Oxidized mC modulates synthetic lethality to PARP inhibitors for the treatment of leukemia

TET2 haploinsufficiency is a driving event in myeloid cancers and is associated with a worse prognosis in patients with acute myeloid leukemia (AML). Enhancing residual TET2 activity using vitamin C increases oxidized 5-methylcytosine (mC) formation and promotes active DNA demethylation via base excision repair (BER), which slows leukemia progression. We utilize genetic and compound library screening approaches to identify rational combination treatment strategies to improve use of vitamin C as an adjuvant therapy for AML. In addition to increasing the efficacy of several US Food and Drug Administration (FDA)-approved drugs, vitamin C treatment with poly-ADP-ribosyl polymerase inhibitors (PARPis) elicits a strong synergistic effect to block AML self-renewal in murine and human AML models. Vitamin-C-mediated TET activation combined with PARPis causes enrichment of chromatin-bound PARP1 at oxidized mCs and γH2AX accumulation during mid-S phase, leading to cell cycle stalling and differentiation. Given that most AML subtypes maintain residual TET2 expression, vitamin C could elicit broad efficacy as a PARPi therapeutic adjuvant.

Targeting Mitochondrial Structure Sensitizes Acute Myeloid Leukemia to Venetoclax Treatment

The BCL2 family plays important roles in acute myeloid leukemia (AML). Venetoclax, a selective BCL2 inhibitor, has received FDA approval for the treatment of AML. However, drug resistance ensues after prolonged treatment, highlighting the need for a greater understanding of the underlying mechanisms. Using a genome-wide CRISPR/Cas9 screen in human AML, we identified genes whose inactivation sensitizes AML blasts to venetoclax. Genes involved in mitochondrial organization and function were significantly depleted throughout our screen, including the mitochondrial chaperonin CLPB. We demonstrated that CLPB is upregulated in human AML, it is further induced upon acquisition of venetoclax resistance, and its ablation sensitizes AML to venetoclax. Mechanistically, CLPB maintains the mitochondrial cristae structure via its interaction with the cristae-shaping protein OPA1, whereas its loss promotes apoptosis by inducing cristae remodeling and mitochondrial stress responses. Overall, our data suggest that targeting mitochondrial architecture may provide a promising approach to circumvent venetoclax resistance. SIGNIFICANCE: A genome-wide CRISPR/Cas9 screen reveals genes involved in mitochondrial biological processes participate in the acquisition of venetoclax resistance. Loss of the mitochondrial protein CLPB leads to structural and functional defects of mitochondria, hence sensitizing AML cells to apoptosis. Targeting CLPB synergizes with venetoclax and the venetoclax/azacitidine combination in AML in a p53-independent manner.See related commentary by Savona and Rathmell, p. 831.This article is highlighted in the In This Issue feature, p. 813.

Abstract P1-13-11: Neratinib in the extended adjuvant treatment of patients from Asia with early-stage HER2+ breast cancer after trastuzumab-based therapy: Exploratory analyses from the phase III ExteNET trial

Background: Current breast cancer knowledge is based largely on studies conducted in western populations. Their findings may not be generalizable to Asian women because of ethnic, genetic and lifestyle differences. Neratinib (N) is an irreversible tyrosine kinase inhibitor of HER1, 2 and 4. The international, randomized, placebo (P)-controlled phase III ExteNET trial showed that 1 year (yr) of N after trastuzumab (T)-based adjuvant therapy significantly improved 2-yr invasive disease-free survival (iDFS) in patients (pts) with early-stage HER2+ breast cancer (HR 0.67; 95% CI 0.50–0.91; p=0.009) [Chan et al. Lancet Oncol 2016]. The significant iDFS benefit with N was shown to be durable after 5 yrs' follow-up (HR 0.73; 95% CI 0.57-0.92; p=0.008) [Martin et al. ESMO 2017]. We report efficacy and safety findings from pts enrolled from Asian centers (China, Hong Kong, Japan, Korea, Malaysia, Singapore, and Taiwan) on the ExteNET trial to better characterize the effects of N in Asian women.

Methods: Pts with early-stage HER2+ breast cancer were randomly assigned to oral N 240 mg/day or P for 1 yr after standard primary therapy and T-based adjuvant therapy. Antidiarrheal prophylaxis was not required by protocol. Data concerning disease recurrences were collected prospectively during yr 1-2 post-randomization, and from medical records during yr 3–5 post-randomization. Primary endpoint: iDFS. HR (95% CI) estimated using Cox proportional-hazards models stratified by nodal status, hormone-receptor status and prior T regimen. Data cut-off: 2-yr analysis, July 2014; 5-yr analysis, March 2017. Clinicaltrials.gov:NCT00878709.

