Abstract P3-13-01: Application of supine MRI-based 3D printing breast surgical guide for precision breast-conserving surgery

Background

If the size of the tumor is large, neoadjuvant systemic therapy (NST) is performed to reduce the size of the tumor and to conserve the breast. It is known that magnetic resonance imaging is more accurate than mammography (MMG) or ultrasonography (USG) in determining the area of residual cancer in breast-conserving surgery (BSG) after NST. However, there are some problems when performing BCS using MRI. Because the posture of MRI test is different from the posture at surgery, it is difficult to accurately mark the area of the tumor observed in MRI. Neoadjuvant systemic therapy reduces tumor size and often makes it difficult to detect the original tumor area on preoperative MRI. Even if the tumor is not visible in the image, the cancer cells may remain, so it is important to accurately indicate the extent of the initial tumor and remove it. Until now, however, there has been no way to accurately mark past breast tumors in the breast. We have developed a breast surgical guide (BSG) that can mark a range of tumor directly on the breast using three-dimensional printing technology based on supine MRI. This study analyzed the results of patients who underwent BCS using a 3D printing breast surgical guide (3D-BSG) based on supine MRI.

Methods

This trial was designed as a prospective single-institution cohort study. Our study protocol was approved by the Institutional Review Board of Asan Medical Center, Seoul, Korea (IRB No. 2016-1237). Patients who were expected to undergo BCS after NST were enrolled in this study and supine MRI was performed before and after NST. From MRI images, morphological shapes of breasts and tumors were modeled. The prepared digital model was saved in stereolithography file format and then exported to a 3D printer. 3D-BSG is designed to be able to mark the skin and attach the dye injecting column to mark the around the tumor. The breast tissue was removed with blue dye on the basis of the border. To obtain tumor free margin, intraoperative frozen sections were identified in several cavities and re-excision was performed if tumor positive.

Results

Between January 2016 and May 2017, 50 patients were enrolled in the study. BCS was applied to 40 patients, except for those who were rejected or mastectomy. Complete remission was observed in 15 patients after NST. Four patients had tumor positive on resection margins on frozen biopsy during operation, two with IDC and two with DCIS. Re-excision was performed in these patients and tumor negative margin was confirmed in all patients in the final pathology results. The median size of the long axis of the tumor was 1.7 cm (range, 0.5 to 4.5 cm) and the median size of the long axis of the removed breast tissue was 5.1 cm (range, 2.3 to 8.1 cm). The distance between tumor and resection margin was 1.2 cm (range, 0.1 to 4.8 cm)..

Conclusions

In BCS, the application of the supine MRI based 3D-BSG showed low rates of positive margins. Unlike conventional localization techniques, application of 3D-BSG does not cause pain to the patient, has no radiation exposure, and has no time required for the localization procedure, so it will be helpful for patients in BCS in the future.

Citation Format: Ko B, Kim N, Seo J, Kim H, Gong G, Kim S, Son B, Ahn SH. Application of supine MRI-based 3D printing breast surgical guide for precision breast-conserving surgery [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-13-01.

Abstract P6-17-03: 24 months results from a double-blind, randomized phase III trial comparing the efficacy and safety of neoadjuvant then adjuvant trastuzumab and its biosimilar candidate CT-P6 in HER2 positive early breast cancer (EBC)

Background CT-P6 is a proposed biosimilar to reference trastuzumab (RTZ). A double-blind, randomized, phase III trial showed similar efficacy and safety for CT-P6 and RTZ in HER2 positive EBC (NCT02162667). The primary endpoint, pathological complete response rate was within the predefined margin to demonstrate similarity (Lancet Oncol 2017). Safety and efficacy at 1 year (ESMO 2017), and cardiac toxicity at a median of 19 months (SABCS 2017) were similar between the two treatment groups. Here we report updated disease-free survival (DFS), overall survival (OS) and cardiac toxicity data with a median follow-up of 2 years.

Methods A total of 549 patients with HER2 positive EBC were randomized to receive CT-P6 (n=271) or RTZ (n=278) in combination with docetaxel (Cycles 1-4) and 5-fluorouracil, epirubicin and cyclophosphamide (Cycles 5-8). CT-P6 or RTZ was administered at 8 mg/kg (Cycle 1 only) followed by 6 mg/kg every 3 weeks. After surgery, patients received CT-P6 or RTZ monotherapy then entered the follow-up period up to 3 year of last patient enrollment. Time to event analyses were performed using Cox regression and Kaplan-Meier methods.

