Abstract P4-21-24: Development of mathematical prediction models to identify disease-free survival events for HER2-positive primary breast cancer patients treated by neoadjuvant chemotherapy and trastuzumab

Background)

The addition of trastuzumab to standard neoadjuvant chemotherapy (NAC) doubles the pathological complete response (pCR) rate in patients with HER2-positive primary breast cancer. Patients who achieved pCR after NAC with trastuzumab showed a better prognosis compared to those without pCR. However, it is still difficult to predict the likelihood of recurrence after surgery at an individual patient-level. The aim of this study was to develop a mathematical model to predict disease-free survival (DFS) events such as recurrence for patients treated with NAC and trastuzumab. Because brain metastasis (BM) often occurs in HER2-positive cancer patients and it is a particular event for those, we planned to develop a specific model for BM as well.

Patients and Methods)

Data of 776 HER2-positive primary breast cancer patients from the multicenter cohort study (JBCRG-C03) were used in the analysis. All patients had received NAC plus trastuzumab between 2001 and 2010. Two prediction models using a machine learning method (alternating decision tree algorithm) were developed using age, body-mass index, menopausal status, clinical stage, histological type, ER/PgR status, histological/nuclear grade, type of surgery, pathological response, adjuvant radiation therapy, and adjuvant hormonal therapy. The model A (DFS) predicted the probability of any disease recurrence, death by any cause, or secondary malignancy within 5 years after starting treatment. The model B (BM) predicted the probability of occurrence of BM within the 5 years. First, bias-controlled virtual datasets were generated for the training of the models using a resampling method. Second, the models were optimized by cross-validation (CV). Finally, the developed models were validated using the original dataset. The area under the receiver operating characteristics curve (AUC) was calculated to assess the discrimination ability of the models.

Results)

The DFS and BM event was observed in 118 and 30 patients, respectively. The AUC values for the model A and model B were 0.833 (95% CI, 0.798–0.868, P < 0.001) and 0.927 (95% CI, 0.905–0.949, P < 0.001), respectively. The sensitivity and specificity at the cut-off value of 50% were 72.0% and 78.4% for the model A, and 100% and 83.7% for the model B, respectively. Patients predicted as “low-risk” by the model A showed a significantly better 5-year DFS rate than “high-risk” patients (91.2% vs 53.8%, P < 0.001). Patients predicted as “low-risk” by the model B showed a significantly better 5-year BM-free survival rate than “high-risk” patients (100% vs 76.1%, P < 0.001). The discrimination ability of these models were maintained for both ER/PgR-positive and ER/PgR-negative subgroups, and also for both pCR and non-pCR subgroups.

Conclusions)

Our models showed high accuracy for predicting DFS events and BM in HER2-positive primary breast cancer patients treated with NAC and trastuzumab. These two models would help to realize accurate prediction of DFS events and to optimize the postoperative surveillance plan. The identification of high-risk patients for recurrence including BM may be useful for selecting a patient-subpopulation who requires new therapeutic approach.

Citation Format: Takada M, Sugimoto M, Masuda N, Iwata H, Kuroi K, Yamashiro H, Ohno S, Ishiguro H, Inamoto T, Toi M. Development of mathematical prediction models to identify disease-free survival events for HER2-positive primary breast cancer patients treated by neoadjuvant chemotherapy and trastuzumab [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 P4-21-24.

Potent acid inhibition by vonoprazan in comparison with esomeprazole, with reference to CYP2C19 genotype

BACKGROUND

Acid inhibitory effects of proton pump inhibitors (PPIs) are influenced by CYP2C19 genotype. In contrast, the potent acid inhibition of vonoprazan is not influenced by CYP2C19 genotype.

AIM

To compare the acid inhibitory effects of vonoprazan and esomeprazole in relation to CYP2C19 genotype.

METHODS

Twenty-eight healthy Japanese volunteers [7 CYP2C19 poor metabolisers (PMs), 11 intermediate metabolisers (IMs) and 10 rapid metabolisers (RMs)] received four different regimens in a randomised crossover manner: (i) vonoprazan 20 mg twice daily (b.d.), (ii) vonoprazan 20 mg daily, (iii) esomeprazole 20 mg b.d. and (iv) esomeprazole 20 mg daily. The timing of each dosing was 1 h before a meal. Twenty-four-hour intragastric pH monitoring was performed on day 7 on each regimen.

RESULTS

In the overall genotype group, pH ≥4 holding time ratios (pH 4 HTRs) with vonoprazan b.d., vonoprazan daily, esomeprazole b.d. and esomeprazole daily were 100%, 95%, 91%, and 68% respectively. pH 5 HTRs were 99%, 91%, 84% and 54% respectively. Vonoprazan b.d. potently suppressed acid for 24 h, and was significantly superior to other regimens irrespective of CYP2C19 genotype. Vonoprazan daily was equivalent to esomeprazole b.d. in IMs and PMs, but superior in RMs. CYP2C19 genotype-dependent differences were observed in esomeprazole daily but not in vonoprazan b.d. or daily.