Results: Of 2840 randomized pts (N, n=1420; P, n=1420), 341 (12%) were enrolled from Asian centers (N, n=165; P, n=176). Baseline characteristics: median age 53 yr; hormone receptor-positive 48%. Median treatment duration was similar in both groups (N, 351 days; P, 352 days). iDFS events in Asian vs ITT populations are shown in the Table.

 Primary 2-yr analysisa5-yr analysis NPNPAsian population, n165176165176iDFS events, n10151222HR (95% CI)b0.71 (0.31-1.57)0.54 (0.26-1.08)P-value (2-sided)0.4040.085ITT population, n1420142014201420iDFS events, n67106116163HR (95% CI)b0.66 (0.49-0.90)0.73 (0.57-0.92)P-value (2-sided)0.0080.008a. Primary study endpoint; b. Neratinib vs placebo

The incidence of grade 3/4 diarrhea with N was slightly higher in Asian pts (46.1% vs ITT, 39.8%). All other grade 3/4 adverse events with N were rare among Asian pts (elevated ALT, mucosal inflammation, 2 pts each; other events, 1 pt each). Compliance with N in Asian pts was also improved (71% vs ITT, 61%).

Conclusions: In Asian pts enrolled into ExteNET, compliance with N was better and the magnitude of N effect was similar or greater that that observed in the ITT population. Although N-related grade 3/4 diarrhea was more common in Asian pts than in the ITT population, all other grade 3/4 events were rare. Despite small pt numbers, our analyses suggest that the findings from ExteNET are applicable to Asian pts, and support the conclusion that N reduces disease recurrences in Asian pts with early-stage HER2+ breast cancer after T-based adjuvant therapy.

Citation Format: Iwata H, Masuda N, Kim S-B, Inoue K, Rai Y, Fujita T, Shen Z-Z, Chiu JW, Ohtani S, Takahashi M, Yamamoto N, Miyaki T, Sun Q, Yen-Shen L, Xu B, Yap YS, Bustam AZ, Lee JR, Zhang B, Bryce R, Chan A. Neratinib in the extended adjuvant treatment of patients from Asia with early-stage HER2+ breast cancer after trastuzumab-based therapy: Exploratory analyses from the phase III ExteNET trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-13-11.

Risk of death from cardiovascular disease following breast cancer in Southeast Asia: a prospective cohort study

Breast cancer incidence and survival is high in Southeast Asia. As such, many women diagnosed with breast cancer are at risk of dying of other causes. Given the increased risk of cardiotoxicity induced by breast cancer treatments, it is important to identify patients at high risk of cardiovascular disease (CVD) mortality. The aim of this study was to investigate if this risk varies by age and ethnicity. Patient details were obtained from 5,868 Chinese, Malay, and Indian women diagnosed with in situ or non-metastasized invasive breast cancer at the National University Hospital of Singapore and KK Women's and Children's Hospital in Singapore. Death causes were obtained from the National Registry of Births and Deaths. Flexible parametric survival models estimated CVD mortality rates and hazard ratios. During a median follow-up of six years, 1,010 deaths occurred of which 6.8% were due to CVD. CVD mortality rates of older women peaked within the first year following diagnosis and increased over time since diagnosis. Indian had more than double the risk of CVD mortality than Chinese, independent of age at diagnosis and stage. Taking ethnicity and age into account may promote CVD risk stratification and management in (Southeast Asian) women with breast cancer.

Abstract P4-22-16: First-line ribociclib + letrozole in patients with HR+, HER2– advanced breast cancer (ABC) presenting with visceral metastases or bone-only disease: A subgroup analysis of the MONALEESA-2 trial

Background: Patients with ABC who present with visceral metastases have a worse outcome than patients with non-visceral disease, while patients with bone-only disease tend to have a better prognosis. Ribociclib (LEE011) is an oral, selective inhibitor of cyclin-dependent kinase (CDK) 4/6. In a Phase 3, placebo-controlled, randomized trial (MONALEESA-2; NCT01958021), first-line ribociclib (R) + letrozole (L) significantly prolonged progression-free survival (PFS) vs placebo (P) + L in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) ABC, with a hazard ratio of 0.556 (95% confidence interval [CI]: 0.429–0.720; p=0.00000329) at the interim analysis cut-off date (Jan 29, 2016). Here, we present subgroup analyses in patients with visceral metastases, and those with bone-only disease.

