Human epidermal growth factor receptor 2-positive (HER2+) breast cancer accounts for ∼20% of invasive breast cancers and is associated with poor prognostics. The recent outcome of HER2+ breast cancer treatment has been vastly improved owing to the application of antibody-targeted therapies. Trastuzumab (Herceptin) is a monoclonal antibody designed to target HER2+ breast cancer cells. In addition to improved survival in the adjuvant treatment of HER2+ breast cancer, trastuzumab treatment has also been associated with cardiotoxicity side effect. However, the molecular mechanisms of trastuzumab action and trastuzumab-mediated cardiotoxicity are still not fully understood. Previous research utilized bulk transcriptomics analysis to study the underlining mechanisms, which relied on averaging molecular signals from bulk tumor samples and might have overlooked key expression features within breast cancer tumor. In contrast to previous research, we compared the single cancer cell level transcriptome profile between trastuzumab-treated and nontreated patients to reveal a more in-depth transcriptome profile. A total of 461 significantly differential expressed genes were identified, including previously defined and novel gene expression signatures. In addition, we found that trastuzumab-enhanced MGP gene expression could be used as prognostics marker for longer patient survival in breast invasive carcinoma patients, and validated our finding using TCGA (The Cancer Genome Atlas) breast cancer dataset. Moreover, our study revealed a 48-gene expression signature that is associated with cell death of cardiomyocytes, which could be used as early biomarkers for trastuzumab-mediated cardiotoxicity. This work is the first study to look at single cell level transcriptome profile of trastuzumab-treated patients, providing a new understanding of the molecular mechanism(s) of trastuzumab action and trastuzumab-induced cardiotoxicity side effects.

We describe a case of a patient treated for cognitive dysfunction (CD) with suspected thiamine deficiency (TD). A 74-year-old man with gastric cancer presented with grade 3 diarrhea and grade 1 anorexia. He had been receiving trastuzumab plus tegafur (a chemotherapeutic fluorouracil prodrug), gimeracil, and oteracil (S-1) and oxaliplatin. On admission, cognitive function was assessed with the Hasegawa's Dementia Scale (HDS-R) because he had impaired short-term memory. His thiamine levels increased from 22 to 109 ng/mL after administration of 75 mg of thiamine. Furthermore, the patient's HDS-R score improved from 9 to 22, and cognitive and memory functions improved. TD should be considered in older CD patients receiving oral chemotherapy agents including fluorouracil.

INTRODUCTION: Despite improvements in the management of HER2+ breast cancer, metastatic disease is still fatal. Usually, these patients receive several lines of chemotherapy associated with HER2 targeted treatments. Most of the trials using innovative approaches are positioning themselves in disease that is resistant to pertuzumab and trastuzumab emtansine (TDM1).
AREAS COVERED: We describe the recent advances in clinical development of anti-HER2 treatments. To this aim, we used literature search via Pubmed and made an inventory of abstracts published during the last two years in major oncology conferences.
EXPERT OPINION: Further changes will probably occur during the next decade in the management of metastatic HER2-positive breast cancer. This is mainly driven by the fact that the two mainstay drugs (pertuzumab and TDM-1) that confer prolonged survival (56 months) to these patients are currently being used in the treatment of early-stage disease in a subset of patients. Thus, there is an urgent need to develop new, innovative approaches in those patients whose disease has become resistant to these highly potent drugs. Several new antibody-drug conjugates, bispecific antibodies or new generation tyrosine kinase inhibitor (TKIs) hold promise and should be assessed and compared with drugs currently used.

BACKGROUND: In 2013, the interim analysis of the Protocol for Herceptin as Adjuvant therapy with Reduced Exposure (PHARE) trial could not show that 6 months of adjuvant trastuzumab was non-inferior to 12 months. Here, we report the planned final analysis based on the prespecified number of occurring events.
METHODS: PHARE is an open-label, phase 3, non-inferiority randomised trial of patients with HER2-positive early breast cancer comparing 6 months versus 12 months of trastuzumab treatment concomitant with or following standard neoadjuvant or adjuvant chemotherapy. The study was undertaken in 156 centres in France. Eligible patients were women aged 18 years or older with non-metastatic, operable, histologically confirmed adenocarcinoma of the breast and either positive axillary nodes or negative axillary nodes but a tumour of at least 10 mm. Participants must have received at least four cycles of a chemotherapy for this breast cancer and have started receiving adjuvant trastuzumab-treatment. Eligible patients were randomly assigned to either 6 months or 12 months of trastuzumab therapy duration between the third and sixth months of adjuvant trastuzumab. The randomisation was stratified by concomitant or sequential treatment with chemotherapy, oestrogen receptor status, and centre. The primary objective was non-inferiority in the intention-to-treat population in the 6-month group in terms of disease-free survival with a prespecified hazard margin of 1·15. This trial is registered with ClinicalTrials.gov, number NCT00381901.
FINDINGS: 3384 patients were enrolled and randomly assigned to either 12 months (n=1691) or 6 months (n=1693) of adjuvant trastuzumab. One patient in the 12-month group and three patients in the 6-month group were excluded, so 1690 patients in each group were included in the intention-to-treat analysis. At a median follow-up of 7·5 years (IQR 5·3-8·8), 704 events relevant to disease-free survival were observed (345 [20·4%] in the 12-month group and 359 [21·2%] in the 6-month group). The adjusted hazard ratio for disease-free survival in the 12-month group versus the 6-month group was 1·08 (95% CI 0·93-1·25; p=0·39). The non-inferiority margin was included in the 95% CI. No differences in effects pertaining to trastuzumab duration were found in any of the subgroups. After the completion of trastuzumab treatment, rare adverse events occurred over time and the safety analysis remained similar to the previously published report. In particular, we found no change in the cardiac safety comparison, and only three additional cases in which the left ventricular ejection fraction decreased to less than 50% have been reported in the 12-month group.
INTERPRETATION: The PHARE study did not show the non-inferiority of 6 months versus 12 months of adjuvant trastuzumab. Hence, adjuvant trastuzumab standard duration should remain 12 months.
FUNDING: The French National Cancer Institute.