Results A total of 528 patients (259/271 in CT-P6 and 269/278 in RTZ) entered the follow-up period after completing therapy. The median follow-up duration was over 27 months. The number of DFS events (32 [12.4%] in CT-P6 and 26 [10.0%] in RTZ) and OS events (14 [5.2%] in CT-P6 and 12 [4.3%] in RTZ) were comparable in the ITT set. Additionally, DFS and OS were similar between CT-P6 group and RTZ group in both the per-protocol set (PPS) and the ITT set. In the ITT set, the proportion of 2-year DFS (95% CI) was 86% (80% – 90%) in CT-P6 and 90% (85% – 93%) in RTZ. The proportion of 2-year OS was 97% (93% – 98%) in CT-P6 and 98% (96% – 99%) in RTZ. Median DFS and OS have not been reached. After 1-year treatment, no new cases of heart failure were reported during the follow-up period. Left ventricular ejection fraction (LVEF) was similar in both groups (mean LVEF, more than 60%).

Table 1.Summary of Long Term Efficacy Endpoints PPSITT set CT-P6 (n=248)Reference Trastuzumab (n=256)CT-P6 (n=258)Reference Trastuzumab (n=261)Proportion of DFS1 year (95% CI)0.95 (0.91 – 0.97)0.96 (0.93 – 0.98)0.95 (0.91 – 0.97)0.96 (0.93 – 0.98)2 years (95% CI)0.86 (0.80 – 0.90)0.90 (0.85 – 0.93)0.86 (0.80 – 0.90)0.90 (0.85 – 0.93)p-value0.33240.3085 CT-P6 (n=248)Reference Trastuzumab (n=256)CT-P6 (n=271)Reference Trastuzumab (n=278)Proportion of OS1 year (95% CI)1.00 (1.00 – 1.00)1.00 (0.97 – 1.00)0.99 (0.97 – 1.00)0.99 (0.97 – 1.00)2 year (95% CI)0.97 (0.94 – 0.99)0.98 (0.96 – 0.99)0.97 (0.93 – 0.98)0.98 (0.96 – 0.99)3 year (95% CI)0.94 (0.88 – 0.97)0.93 (0.86 – 0.96)0.92 (0.86 – 0.96)0.93 (0.87 – 0.96)p-value0.93290.5057

Conclusions The efficacy and cardiac toxicity profile between CT-P6 and RTZ in EBC patients were consistent with published data. Time to event analyses as secondary efficacy endpoints supported the similarity for the two study drugs. CT-P6 was consistently well tolerated with a similar cardiotoxicity profile to that of RTZ through long duration of follow-up.

Citation Format: Esteva FJ, Lee S, Yu S, Kim M, Kim N, Stebbing J. 24 months results from a double-blind, randomized phase III trial comparing the efficacy and safety of neoadjuvant then adjuvant trastuzumab and its biosimilar candidate CT-P6 in HER2 positive early breast cancer (EBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-03.

3D printable hyaluronic acid-based hydrogel for its potential application as a bioink in tissue engineering

Background

After recognition of 3D printing and injectable hydrogel as a critical issue in tissue/organ engineering and regenerative medicine society, many hydrogels as bioinks have been developed worldwide by using polymeric biomaterials such as gelatin, alginate, hyaluronic acid and others. Even though some gels have shown good performances in 3D bioprinting, still their performances do not meet the requirements enough to be used as a bioink in tissue engineering.

Method

In this study, a hydrogel consisting of three biocompatible biomaterials such as hyaluronic acid (HA), hydroxyethyl acrylate (HEA) and gelatin-methacryloyl, i.e. HA-g-pHEA-gelatin gel, has been evaluated for its possibility as a bioprinting gel, a bioink. Hydrogel synthesis was obtained by graft polymerization of HEA to HA and then grafting of gelatin- methacryloyl via radical polymerization mechanism. Physical and biological properties of the HA-based hydrogels fabricated with different concentrations of methacrylic anhydride (6 and 8%) for gelatin-methacryloylation have been evaluated such as swelling, rheology, morphology, cell compatibility, and delivery of small molecular dimethyloxalylglycine. Printings of HA-g-pHEA-Gelatin gel and its bioink with bone cell loaded in lattice forms were also evaluated by using home-built multi-material (3D bio-) printing system.