Methods: Postmenopausal women with HR+, HER2– ABC were randomized 1:1 to receive R (600 mg/day; 3-weeks-on/1-week-off) + L (2.5 mg/day; continuous) or P+L, stratified by the presence of liver and/or lung metastases. No prior CDK4/6 inhibitors or systemic therapy for ABC were allowed. Eligible patients had Eastern Cooperative Oncology Group performance status ≤1, baseline alanine/aspartate aminotransferase levels <5× upper limit of normal (ULN) or <2.5× ULN for patients with or without liver metastases, respectively, and ≥1 predominantly lytic bone lesion at baseline for patients with bone-only disease. Locally assessed PFS was analyzed for all patients (primary endpoint), and for predefined patient subgroups.

Results: Overall, 668 patients were randomized; 393 had visceral metastases and 147 had bone-only disease.

 Visceral metastasesBone-only disease n=393n=147 R+LP+LR+LP+L n=197n=196n=69n=78Median age, years (range)63 (23–91)63 (29–88)65 (37–85)63 (37–84)De novo metastatic disease, n (%)53 (27)55 (28)28 (41)24 (31)Non-de novo disease-free interval, n (%)≤24 months12 (6)15 (8)5 (7)6 (8)>24 months132 (67)126 (64)36 (52)48 (62)Discontinued treatment, n (%)83 (42)111 (57)29 (42)40 (51)Reason for discontinuation, n (%)Disease progression56 (28)93 (47)17 (25)31 (40)Patient/physician decision10 (5)15 (8)7 (10)6 (8)Adverse events16 (8)3 (2)4 (6)2 (3)Protocol deviation001 (1)1 (1)Death1 (<1)000

In patients with visceral metastases: Median PFS was not reached in the R+L arm (95% CI: 19.3–not estimable [NE]) vs 13.0 months (95% CI: 12.6 –16.5) in the P+L arm, with hazard ratio 0.535 (95% CI: 0.385–0.742). Median duration of exposure was 12.0 and 13.0 months (R and L, respectively) in the R+L arm, and 12.1 and 12.2 months (P and L, respectively) in the P+L arm.

In patients with bone-only disease: Median PFS was not reached in the R+L arm (95% CI: NE–NE) vs 15.3 months (95% CI: 13.8–NE) in the P+L arm, with hazard ratio 0.690 (95% CI: 0.381–1.249). Median duration of exposure was 12.1 and 12.6 months (R and L, respectively) in the R+L arm, and 12.7 and 12.9 months (P and L, respectively) in the P+L arm.

Conclusions: First-line R+L was well tolerated and significantly prolonged PFS vs P+L in postmenopausal women with HR+, HER2– ABC, both in patients with visceral metastases and those with bone-only disease.

Keywords: Advanced breast cancer; CDK4/6 inhibitor; Letrozole; Ribociclib

Citation Format: Burris HA, Chan A, Campone M, Blackwell KL, Winer EP, Janni W, Verma S, Burdaeva O, Alba E, Favret AM, Mondal S, Miller M, Germa C, Hirawat S, Yap YS. First-line ribociclib + letrozole in patients with HR+, HER2– advanced breast cancer (ABC) presenting with visceral metastases or bone-only disease: A subgroup analysis of the MONALEESA-2 trial [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-16.

Abstract B2-45: Uncovering coordinated regulation of transcription factors by microRNAs using integrated network models

MicroRNAs (miRNAs) are small non-coding RNAs that play a significant role in development and cancer but induce only moderate repression of direct messenger RNA (mRNA) targets, suggesting that they coordinate with other modes of cellular regulation to affect cellular phenotype. In this work we exhaustively profile the transcriptional and post-transcriptional regulatory changes between an isogenic pair of murine fibroblast cell lines with and without Dicer, an enzyme required for miRNA processing. Through quantitative analysis of diverse high-throughput datasets collected from both cell lines, we were able to decouple transcriptional from post-transcriptional changes reflected in mRNA expression changes between cells with and without miRNAs.