BACKGROUND: Adjuvant trastuzumab significantly improves outcomes for patients with HER2-positive early breast cancer. The standard treatment duration is 12 months but shorter treatment could provide similar efficacy while reducing toxicities and cost. We aimed to investigate whether 6-month adjuvant trastuzumab treatment is non-inferior to the standard 12-month treatment regarding disease-free survival.
METHODS: This study is an open-label, randomised phase 3 non-inferiority trial. Patients were recruited from 152 centres in the UK. We randomly assigned patients with HER2-positive early breast cancer, aged 18 years or older, and with a clear indication for chemotherapy, by a computerised minimisation process (1:1), to receive either 6-month or 12-month trastuzumab delivered every 3 weeks intravenously (loading dose of 8 mg/kg followed by maintenance doses of 6 mg/kg) or subcutaneously (600 mg), given in combination with chemotherapy (concurrently or sequentially). The primary endpoint was disease-free survival, analysed by intention to treat, with a non-inferiority margin of 3% for 4-year disease-free survival. Safety was analysed in all patients who received trastuzumab. This trial is registered with EudraCT (number 2006-007018-39), ISRCTN (number 52968807), and ClinicalTrials.gov (number NCT00712140).
FINDINGS: Between Oct 4, 2007, and July 31, 2015, 2045 patients were assigned to 12-month trastuzumab treatment and 2044 to 6-month treatment (one patient was excluded because they were double randomised). Median follow-up was 5·4 years (IQR 3·6-6·7) for both treatment groups, during which a disease-free survival event occurred in 265 (13%) of 2043 patients in the 6-month group and 247 (12%) of 2045 patients in the 12-month group. 4-year disease-free survival was 89·4% (95% CI 87·9-90·7) in the 6-month group and 89·8% (88·3-91·1) in the 12-month group (hazard ratio 1·07 [90% CI 0·93-1·24], non-inferiority p=0·011), showing non-inferiority of the 6-month treatment. 6-month trastuzumab treatment resulted in fewer patients reporting severe adverse events (373 [19%] of 1939 patients vs 459 [24%] of 1894 patients, p=0·0002) or stopping early because of cardiotoxicity (61 [3%] of 1939 patients vs 146 [8%] of 1894 patients, p<0·0001).
INTERPRETATION: We have shown that 6-month trastuzumab treatment is non-inferior to 12-month treatment in patients with HER2-positive early breast cancer, with less cardiotoxicity and fewer severe adverse events. These results support consideration of reduced duration trastuzumab for women at similar risk of recurrence as to those included in the trial.
FUNDING: UK National Institute for Health Research, Health Technology Assessment Programme.

Trastuzumab is integral to HER2+ cancer treatment, but its therapeutic index is narrowed by the development of resistance. Phosphorylation of the translation initiation factor eIF2α (eIF2α-P) is the nodal point of the integrated stress response, which promotes survival or death in a context-dependent manner. Here, we show an anti-tumor function of the protein kinase PKR and its substrate eIF2α in a mouse HER2+ breast cancer model. The anti-tumor function depends on the transcription factor ATF4, which upregulates the CDK inhibitor P21