CONCLUSION

Vonoprazan 20 mg b.d. inhibits acid irrespective of CYP2C19 genotype, more potently than esomeprazole 20 mg b.d., pH 4 and 5 holding time ratios reached 100% and 99%, respectively.

Operation and commissioning of IFMIF (International Fusion Materials Irradiation Facility) LIPAc injector

The objective of linear IFMIF prototype accelerator is to demonstrate 125 mA/CW deuterium ion beam acceleration up to 9 MeV. The injector has been developed in CEA Saclay and already demonstrated 140 mA/100 keV deuterium beam [R. Gobin et al., Rev. Sci. Instrum. 85, 02A918 (2014)]. The injector was disassembled and delivered to the International Fusion Energy Research Center in Rokkasho, Japan. After reassembling the injector, commissioning has started in 2014. Up to now, 100 keV/120 mA/CW hydrogen and 100 keV/90 mA/CW deuterium ion beams have been produced stably from a 10 mm diameter extraction aperture with a low beam emittance of 0.21 π mm mrad (rms, normalized). Neutron production by D-D reaction up to 2.4 × 10(9) n/s has been observed in the deuterium operation.

Positioning bedridden patients to reduce interface pressures over the sacrum and great trochanter

OBJECTIVE

In this study, we evaluated the effect of hip-joint rotation on the interface pressure over the sacrum and greater trochanter with a new protocol for positioning of bedridden elderly patients.

METHOD

The interface pressure values over the sacrum and greater trochanter in bedridden patients were evaluated. These were collected in the supine position, 90° lateral position, and 30° and 40° laterally inclined positions with external rotation or neutral positioning of the hip joint. Each interface pressure was assessed with a device measuring pressure distribution, after which, the peak pressure index (PPI) was calculated.

RESULTS

In the 17 patients examined, the PPI over the sacrum in the supine position was significantly greater than that in other positions. In the 30° and 40° laterally inclined positions, the PPIs over the greater trochanter were significantly lower in the neutral position of the hip joint compared with those in the external rotation position.

CONCLUSION

Our findings revealed the effects of hip-joint rotation on the interface pressure for the greater trochanter, possibly due to the increased distance between the greater trochanter and the sacrum caused by neutral position of the hip joint. The results demonstrate that it is to best place the hip joint in a neutral position when the legs are in contact with the bed in order to distribute the pressure over the greater trochanter in the 30° and 40° laterally inclined positions. These results can be applied to the clinical setting to improve patient positioning and decrease pressure ulcers.

DECLARATION OF INTEREST

The authors declare that they have no competing financial interests.

High Helicobacter pylori cure rate with sitafloxacin-based triple therapy

BACKGROUND

Bacterial resistance of Helicobacter pylori to antibiotics is increasing and it often leads to failure of antibiotic treatment. A new sitafloxacin-based triple therapy was developed to counter this situation; the fluoroquinolone sitafloxacin has a low minimum inhibitory concentration for H. pylori.

AIM

To investigate the efficacy in Japanese patients of sitafloxacin-based triple therapy and document its efficacy in relation to anti-microbial susceptibility.

METHODS

We investigated the efficacy of a 1-week sitafloxicin-based regimen of rabeprazole 10 mg four times daily (q.d.s.), metronidazole 250 mg twice daily (b.d.) and sitafloxacin 100 mg b.d. in 180 H. pylori-positive Japanese patients (first-line treatment: n = 45, second-line; n = 41, third-line: n = 94). At 8 weeks, patients were given the (13) C-urea breath test to assess eradication status.

RESULTS

Eradication rate was 92.2% [95% confidence interval (CI): 87.3-95.7%, 166/180] in intention-to-treat analysis. Although the eradication rate was higher in patients treated with first-line therapy [45/45 (100%, 95% CI: 83.4-100%)] than in those with second- [38/41 (92.7%, 80.1-98.5%)] or third-line therapy [83/94 (88.3%, 80.0-94.0%)], no significant differences were noted with respect to the number of previous therapy attempts (P = 0.054). Eradication rates in patients infected with sensitive- and resistant strains to metronidazole were 96.6% (28/29) and 96.3% (77/80) (P = 0.941), respectively, while rates were 98.4% (60/61) in sitafloxacin-sensitive and 50.0% (1/2) in sitafloxacin resistant strains (P < 0.001).

CONCLUSION

Sitofloxacin-based triple therapy with metronidazole b.d. and rabeprazole q.d.s. achieved an eradication rate exceeding 88%, irrespective of eradication history, CYP2C19 genotype, or metronidazole resistance status.