We present three major findings. First, we find that direct miRNA-mRNA interactions have a limited impact on gene expression changes upon Dicer deletion when compared to changes at transcription. We then introduce an integrative graphical network approach to identify specific transcription factors that explain the observed changes in gene expression upon loss of Dicer. Validation of this computational model via transcription factor over-expression reveals a subset of the miRNA-mediated transcriptional program that is activated upon Dicer loss, confirming that transcriptional networks amplify the effects of miRNAs. Lastly, we use this network to examine coordination between transcriptional and post-transcriptional regulation. We identify numerous coherent and in-coherent feed-forward loops, network motifs that have been alluded to but only minimally studied in the context of microRNAs and transcription factors, and find that genes regulated within feed-forward loops by microRNAs and transcription factors exhibit distinct properties in development.

In summary, our work illustrates how transcriptional networks amplify the effects of microRNAs. We show coordinated regulation of transcription factors by microRNAs that suggests that most gene expression changes attributed to microRNAs in diseases such as cancer are due to changes in transcription rather than microRNA-mediated degradataion. As such, this work has the potential to reframe future studies of microRNAs in the context of cancer by shifting the focus to understanding the impact of microRNAs on transcription factors.

Citation Format: Sara JC Gosline, Allan M. Gurtan, Courtney K. JnBaptiste, Andrew Bosson, Pamela Milani, Simona Dalin, Bryan Matthews, Yoon Sing Yap, Phillip A. Sharp, Ernest Fraenkel. Uncovering coordinated regulation of transcription factors by microRNAs using integrated network models. [abstract]. In: Proceedings of the AACR Special Conference on Computational and Systems Biology of Cancer; Feb 8-11 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 2):Abstract nr B2-45.

Association of proinflammatory cytokines and chemotherapy-associated cognitive impairment in breast cancer patients: a multi-centered, prospective, cohort study

BACKGROUND

Existing evidence suggests that proinflammatory cytokines play an intermediary role in postchemotherapy cognitive impairment. This is one of the largest multicentered, cohort studies conducted in Singapore to evaluate the prevalence and proinflammatory biomarkers associated with cognitive impairment in breast cancer patients.

PATIENTS AND METHODS

Chemotherapy-receiving breast cancer patients (stages I-III) were recruited. Proinflammatory plasma cytokines concentrations [interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, interferon-γ and tumor necrosis factor-α] were evaluated at 3 time points (before chemotherapy, 6 and 12 weeks after chemotherapy initiation). The FACT-Cog (version 3) was utilized to evaluate patients' self-perceived cognitive disturbances and a computerized neuropsychological assessment (Headminder) was administered to evaluate patients' memory, attention, response speed and processing speed. Changes of cognition throughout chemotherapy treatment were compared against the baseline. Linear mixed-effects models were applied to test the relationships of clinical variables and cytokine concentrations on self-perceived cognitive disturbances and each objective cognitive domain.

RESULTS

Ninety-nine patients were included (age 50.5 ± 8.4 years; 81.8% Chinese; mean duration of education = 10.8 ± 3.3 years). Higher plasma IL-1β was associated with poorer response speed performance (estimate: -0.78; 95% confidence interval (CI) -1.34 to -0.03; P = 0.023), and a higher concentration of IL-4 was associated with better response speed performance (P = 0.022). Higher concentrations of IL-1β and IL-6 were associated with more severe self-perceived cognitive disturbances (P = 0.018 and 0.001, respectively). Patients with higher concentrations of IL-4 also reported less severe cognitive disturbances (P = 0.022).

CONCLUSIONS

While elevated concentrations of IL-6 and IL-1β were observed in patients with poorer response speed performance and perceived cognitive disturbances, IL-4 may be protective against chemotherapy-associated cognitive impairment. This study is important because cytokines would potentially be mechanistic mediators of chemotherapy-associated cognitive changes.

TET1 is a tumor suppressor of hematopoietic malignancy

The methylcytosine dioxygenase TET1 ('ten-eleven translocation 1') is an important regulator of 5-hydroxymethylcytosine (5hmC) in embryonic stem cells. The diminished expression of TET proteins and loss of 5hmC in many tumors suggests a critical role for the maintenance of this epigenetic modification. Here we found that deletion of Tet1 promoted the development of B cell lymphoma in mice. TET1 was required for maintenance of the normal abundance and distribution of 5hmC, which prevented hypermethylation of DNA, and for regulation of the B cell lineage and of genes encoding molecules involved in chromosome maintenance and DNA repair. Whole-exome sequencing of TET1-deficient tumors revealed mutations frequently found in non-Hodgkin B cell lymphoma (B-NHL), in which TET1 was hypermethylated and transcriptionally silenced. Our findings provide in vivo evidence of a function for TET1 as a tumor suppressor of hematopoietic malignancy.