OBJECTIVES: To systematically review and assess the quality of the economic evidence of adjuvant trastuzumab usage in early breast cancer in Asian countries.
METHODS: Literature search was performed using 6 electronic databases (PubMed, Scopus, Ovid MEDLINE, EconLit, National Health Service Economic Evaluation Database, and ISI Web of Knowledge). The final search was performed in October 2018. All potential economic studies were then checked for eligibility. The reporting and methodological qualities of each study were independently assessed by 2 authors of this review, using the Consolidated Health Economic Evaluation Reporting Standards, Drummond, and Philips checklists. To compare the different currencies used in these studies, all costs were converted into US dollars (2016).
RESULTS: A total of 6 studies were included; most of them were performed from the healthcare provider perspective. The incremental cost-effectiveness ratio for evaluation performed for a lifetime horizon were reported at $8573 and $20 816 per quality-adjusted life-year in 2 studies. The model outcome was generally sensitive to the changes in trastuzumab drug acquisition cost and discount rate, as well as its clinical effectiveness. For the quality assessment, all studies fulfilled more than 50% of the requirements in the Consolidated Health Economic Evaluation Reporting Standards, Drummond, and Philips checklists.
CONCLUSIONS: Adjuvant trastuzumab therapy is considered a cost-effective option for early breast cancer in Asian countries including China, Iran, Japan, Singapore, and Taiwan. All studies were generally well conducted. Economic evaluations from the societal perspective, with inclusion of indirect and informal care costs, are warranted to facilitate informed decision making among policy makers.

The effects of standard clinical therapies including surgery and chemotherapy are poor in advanced gallbladder cancer (GBC). There are a few reported cases of human epidermal growth factor receptor 2 (HER2)-positive GBC that responded well to trastuzumab. But trastuzumab has not yet been used to treat HER2-negative GBC. In this study, we investigated the cytotoxic effects of different combined therapies with trastuzumab and gemcitabine and/or 5-fluorouracil on HER2-negative GBC cell lines in vitro and in vivo. Trastuzumab alone showed almost no cytotoxicity to GBC cells with originally low HER2 gene amplification. Sequential therapy with chemotherapy followed by trastuzumab showed superiority over reverse sequential chemotherapy (

BACKGROUND: Over the last 10 years, there has been a major treatment revolution for early human epidermal growth factor receptor 2 (HER2)-positive breast cancer. We aimed to explore the outcome of different neoadjuvant chemotherapy in a tertiary breast cancer centre with early HER2-positive breast cancer as well as factors associated with pathological complete response (pCR) and recurrence-free survival (RFS). The pattern of recurrence was also studied.
METHODS: This retrospective study analysed the outcome of neoadjuvant chemotherapy during the period 2005 to 2016 in a tertiary referral centre in Hong Kong. Patients were divided into three groups according to the neoadjuvant chemotherapy they received: chemotherapy only (Chemo), chemotherapy plus trastuzumab (Chemo-H) and chemotherapy plus double anti-HER2 therapy (Chemo-DH).
RESULTS: There were 226 cases analysed during the study period. The rate of pCR was 5%, 26% and 60% in Chemo, Chemo-H and Chemo-DH groups, respectively (Chemo vs pooled Chemo-H/DH: p<0.0001; Chemo-H vs Chemo-DH: p<0.0001). This was accompanied by a trend of increased rate of breast conservation therapy in Chemo-DH cohort (p=0.046). Use of double anti-HER2 therapy, older age (>50 years) and hormone receptor negativity were associated with more pCR. pCR was associated with better RFS. Among those with recurrence, the proportion of patients with brain as the only site of recurrence increased remarkably with more efficacious anti-HER2 treatment (0% in Chemo, 8% in Chemo-H, 67% in Chemo-DH).
CONCLUSION: pCR remains an important predictive factor for improved RFS. In the era of dual anti-HER2 neoadjuvant therapy, brain-only recurrence poses a challenge to disease surveillance and treatment.

OBJECTIVE: The APHINITY trial assessed the effectiveness and the safety of adding pertuzumab to trastuzumab and chemotherapy (THP) compared to trastuzumab and chemotherapy (TH) in the adjuvant management of human epidermal growth factor 2-positive (HER2+) breast cancer. We performed a study to project the potential cost-effectiveness of THP vs. TH.
STUDY DESIGN: Trial-based cost-utility modeling analysis.
METHODS: We performed an economic evaluation from a payer perspective using a Markov model with six health states: invasive disease-free survival, non-metastatic recurrence, remission, first-line metastatic, subsequent line metastatic, and death. We parameterized the model using data from both arms in APHINITY extrapolated to a patient's lifetime horizon. Estimates of health state utilities were based on EQ-5D trial data and the literature, and costs were estimated from government sources and the published literature. The primary outcomes of the model were life-years (LYs), quality-adjusted LYs (QALYs), costs, and incremental cost-effectiveness ratios (ICERs). Uncertainty was addressed via univariate and probabilistic sensitivity analyses.
RESULTS: For the intention-to-treat population, the model projected improved outcomes (by 0.50 LYs and 0.45 QALYs) and increased costs (by $74 420) for ICERs of $147 774/LY gained and $167 185/QALY gained for PHT vs. HT patients. In the node-positive patient population, the model projected improved outcomes (by 0.86 LYs and 0.76 QALYs) and increased costs (by $66 647) for ICERs of $77 684/LY gained and $87 929/QALY gained. For the hormone-receptor-negative patient population, the model projected health gains, increased costs, and ICERs of $147 022/LY gained and $166 518/QALY gained. The results were sensitive to changes in the model time horizon.
CONCLUSION: The addition of pertuzumab to the available regimens for HER2+ early breast cancer is likely to be cost-effective for patients in the U.S. at high risk of recurrence.