Conclusion

The experimental results demonstrated that the HA-g-pHEA-gelatin hydrogel showed both stable rheology properties and excellent biocompatibility, and the gel showed printability in good shape. The bone cells in bioinks of the lattice-printed scaffolds were viable. This study showed HA-g-pHEA-Gelatin gel’s potential as a bioink or its tissue engineering applications in injectable and 3D bioprinting forms.

Predictive value of a fragmented QRS complex in diagnosing patients with myocardial ischemia

Background

A fragmented QRS complex (fQRS) is caused by conduction abnormalities of the ventricle secondary to myocardial ischemia and/or scar in patients with myocardial infarction. However, the implications of the fQRS in the development of coronary artery disease with myocardial ischemia in those without a scar remain unknown.

Methods

We studied electrocardiograms (ECGs) obtained from 150 patients (60.5 ± 8.5 years, 102 men) with myocardial ischemia, which was confirmed by performing both, a nuclear exercise stress test and coronary angiography. We also studied ECGs obtained from 601 patients (58.5 ± 10.0 years, 315 men) who showed a negative nuclear exercise stress test (control group). Patients in whom the nuclear exercise stress test showed a myocardial scar were excluded.

Results

An fQRS was more commonly observed in patients with myocardial ischemia (n = 48, 32.0%) than in the control group (n = 133, 22.1%) (P = 0.011). The sensitivity, specificity, positive, and negative predictive values of fQRS in diagnosing myocardial ischemia were 32.0, 77.9, 26.5, and 82.1%, respectively. The fQRS (odds ratio 1.580, 95% confidence interval 1.020‐2.446, P = 0.040) was an independent predictor of myocardial ischemia after adjusting for age, sex, current smoking habits, ST‐T changes on ECG, as well as histories of hypertension, diabetes, and dyslipidemia. Moreover, the fQRS showed an incremental prognostic value over conventional risk factors (χ² = 5, P = 0.032) and over a combination of conventional factors and ST‐T changes (χ² = 9, P = 0.014).

Conclusions

The fQRS is a moderately sensitive and independent predictor of myocardial ischemia.

Rapid and simultaneous quantification of a mixture of biopharmaceuticals by a liquid chromatography/quadrupole time-of-flight mass spectrometric method in rat plasma following cassette-dosing

RATIONALE

The cassette-dosing technique is a technique that administers various drugs to a single animal at once and quantitated simultaneously. The purpose of this study was to evaluate the feasibility of cassette-dosing as a means of increasing throughput and decreasing animal usage for pharmacokinetic studies of biopharmaceuticals using liquid chromatography/time-of-flight mass spectrometric (LC/TOF-MS) analysis.

METHODS

Brentuximab, trastuzumab, cetuximab and adalimumab were used as model biopharmaceuticals. The method consisted of immunoprecipitation followed by tryptic digestion for sample preparation and LC/TOF-MS analysis of specific signature peptides in the positive ion mode using electrospray ionization. The specific signature peptides used for quantification were from the complementarity-determining regions of each mAb. All rats received a single intravenous bolus injection containing either a single mAb or a mixture of four mAbs.

RESULTS

The proposed method has been qualified in linearity range of 1-100 μg/mL with correlation coefficients higher than 0.990. The qualification run met the acceptance criteria of ±25% accuracy and precision values for quality control (QC) samples. This qualified LC/TOF-MS method was successfully applied to a pharmacokinetic study in the rat. The PK properties of mAbs administered as a cassette-dosage were similar to the pharmacokinetics of each antibody drug when administered as a single entity.

CONCLUSIONS

These findings suggest that the cassette-dosing approach could be used to evaluate the PK properties of biopharmaceuticals in the early drug discovery stage. Also, this method would be useful for other preclinical sample analysis without developing new reagents for sample preparation.