Tamoxifen metabolism predicts drug concentrations and outcome in premenopausal patients with early breast cancer

Tamoxifen is the standard-of-care treatment for estrogen receptor-positive premenopausal breast cancer. We examined tamoxifen metabolism via blood metabolite concentrations and germline variations of CYP3A5, CYP2C9, CYP2C19 and CYP2D6 in 587 premenopausal patients (Asians, Middle Eastern Arabs, Caucasian-UK; median age 39 years) and clinical outcome in 306 patients. N-desmethyltamoxifen (DM-Tam)/(Z)-endoxifen and CYP2D6 phenotype significantly correlated across ethnicities (R(2): 53%, P<10(-77)). CYP2C19 and CYP2C9 correlated with norendoxifen and (Z)-4-hydroxytamoxifen concentrations, respectively (P<0.001). DM-Tam was influenced by body mass index (P<0.001). Improved distant relapse-free survival (DRFS) was associated with decreasing DM-Tam/(Z)-endoxifen (P=0.036) and increasing CYP2D6 activity score (hazard ratio (HR)=0.62; 95% confidence interval (CI), 0.43-0.91; P=0.013). Low (<14 nM) compared with high (>35 nM) endoxifen concentrations were associated with shorter DRFS (univariate P=0.03; multivariate HR=1.94; 95% CI, 1.04-4.14; P=0.064). Our data indicate that endoxifen formation in premenopausal women depends on CYP2D6 irrespective of ethnicity. Low endoxifen concentration/formation and decreased CYP2D6 activity predict shorter DRFS.

Abstract P4-12-28: HER2-related biomarkers in HER2+ breast cancer patients in Asia Pacific

Recent findings suggest that HER2-related molecular markers such as PTEN deletion or downregulation, PIK3CA mutation, truncated HER2 receptor (p95HER2), and tumor HER2 mRNA levels, have the potential to predict anti-HER2 treatment response. We evaluated the distribution of these biomarkers at the time of primary diagnosis and their relationship to responsiveness to lapatinib treatment in the metastatic setting in HER2+ breast cancer patients.

We conducted an observational study of female HER2+ breast cancer patients who were initiated on lapatinib treatment following recurrence or metastases in five Asia Pacific countries. Patients were enrolled between August 2010 and December 2012. Eligible patients had a tumor biopsy specimen available from their primary breast cancer diagnosis or before they started on any anti-HER2 treatment, had not been exposed to more than two lines of anti-HER2 treatment in the metastatic setting or other experimental anti-HER2 treatment, and had no other primary tumor. Biomarkers levels at primary diagnosis were measured; PTEN levels were assessed by immunohistochemistry and PIK3CA mutations were detected by a mass spectroscopy-based approach. The primary endpoint was progression-free survival (PFS) from the initiation of first lapatinib-based regimen given in metastatic setting to disease progression from that regimen or death from any cause. PFS analysis was conducted with a data cut-off date of 31 December 2012.

A total of 162 patients were included in this study and 96% have confirmed HER2+ breast cancer primary tumor. The mean age was 52±10 years and 97% had metastases at study entry, with bone being the most common site of metastasis (48%). About a quarter had PTEN protein loss (24%), 30% had PIK3CA mutation, and 7% had both at primary diagnosis. No significant association was observed between both biomarkers or between each biomarker and estrogen receptor status or HER2 status.

Table 1. Relationship between PTEN and PIK3CA PIK3CA mutation, n (%)PIK3CA wild-type, n (%)p-valuePTEN status  0.674Loss11 (29)27 (71) Normal33 (33)68 (67) 

Patients with altered PTEN expression, or PIK3CA mutation showed comparable PFS with lapatinib-based treatment as those with normal PTEN or PIK3CA expression at analysis cut-off date (median PFS 7.5 and 8.5 months respectively vs. 8.9 and 9.0 months respectively; p = 0.502 and p = 0.268 respectively). There remained no significant difference in PFS after having adjusted for significant confounders (HR 1.2 and 1.1 respectively; 95% CI 0.7–1.9 and 0.7–1.8 respectively; p = 0.481 and p = 0.730 respectively). The distribution of p95HER2 expression and tumor HER mRNA levels and their association with PFS will be included at the time of presentation.