Gastric cancer (GC) is one of the most common cancers worldwide. In the clinical setting, the identification of HER2 overexpression in GC was a significant finding, as trastuzumab, an anti-HER2 drug, provides a survival advantage to HER2-positive GC patients. In HER2-postive GC, the dysregulation of PI3K/AKT and MAPK/ERK signaling pathways has been reported, and inhibition of these pathways is an important therapeutic strategy. MiR-143 is known to act as a tumor suppressor in several cancers, such as bladder cancer, breast cancer, colorectal cancer, and gastric cancer. In the current study, we developed a novel chemically-modified miR-143 and explored the functions of this synthetic miR-143 (syn-miR-143) in HER2-positive gastric cancer. The expression level of miR-143 was down-regulated in GC cell lines, including HER2-positive GC cell lines, MKN7, and KATO-III. The ectopic expression of miR-143 in those cell lines suppressed cell growth through systemic silencing of KRAS and its effector signaling molecules, AKT and ERK. Furthermore, syn-miR-143 indirectly down-regulated the expression of HER2, an upstream molecule of KRAS, through silencing DEAD/H-box RNA helicase 6 (DDX6), RNA helicase, which enhanced HER2 protein expression at the translational step in HER2-positive GC cells. These findings suggested that syn-miR-143 acted as a tumor suppressor through the impairment of KRAS networks including the DDX6.

AIM: This study was conducted in order to evaluate the efficacy and safety of nanoparticle albumin-bound paclitaxel (nab-paclitaxel) plus trastuzumab followed by 5-fluorouracil/ epirubicin/cyclophosphamide (FEC) in a neoadjuvant chemotherapy (NAC) setting for patients with human epidermal growth factor receptor 2 (HER2)-positive operable breast cancer.
PATIENTS AND METHODS: Each patient received four cycles of 260 mg/m
RESULTS: Twenty-nine patients were analyzed for the efficacy and safety of this treatment. All patients completed four cycles of nab-paclitaxel and trastuzumab, and 28 patients completed four cycles of FEC. Twenty-seven patients subsequently underwent surgery. The pCR rate was 74.0%. The most frequent toxicity was sensory neuropathy (96.6%), but grade 3 neuropathy rate was 3.4%.
CONCLUSION: Nab-paclitaxel plus trastuzumab followed by FEC in patients with HER2-positive operable breast cancer is considerably effective and well tolerated.

Physical activity is known to prevent the occurrence of cancer and decrease the risk of breast cancer. At diagnosis of breast cancer, fewer than half of the patients reach the international recommendation for physical activity. However, breast cancer patients, and particularly HER2+ breast cancer patients, are exposed to treatment-induced cardiotoxicity because of a side effect of 2 molecules used in standard therapy to treat these tumors, i.e., anthracycline and trastuzumab. Cardiotoxicity can sometimes lead to discontinuation of the treatment and even to the development of cardiovascular diseases. Exercise is known to protect the cardiovascular system in the healthy population. Consequently, being physically active during treatment appears to be a way to prevent the negative impact of cancer treatment on the heart in this population. In particular, aerobic exercising could have a protective effect against treatment-induced cardiotoxicity. A supervised physical activity program seems to be the best way for breast cancer patients to be active during treatment. However, there is very little information, and in particular a lack of guidelines, on exercising available to patients. The interventional trials that have been conducted on this topic are very heterogeneous and no standard recommendations have been made available for cancer patients thus far. An effective physical activity program needs to take each patient's barriers and motivations into account in order to encourage the practice of physical activity throughout treatment. To ensure the success of the program, it is essential to facilitate adherence and especially maintain motivation. Further studies are needed to determine what practice guidelines oncologists should give their patients.

RATIONALE: Glucose 6-phosphate dehydrogenase (G6PD) deficiency is the most common enzymatic disorder of red blood cells that cause hemolytic anemia. Some anticancer drugs are reported to trigger oxidative stress; however, events of hemolysis are rarely discussed in patients with G6PD deficiency required oncologic treatments.
PATIENT CONCERNS: Here we reported a young woman with G6PD deficiency safely undergoing breast cancer treatment.
DIAGNOSIS: A 29-year-old patient was diagnosed with advanced cancer of the right breast with tumors positive for hormone receptor and human epidermal growth factor receptor 2.
INTERVENTIONS: The patient received chemotherapy with doxorubicin, cyclophosphamide, and docetaxel. During the administration of docetaxel, trastuzumab was concurrently administered and was continued after the completion of docetaxel. The patient underwent adjuvant radiotherapy; meanwhile, tamoxifen was administered as adjuvant endocrine treatment.
OUTCOMES: The treatment process was smooth. There was no evidence of hemolytic anemia. Except for hot flushes, the patient lives without remarkable side effects from ongoing or previous treatments.
LESSONS: Some patients have both G6PD deficiency and malignancy in a geographic area with relatively high incidence of the enzymatic disorder and certain types of cancer. We suggest that our report can contribute to the concern regarding the safety of patients with G6PD deficiency undergoing cancer treatment.