126 EXPRESSION OF MYO-INOSITOL OXYGENASE IN BOVINE PRE-IMPLANTATION EMBRYOS AND ITS REGULATION BY ANTI-OXIDATIVE VITAMINS

Myo-inositol (MI) added into in vitro culture media stimulates blastocyst development of mammals, including cattle (Holm et al. 1999 Theriogenology 52, 683–700), and these stimulatory effects are considered to be exerted via the incorporation of MI into phosphatidylinositol (Hynes et al. 2000 Mol. Reprod. Dev. 55, 265–269). Myo-inositol is catabolized by MI oxygenase (MIOX), which may affect bioavailability of MI for phosphatidylinositol pathway. In the present study, we investigated the expression pattern of MIOX transcripts in bovine pre-implantation embryos and the effects of anti-oxidative vitamins, which promote blastocyst hatching (Ikeda 2014 Reprod. Fertil. Dev. 26, 157), on the expression levels of MIOX in bovine blastocysts in vitro. Cumulus-enclosed oocytes obtained from slaughterhouse bovine ovaries were in vitro-matured for 22 h in modified SOF (mSOF) supplemented with 10% v/v FCS and 0.2 IU mL–1 FSH. After in vitro maturation, the oocytes were subjected to IVF with Percoll gradient-selected sperm in an mSOF-based medium for 20 h. After IVF, presumptive zygotes were freed from cumulus cells and cultured in mSOF up to Day 8 (IVF = Day 0). All cultures were performed at 38.5°C under 5% CO2, 5% O2, and 90% N2. Total RNA was extracted from embryos at the 1-cell, 2-cell, 8-cell, morula, and blastocyst stages (n = 15 × duplicates for each stage) and reverse transcribed to cDNA using oligo (dT) primer in a 31.5 μL reaction volume. Transcripts for MIOX were examined by quantitative reverse transcription-PCR (qRT-PCR) using 1 μL of the cDNA solution and succinate dehydrogenase as a reference gene. Moreover, IVF-derived 8- to 16-cell embryos on Day 3 were cultured in mSOF supplemented with or without a vitamin mix (11 μM a-tocopherol and 9 nM β-carotene) up to Day 8, and blastocysts (n = 10 × 3 replicates) were collected from each treatment. The expression levels of MIOX transcripts in the blastocysts were compared between the treatments by using qRT-PCR. The data were statistically analysed by Mann–Whitney U test. The MIOX transcripts were undetectable at the 1-cell and 2-cell stages and then expressed from the 8-cell stage onward. The vitamin treatment significantly (P < 0.05) decreased the expression level of MIOX in blastocysts. These results suggest that MIOX is one of embryonic-activated genes in bovine pre-implantation embryos, and the level of its expression is regulated by anti-oxidative vitamins. The stimulatory effects of anti-oxidative vitamins on blastocyst development might be in part via the modulation of MI bioavailability.

Survival of HER2-positive primary breast cancer patients treated by neoadjuvant chemotherapy plus trastuzumab: a multicenter retrospective observational study (JBCRG-C03 study)

We investigated the disease-free survival (DFS) of HER2-positive primary breast cancer patients treated with neoadjuvant chemotherapy plus trastuzumab, as well as predictive factors for DFS and pathologic response. Data from 829 female patients treated between 2001 and 2010 were collected from 38 institutions in Japan. Predictive factors were evaluated using multivariate analyses. The 3-year DFS rate was 87 % [95 % confidence interval (CI) 85-90]. The pathologic complete response (pCR: ypT0/is + ypN0) rate was 51 %. The pCR rate was higher in the ER/PgR-negative patients than in the ER/PgR-positive patients (64 vs. 36 %, P < 0.001). Patients with pCR showed a higher DFS rate than patients without pCR (93 vs. 82 %, P < 0.001). Multivariate analysis revealed three independent predictors for poorer DFS: advanced nodal stage [hazard ratio (HR) 2.63, 95 % CI 1.36-5.21, P = 0.004 for cN2-3 vs. cN0], histological/nuclear grade 3 (HR 1.81, 95 % CI 1.15-2.91, P = 0.011), and non-pCR (HR 1.98, 95 % CI 1.22-3.24, P = 0.005). In the ER/PgR-negative dataset, non-pCR (HR 2.63, 95 % CI 1.43-4.90, P = 0.002) and clinical tumor stage (HR 2.20, 95 % CI 1.16-4.20, P = 0.017 for cT3-4 vs. cT1-2) were independent predictors for DFS, and in the ER/PgR-positive dataset, histological grade of 3 (HR 3.09, 95 % CI 1.48-6.62, P = 0.003), clinical nodal stage (HR 4.26, 95 % CI 1.53-13.14, P = 0.005 for cN2-3 vs. cN0), and young age (HR 2.40, 95 % CI 1.12-4.94, P = 0.026 for ≤40 vs. >40) were negative predictors for DFS. Strict pCR (ypT0 + ypN0) was an independent predictor for DFS in both the ER/PgR-negative and -positive datasets (HR 2.66, 95 % CI 1.31-5.97, P = 0.006 and HR 3.86, 95 % CI 1.13-24.21, P = 0.029, respectively). These results may help assure a more accurate prognosis and personalized treatment for HER2-positive breast cancer patients.