Qualification and Application of a Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometric Method for the Determination of Adalimumab in Rat Plasma

A liquid chromatography–quadrupole time-of-flight (Q-TOF) mass spectrometric method was developed for early-stage research on adalimumab in rats. The method consisted of immunoprecipitation followed by tryptic digestion for sample preparation and LC-QTOF-MS/MS analysis of specific signature peptides of adalimumab in the positive ion mode using electrospray ionization. This specific signature peptide is derived from the complementarity-determining region (CDR) of adalimumab. A quadratic regression (weighted 1/concentration), with an equation y = ax² + bx + c, was used to fit calibration curves over the concentration range of 1–100 μg/mL for adalimumab. The qualification run met the acceptance criteria of ±25% accuracy and precision values for quality control (QC) samples. This qualified LC-QTOF-MS/MS method was successfully applied to a pharmacokinetic study of adalimumab in rats as a case study. This LC-QTOF-MS/MS approach would be useful as a complementary method for adalimumab or its biosimilars at an early stage of research.

A single liquid chromatography-quadrupole time-of-flight mass spectrometric method for the quantification of total antibody, antibody-conjugated drug and free payload of antibody-drug conjugates

A single hybrid affinity-captured-LC-TOF-MS/MS method was developed and applied for the quantification of total antibody, antibody conjugated drug and free payload of antibody drug conjugate (ADC). Adcetris®, a valine-citrulline monomethyl auristatin E conjugated ADC, was used as a model ADC compound. A quadratic regression (weighted 1/concentration) was used to fit calibration curves over the concentration range 30.65-613.00 ng/mL with an equation y = ax²  + bx + c for the antibody-conjugated drug of Adcetris®. The qualification run met the acceptance criteria of ±25% accuracy and precision values for quality control samples. For the analysis of total antibody, a signature peptide (TTPPVLDSDGSFFLYSK, molecular weight 1874) was used after affinity capture using magnetic beads and on-bead trypsin digestion. A quadratic regression (weighted 1/concentration) was used to fit calibration curves over the concentration range 5.00-100.00 μg/mL with an equation y = ax²  + bx + c for total antibody. For free payload analysis of monomethyl auristatin E, a protein precipitation method followed by LC-TOF-MS/MS analysis was used. A quadratic regression (weighted 1/concentration) was used to fit calibration curves over the concentration range 1.01-2200 ng/mL with an equation y = ax²  + bx + c for free payload. Pharmacokinetic study samples and in vitro stability samples in rat were successfully analyzed by this a hybrid affinity-captured-LC-TOF-MS/MS method. This single platform method is a useful complementary method for the pharmacokinetics study of ADC with valine-citrulline linker at the early drug discovery stage.

Reversibility of atrophic gastritis and intestinal metaplasia after Helicobacter pylori eradication - a prospective study for up to 10 years

BACKGROUND

Atrophic gastritis and intestinal metaplasia are premalignant conditions for gastric cancer. Their reversibility by Helicobacter pylori eradication remains controversial.

AIM

To evaluate the reversibility of atrophic gastritis and intestinal metaplasia by H. pylori eradication with long-term follow-up.

METHODS

598 subjects were prospectively enrolled and followed for up to 10 years. They were categorised as H. pylori-negative (n = 65), H. pylori non-eradicated (n = 91), and H. pylori-eradicated (n = 442). Histological assessment was performed for antrum and corpus by Sydney classification.

RESULTS

Histological follow-up was performed regularly at 1, 2, 3-4 and ≥5 years, with mean follow-up of 1.07 ± 0.21, 2.29 ± 0.83, 3.93 ± 1.02, and 6.45 ± 1.28 years, respectively. Atrophic gastritis in antrum and corpus gradually and significantly (both P < .05 for all timepoints) improved only in the H. pylori-eradicated group compared to that at baseline. Significant difference in atrophic gastritis between H. pylori-eradicated and H. pylori-negative groups disappeared from 1-year follow-up. Similarly, intestinal metaplasia in antrum and corpus improved significantly (both P < .05 for all timepoints) only in the H. pylori-eradicated group in comparison with that at baseline. Significant difference in intestinal metaplasia between H. pylori-eradicated and H. pylori-negative groups disappeared from ≥5 years of follow-up in the antrum and from 3 years of follow-up in the corpus.

CONCLUSION

H. pylori eradication may be a preventative strategy for intestinal-type gastric cancer by regression of atrophic gastritis and intestinal metaplasia.