BACKGROUND Trastuzumab therapy is important for patients with HER2-positive breast cancer, but more and more patients have experienced trastuzumab resistance during recent years. Accumulating evidence from recent studies showed that long non-coding RNAs (lncRNAs) play essential roles in chemoresistance of various cancer types, but the precise role of lncRNAs in trastuzumab resistance is unclear. In the present study, we aimed to identify the biofunction of lncRNA APAP2-AS1 in tranastuzumab resistance and to reveal the underlying regulatory mechanism. MATERIAL AND METHODS By culturing HER2-positive SKBR-3 and BT474 cells with transtuzumab-containing medium, we built trastuzumab-resistant cells. Quantitative real-time PCR was used to test the expression of AGAP2-AS1 in the built trastuzumab-resistant cells. Cell viability assay and TUNEL assay were used to test the cell viability and apoptosis in each group. Exosomes were purified from cells cultured in exosomes-depleted FBS and identified by transmission electron microscopy. RESULTS qRT-PCR assay suggested that AGAP2-AS1 was upregulated in the built trastuzumab-resistant cells when compared with parental sensitive cells. Cell viability assay showed that silencing of AGAP2-AS1 enhanced the cytotoxicity induced by trastuzumab treatment. Mechanistically, we revealed that AGAP2-AS1 was secreted outside cells by incorporation into exosomes in an hnRNPA2B1-dependent manner. More importantly, co-culture AGAP2-AS1-containing exosomes with sensitive cells reduced the trastuzumab-induced cell death, and silencing of AGAP2-AS1 from exosomes reversed this effect. In summary, AGAP2-AS1 promotes trastuzumab resistance of breast cancer cells through packaging into exosomes. CONCLUSIONS Knockdown of AGAP2-AS1 may be helpful for improving the clinical outcome for HER2+ breast cancer patients and could serve as a therapeutic target.

This study aimed to evaluate the clinical efficacy of trastuzumab combined with lapatinib in the treatment of human epidermal growth factor receptor 2 (HER2) positive breast cancer. One hundred and fifty-four patients with breast cancer were randomly divided into a trastuzumab group (group A, 52 cases), a lapatinib group (group B, 48 cases) and a combination group (group C, 54 cases).

BACKGROUND: In treating human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer, the efficacy of capecitabine combined with HER2-directed agents such as trastuzumab and lapatinib is supported by some evidence. The combination of T-DM1 and S-1, another oral 5-FU, may be a safe alternative treatment for metastatic breast cancer.
OBJECTIVES: The optimal dose of S-1 was evaluated in combination with T-DM1 for patients with HER2-positive advanced or metastatic breast cancer. The safety and clinical response of this combination treatment were also assessed.
METHODS: This 3 + 3 dose-escalation study of S-1 given for the first 2 of 3 weeks, in combination with T-DM1 (3.6 mg/kg given every 3 weeks) to patients with trastuzumab-pretreated HER2-positive advanced or metastatic breast cancer was designed to evaluate the dose-limiting toxicity (DLT) occurrence in the first cycle. We also evaluated the safety and clinical activity of this combination treatment in multiple cycles. Two different dose levels of S-1 (65 and 80 mg/m2/day) were planned, although the capecitabine arm was abandoned because of slow recruitment.
RESULTS: Twelve out of the 13 patients enrolled were evaluable for DLT. One DLT (grade ≥3 non-hematological adverse events) occurred at dose level 0, leading to the expansion of this cohort to 6 patients, with an additional DLT (≥7 days discontinuation of medication), while no DLT occurred at dose level 1. As a result, the maximum tolerable dose of S-1 was determined to be 80 mg/m2/day for 14 days with T-DM1 3.6 mg/kg, repeated every 3 weeks. Two patients had grade 3 thrombocytopenia at dose level 0, and 1 patient at dose level 1.
CONCLUSIONS: S-1 can be safely combined with the clinically relevant dose of T-DM1 in patients with HER2-positive advanced or metastatic breast cancer. Further evaluation with a larger sample size is required for efficacy assessment.

