, was selectively accumulated in tumors, and, when combined with WBRT of 30 Gy in 10 fractions, was associated with a high radiologic response rate.