Our preliminary findings suggest that PTEN alteration, or PIK3CA mutation may not be predictive of clinical response to lapatinib treatment in HER2+ breast cancer patients. The final PFS results with additional markers will provide more clues regarding their relationship to treatment response.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-12-28.

Analysis of in vitro insulin-resistance models and their physiological relevance to in vivo diet-induced adipose insulin resistance

Diet-induced obesity (DIO) predisposes individuals to insulin resistance, and adipose tissue has a major role in the disease. Insulin resistance can be induced in cultured adipocytes by a variety of treatments, but what aspects of the in vivo responses are captured by these models remains unknown. We use global RNA sequencing to investigate changes induced by TNF-α, hypoxia, dexamethasone, high insulin, and a combination of TNF-α and hypoxia, comparing the results to the changes in white adipose tissue from DIO mice. We found that different in vitro models capture distinct features of DIO adipose insulin resistance, and a combined treatment of TNF-α and hypoxia is most able to mimic the in vivo changes. Using genome-wide DNase I hypersensitivity followed by sequencing, we further examined the transcriptional regulation of TNF-α-induced insulin resistance, and we found that C/EPBβ is a potential key regulator of adipose insulin resistance.

Brain metastases in Asian HER2-positive breast cancer patients: anti-HER2 treatments and their impact on survival

BACKGROUND

In Asia, large-scale studies on anti-HER2 treatment in HER2-positive breast cancer patients with brain metastases are limited. We studied the treatment patterns of these patients in Asia to evaluate the impact of anti-HER2 treatment on the time to occurrence of brain metastases (TTBM) and survival after brain metastasis (BM).

METHODS

A retrospective study of HER2-positive breast cancer patients diagnosed with BM between January 2006 and December 2008 in six Asian countries was conducted. Demographics, tumour characteristics, treatment details, and events dates were collected from medical records.

RESULTS

Data from 280 patients were analysed. Before BM, 63% received anti-HER2 treatment. These patients had significantly longer TTBM than those without anti-HER2 treatment (median 33 vs 19 months; P<0.002). After BM, 93% received radiotherapy, 57% received chemotherapy, and 41% received anti-HER2 treatment (trastuzumab and/or lapatinib). Use of both anti-HER2 agents, primarily sequentially, after BM demonstrated the longest survival after BM and was associated with a significant survival benefit over no anti-HER2 treatment (median 26 vs 6 months; hazard ratio 0.37; 95% CI 0.19-0.72).

CONCLUSION

Anti-HER2 treatment before BM was associated with longer TTBM. Anti-HER2 treatment after BM was associated with a survival benefit, especially when both trastuzumab and lapatinib were utilised.

Clinical efficacy of capecitabine as first-line chemotherapy in metastatic breast cancer--how low can you go?

Sixty-three patients received capecitabine at 1000 mg/m2 twice daily every 2 out of 3 weeks as first-line treatment for advanced disease at our institution. Forty-five patients (71%) had previously received adjuvant or neoadjuvant chemotherapy. The median number of capecitabine cycles administered was 5(1-40). Forty-eight patients had measurable disease with response rate (RR) of 29%. The median time to progression (TTP) was 18(2-122) weeks. Seven patients (11%) had TTP of >1 yr, four of whom received more than 10(24-40) cycles of capecitabine. Thirty-seven percent of patients still needed dose reductions. Our retrospective audit is consistent with a previously published study which used a higher starting dose of capecitabine as first-line chemotherapy. For a subgroup of patients, capecitabine can result in a long TTP with minimal toxicity. The benefit of continuing capecitabine beyond a fixed number of cycles should be investigated further. Schedules using even lower doses of capecitabine for longer periods may also be of interest.

Right ventricular function and exercise performance late after primary repair of tetralogy of Fallot with the transannular patch in infancy

To evaluate the late effects of chronic pulmonary regurgitation against the putative benefits from the current surgical trend of primary repair of tetralogy of Fallot with a transannular patch in infancy, 10 patients > 10 years after early primary repair and 7 matched normal controls underwent exercise stress test and cine magnetic resonance imaging assessment of ventricular functions. Right ventricular impaired diastolic function and decreased exercise capacity, both significantly associated with pulmonary regurgitation in patients, indicated that early primary repair of tetralogy may not prevent late ventricular dysfunction and diminished exercise performance if chronic regurgitation results from right ventricular outflow tract reconstruction.