BACKGROUND: Neratinib is an irreversible pan-HER tyrosine kinase inhibitor that inhibits PI3K/Akt and MAPK signaling pathways after HER2 receptor activation. The ExteNET study showed that neratinib significantly improved 5-year invasive disease-free survival (iDFS) in women who completed trastuzumab-based adjuvant therapy for early breast cancer (EBC). We assessed the prognostic and predictive significance of PIK3CA alterations in patients in ExteNET.
METHODS: Participants were women aged ≥ 18 years (≥ 20 years in Japan) with stage 1-3c (modified to stage 2-3c in February 2010) operable breast cancer, who had completed (neo)adjuvant chemotherapy plus trastuzumab ≤ 2 years before randomization, with no evidence of disease recurrence or metastatic disease at study entry. Patients were randomized to oral neratinib 240 mg/day or placebo for 1 year. Formalin-fixed, paraffin-embedded primary tumor specimens underwent polymerase chain reaction (PCR) PIK3CA testing for two hotspot mutations in exon 9, one hot-spot mutation in exon 20, and fluorescence in situ hybridization (FISH) analysis for PIK3CA amplification. The primary endpoint (iDFS) was tested with log-rank test and hazard ratios (HRs) estimated using Cox proportional-hazards models.
RESULTS: Among the intent-to-treat population (n = 2840), tumor specimens were available for PCR testing (991 patients) and PIK3CA FISH (702 patients). Overall, 262 samples were PIK3CA altered: 201 were mutated (77%), 52 (20%) were amplified, and 9 (3%) were mutated and amplified. iDFS was non-significantly worse in placebo-treated patients with altered vs wild-type PIK3CA (HR 1.34; 95% CI 0.72-2.50; P = 0.357). Neratinib's effect over placebo was significant in patients with PIK3CA-altered tumors (HR 0.41; 95% CI 0.17-0.90, P = 0.028) but not PIK3CA wild-type tumors (HR 0.72; 95% CI 0.36-1.41; P = 0.34). The interaction test was non-significant (P = 0.309).
CONCLUSIONS: Although there was a greater absolute risk reduction associated with neratinib treatment of patients with PIK3CA-altered tumors in ExteNET, current data do not support PIK3CA alteration as a predictive biomarker of response to neratinib in HER2-positive EBC.
TRIAL REGISTRATION: ClinicalTrials.gov , NCT00878709 . Trial registered April 9, 2009.

BACKGROUND: One year of adjuvant trastuzumab treatment is the standard of care for early stage human epidermal growth factor receptor 2 (HER2)-positive breast cancer patients; however, controversy remains regarding the optimal schedule of trastuzumab because the selection of the 1-year schedule was arbitrary. After the remarkable results of the PERSEPHONE trial as well as the updated final results of the PHARE trial, we performed an updated meta-analysis to reassess the efficacy and safety of shorter durations of trastuzumab.
METHODS: A literature search of databases was conducted to identify randomized controlled trials reporting the efficacy and cardiotoxicity of shorter-duration and standard 1-year trastuzumab treatment. The hazard ratios (HRs) of disease-free survival (DFS) and overall survival (OS), and the odds ratios (ORs) of cardiac events were also estimated and pooled.
RESULTS: Six studies were eligible, including a total of 11,496 patients. Both DFS (HR = 1.13; 95% confidence interval [CI] = 1.03-1.25; p = 0.01) and OS (HR = 1.16; 95% CI = 1.01-1.32; p = 0.03) were significantly improved with conventional 1-year trastuzumab treatment compared with shorter treatments. The more pronounced survival benefits observed in patients with negative estrogen receptor (ER) tumor and nodal involvement should be interpreted cautiously because of the lack of interaction between the survival benefit and ER, as well as the nodal status (interaction test, ER status: p = 0.26; nodal status: p = 0.60). One year of trastuzumab treatment resulted in a substantial DFS benefit compared with shorter schedules when administered concurrently with chemotherapy (HR = 1.22; 95% CI = 1.09-1.38; p = 0.0008; p = 0.02 for the interaction test). Patients in the shorter duration group experienced significantly fewer cardiac events (OR = 0.52; 95% CI = 0.43-0.62; p < 0.00001).
CONCLUSIONS: Though correlated with an increasing risk of cardiotoxicity, 1 year of adjuvant trastuzumab treatment conferred substantial survival benefits and should remain as the preferred treatment for early stage HER2-positive breast cancer. Shorter durations of trastuzumab may serve as an alternative choice for patients with cardiac disease and those at lower risk of recurrence.

Since the discovery of the human epidermal growth factor receptor 2 (HER2) as an oncogenic driver in a subset of breast cancers and the development of HER2 directed therapies, the prognosis of

Most strategies used to prepare homogeneous site-specific antibody-drug conjugates (ADCs) result in ADCs with a drug-to-antibody ratio (DAR) of two. Here, we report a disulfide re-bridging strategy to prepare homogeneous ADCs with DAR of one using a dual-maleimide pyrrolobenzodiazepine (PBD) dimer (SG3710) and an engineered antibody (Flexmab), which has only one intrachain disulfide bridge at the hinge. We demonstrate that SG3710 efficiently re-bridge a Flexmab targeting human epidermal growth factor receptor 2 (HER2), and the resulting ADC was highly resistant to payload loss in serum and exhibited potent anti-tumor activity in a HER2-positive gastric carcinoma xenograft model. Moreover, this ADC was tolerated in rats at twice the dose compared to a site-specific ADC with DAR of two prepared using a single-maleimide PBD dimer (SG3249). Flexmab technologies, in combination with SG3710, provide a platform for generating site-specific homogenous PBD-based ADCs with DAR of one, which have improved biophysical properties and tolerability compared to conventional site-specific PBD-based ADCs with DAR of two.

A major limitation of traditional chemotherapy for cancer is dose-limiting toxicity, caused by the exposure of non-tumor cells to cytotoxic agents. Use of molecular targeted drugs, such as specific kinase inhibitors and monoclonal antibodies, is a possible solution to overcome this limitation and has achieved clinical success so far. Use of an antibody-drug conjugate (ADC) is a rational strategy for improving efficacy and reducing systemic adverse events. ADCs use antibodies selectively to deliver a potent cytotoxic agent to tumor cells, thus drastically improving the therapeutic index of chemotherapeutic agents. Lessons learned from clinical failure of early ADCs during the 1980s to 90s have recently led to improvements in ADC technology, and resulted in the approval of four novel ADCs. Nonetheless, further advances in ADC technology are still required to streamline their clinical efficacy and reduce toxicity. [fam-] Trastuzumab deruxtecan (DS-8201a) is a next-generation ADC that satisfies these requirements based on currently available evidence. DS-8201a has several innovative features; a highly potent novel payload with a high drug-to-antibody ratio, good homogeneity, a tumor-selective cleavable linker, stable linker-payload in circulation, and a short systemic half-life cytotoxic agent in vivo; the released cytotoxic payload could exert a bystander effect. With respect to its preclinical profiles, DS-8201a could provide a valuable therapy with a great potential against HER2-expressing cancers in clinical settings. In a phase I trial, DS-8201a showed acceptable safety profiles with potential therapeutic efficacy, with the wide therapeutic index.

Leptomeningeal carcinomatosis (LC) is defined as infiltration of the leptomeninges by metastatic carcinoma, a relatively uncommon but devastating complication of many malignancies. Although only 5% of patients with breast cancer develop leptomeningeal involvement, it remains the most common etiology of LC. It can occur as a late-stage complication of systemic progression or present as the first sign of metastatic disease, with or without parenchymal brain metastases. Lobular carcinomas have a higher propensity to metastasize into the meninges when compared to ductal carcinoma, especially the triple-negative subtype, which usually is associated with a shorter interval between metastatic breast cancer diagnosis and the development of LC. Prognosis remains poor, with median survival of 4 months for patients receiving state-of-the-art treatment. The main factors associated with survival are performance status at diagnosis, CSF protein level and triple-negative subtype. Headache is commonly the first clinical presentation of LC, and the diagnostic workup usually requires CSF-cytological analysis and or/MRI. The current management of LC consists of a combination of intra-CSF chemotherapy, systemic therapy, radiotherapy and/or best-supportive care. The standard intra-CSF chemotherapy regimen is methotrexate. Radiotherapy is used for relieving obstruction points on CSF-outflow channels due to ependymal nodules, tumor deposits or bulky disease. Objective responses have been reported with intrathecal administration of trastuzumab for HER2-positive disease, yet this strategy is still under investigation. Further prospective trials are needed to better address the impact of these treatment modalities on overall survival and quality of life.

RATIONALE: Primary squamous cell carcinoma (PSCC) of the breast is one of the least common types of breast cancer. Adjuvant treatment for PSCC remains an unresolved issue.
PATIENT CONCERNS: We reported a case of a 48-year-old postmenopausal female patients with a 2 × 2.5 cm lump presented with no symptoms.
DIAGNOSES: This patient was diagnosed as PSCC of the breast. The original tumor and first recurrence exhibited triple negative phenotype, whereas the second recurrence was HER2-positive.
INTERVENTIONS: A tumorectomy with latissimus dorsi flap reconstruction for the second recurrence was performed followed by targeted therapy with trastuzumab.
OUTCOMES: The patient had a complete remission, which was sustained over the 25 months of follow-up after the tumorectomy.
LESSONS: This is the first reported case in literature of a breast PSCC patient with switched immunohistochemical phenotypes during disease recurrence. Surgical resection with flap reconstruction and targeted therapy successfully treated the recurrence.

BACKGROUND: We characterized patterns of occurrence and the impact of neratinib-associated diarrhea in the absence of protocol-directed antidiarrheal prophylaxis or a formal diarrhea management plan using data from Extended Adjuvant Treatment of Breast Cancer with Neratinib (ExteNET).
METHODS: ExteNET is a multicenter, double-blind, placebo-controlled, randomized phase III trial involving community-based and academic institutions in 40 countries. Women with HER2-positive early-stage breast cancer with prior standard primary therapy and trastuzumab-based (neo)adjuvant therapy were randomized to neratinib 240 mg/day or placebo for 12 months. Safety, a secondary outcome, was assessed using the National Cancer Institute Common Terminology Criteria version 3.0. Health-related quality of life by diarrhea grade was assessed using Functional Assessment of Cancer Therapy-Breast (FACT-B).
RESULTS: Two thousand eight hundred sixteen women (1408 per group) were safety-evaluable. Grade 3 and 4 diarrhea occurred in 561 (39.8%) and 1 (0.1%) patients with neratinib versus 23 (1.6%) and 0 patients with placebo, respectively. In the neratinib group, 28.6% of patients had grade 3 events during month 1 decreasing to ≤ 6% after month 3. The median cumulative duration of grade 3/4 diarrhea with neratinib was 5 days (interquartile range, 2-9). Serious diarrheal events (n = 22, 1.6%) and diarrheal events requiring hospitalization (n = 20, 1.4%) were rare with neratinib. Changes in FACT-B total score by diarrhea grade in the neratinib group did not meet the threshold for clinically important differences.
CONCLUSIONS: In the absence of antidiarrheal prophylaxis, neratinib-related diarrhea is short-lived and not associated with complications or long-term sequelae. This suggests that targeted preventive management with antidiarrheal prophylaxis early during neratinib treatment is appropriate.
TRIAL REGISTRATION: ClinicalTrials.gov NCT00878709. Registered 9 April 2009.

PURPOSE: In adjuvant settings of human epidermal growth factor receptor 2 (HER2)-positive breast cancer, anthracycline-based chemotherapy followed by taxane and trastuzumab is a standard regimen. Recent studies have reported the use of anthracycline-free adjuvant chemotherapy in selected HER2-positive breast cancer patients. We conducted a single-center retrospective study to identify the characteristics of HER2-positive breast cancer patients for whom anthracyclines can be safely omitted.
METHODS: A total of 238 women were diagnosed with HER2-positive breast cancer and treated with neoadjuvant and/or adjuvant chemotherapy between January 1, 2008 and December 31, 2015 at Keio University Hospital. They were divided in two cohorts: an "anthracycline" cohort of 112 anthracycline-treated women and a "no anthracycline" cohort of 126 anthracycline-untreated women. Survival outcomes were estimated by Kaplan-Meier method.
RESULTS: The 3-year disease-free survival rates in the no-anthracycline and anthracycline cohorts were 91.3% and 93.1%, respectively (P = 0.692). After using a statistical method with inverse probability of treatment weighting to minimize the selection bias, no significant differences were observed between the two cohorts (adjusted hazard ratio for disease-free survival: 1.042; P = 0.909). Stratified by tumor size, no significant differences were observed between the two cohorts in the cT1N0 and cT2N0 subsets (P = 0.516 and P = 0.579, respectively). The recurrence rate was low among patients who achieved pathological complete response after receiving neoadjuvant chemotherapy with or without anthracyclines.
CONCLUSION: Our study suggests that anthracyclines can be safely omitted in selected patients with HER2-positive breast cancer, who have cT1N0 or cT2N0 and achieved pathological complete response after receiving neoadjuvant chemotherapy.

BACKGROUND: There are no established guidelines for the management of apocrine carcinomas of the breast; they are treated as a non-specific type of breast cancer.
CASE REPORT: We report on the case of a 40-year-old man who developed primary mediastinal apocrine carcinoma overexpressing human epidermal growth factor-2 (HER2). The patient initially underwent complete resection of a mediastinal mature teratoma with a focal apocrine carcinoma component. Two years after surgery, relapse was detected in multiple mediastinal lymph nodes. He received induction chemotherapy including docetaxel, trastuzumab, and pertuzumab; consolidative concurrent chemoradiation was added after six cycles. A complete response was confirmed using computed tomography following this multimodal therapy. After chemoradiation, adjuvant trastuzumab and pertuzumab were administered for 1 year and the patient has since had no evidence of progressive disease.
CONCLUSION: A multi-modal regimen that includes an anti-HER2 agent appears to be a promising treatment for patients with HER2-positive extramammary apocrine carcinoma.

BACKGROUND: The prognosis of stage IV gastric cancer and human epidermal growth factor 2 (HER2)-positive gastric cancer is poor, although new drugs and regimens have been developed. We report a case of a patient with stage IV HER2-positive gastric cancer treated successfully by conversion therapy and trastuzumab.
CASE PRESENTATION: The patient was a 73-year-old Japanese man diagnosed as L, type 3, circ, T4aNxCy1P1M1, stage IV (the Japanese classification of gastric carcinoma). The patient was treated with docetaxel, cisplatin, and TS-1 (DCS regimen). After two courses of the regimen, peritoneal dissemination disappeared, and peritoneal lavage cytology revealed no tumor cells in the abdominal cavity. Subsequently, he underwent laparoscopic distal gastrectomy with D1+. Pathological findings were ypT2(MP), ypN2(3/15), ypP0, ypCY0, M0, ypstage II. He received TS-1 as an adjuvant chemotherapy, but he had peritoneal recurrence. The original gastric cancer was HER2-positive. We therefore treated him with TS-1 with trastuzumab. This regimen was quite effective and achieved a complete response. After complete response, we switched the patient to trastuzumab monotherapy. He had no evidence of recurrence for 6 years, 3 months after surgery.
CONCLUSION: DCS regimen, R0 resection, and adjuvant chemotherapy with trastuzumab can be a powerful strategy for stage IV HER2-positive gastric cancer.