Secretory Production of the Hericium erinaceus Laccase from Saccharomyces cerevisiae

Mushroom laccases play a crucial role in lignin depolymerization, one of the most critical challenges in lignin utilization. Importantly, laccases can utilize a wide range of substrates, such as toxicants and antibiotics. This study isolated a novel laccase, named HeLac4c, from endophytic white-rot fungi Hericium erinaceus mushrooms. The cDNAs for this enzyme were 1569 bp in length and encoded a protein of 523 amino acids, including a 20 amino-acid signal peptide. Active extracellular production of glycosylated laccases from Saccharomyces cerevisiae was successfully achieved by selecting an optimal translational fusion partner. We observed that 5 and 10 mM Ca2+, Zn2+, and K+ increased laccase activity, whereas 5 mM Fe2+ and Al3+ inhibited laccase activity. The laccase activity was inhibited by the addition of low concentrations of sodium azide and L-cysteine. The optimal pH for the 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt was 4.4. Guaiacylglycerol-β-guaiacyl ether, a lignin model compound, was polymerized by the HeLac4c enzyme. These results indicated that HeLac4c is a novel oxidase biocatalyst for the bioconversion of lignin into value-added products for environmental biotechnological applications.

Insights into Enzyme Reactions with Redox Cofactors in Biological Conversion of CO2

Carbon dioxide (CO2) is the most abundant component of greenhouse gases (GHGs) and directly creates environmental issues such as global warming and climate change. Carbon capture and storage have been proposed mainly to solve the problem of increasing CO2 concentration in the atmosphere; however, more emphasis has recently been placed on its use. Among the many methods of using CO2, one of the key environmentally friendly technologies involves biologically converting CO2 into other organic substances such as biofuels, chemicals, and biomass via various metabolic pathways. Although an efficient biocatalyst for industrial applications has not yet been developed, biological CO2 conversion is the needed direction. To this end, this review briefly summarizes seven known natural CO2 fixation pathways according to carbon number and describes recent studies in which natural CO2 assimilation systems have been applied to heterogeneous in vivo and in vitro systems. In addition, studies on the production of methanol through the reduction of CO2 are introduced. The importance of redox cofactors, which are often overlooked in the CO2 assimilation reaction by enzymes, is presented; methods for their recycling are proposed. Although more research is needed, biological CO2 conversion will play an important role in reducing GHG emissions and producing useful substances in terms of resource cycling.

Modulation of Kex2p Cleavage Site for In Vitro Processing of Recombinant Proteins Produced by Saccharomyces cerevisiae

Kex2 protease (Kex2p) is a membrane-bound serine protease responsible for the proteolytic maturation of various secretory proteins by cleaving after dibasic residues in the late Golgi network. In this study, we present an application of Kex2p as an alternative endoprotease for the in vitro processing of recombinant fusion proteins produced by the yeast Saccharomyces cerevisiae. The proteins were expressed with a fusion partner connected by a Kex2p cleavage sequence for enhanced expression and easy purification. To avoid in vivo processing of fusion proteins by Kex2p during secretion and to guarantee efficient removal of the fusion partners by in vitro Kex2p processing, P1', P2', P4, and P3 sites of Kex2p cleavage sites were elaborately manipulated. The general use of Kex2p in recombinant protein production was confirmed using several recombinant proteins.

Development of novel recombinant peroxidase secretion system from Pseudomonas putida for lignin valorisation

Pseudomonas putida is a promising strain for lignin valorisation. However, there is a dearth of stable and efficient systems for secreting enzymes to enhance the process. Therefore, a novel secretion system for recombinant lignin-depolymerising peroxidase was developed. By adopting a flagellar type III secretion system, P. putida KT-M2, a secretory host strain, was constructed and an optimal secretion signal fusion partner was identified. Application of the dye-decolourising peroxidase of P. putida to this system resulted in efficient oxidation activity of the cell-free supernatant against various chemicals, including lignin model compounds. This peroxidase-secreting strain was examined to confirm its lignin utilisation capability, resulting in the efficient assimilation of various lignin substrates with 2.6-fold higher growth than that of the wild-type strain after 72 h of cultivation. Finally, this novel system will lead efficient bacterial lignin breakdown and utilization through enzyme secretion, paving the way for sustainable lignin-consolidated bioprocessing.

Dual-functional carboxymethyl levan-based protein carrier for cosmeceutical application of human epidermal growth factor

Human epidermal growth factor (hEGF) has been a subject of extensive research as its wide range of physiological functions has many potential applications. However, due to the low stability of hEGF, its physiological effect is easily lost under conditions of use. To compensate for this, we developed a stable delivery system using levan-based nanoparticles. The entrapment yield of various tested proteins was significantly improved by employing carboxymethyl levan (CML) instead of levan; the entrapment yield of the CML-hEGF nanoparticles was 84.1 %. The size and zeta potential of the nanoparticles were identified as 199.9 ± 3.87 nm and -19.1 mV, respectively, using scanning electron microscopy (SEM) and particle size analysis. Dual biological functions of the nanoparticles (skin regeneration and moisturizing) were identified through collagen synthesis activity and aquaporin 3 expression level analysis. Stability of the prepared nanoparticles was also investigated via cell proliferation activity comparison under mimicked physiological conditions. The CML-hEGF nanoparticles maintained cell proliferation activity over 100 % for 6 weeks, while free hEGF was almost inactivated within 2 weeks. Taken together, our results indicate that the CML-based hEGF nanoparticles can be used in pharma- and cosmeceutical applications, guaranteeing a high entrapment capability, functionality, and stability.

Diagnosis of ultrafast surface dynamics of thin foil targets irradiated by intense laser pulses

The temporal modulation of an electron bunch train accelerated from a foil target irradiated by an intense laser pulse is studied by measuring the coherent transition radiation (CTR) from the rear surface of a target. We experimentally obtained CTR spectra from a 1 µm thick foil target irradiated at a maximum intensity of 6.5 × 10¹⁹ W/cm². Spectral redshifts of the emitted radiation corresponding to increases in laser intensity were observed. These measurements were compared with the theoretical calculation of CTR spectra considering ultrafast surface dynamics, such as plasma surface oscillation and relativistically induced transparency. Plasma surface oscillations induce a spectral redshift, while relativistic transparency causes a spectral blueshift. Both effects are required to find reasonable agreement with the experiment over the entire range of laser intensities.

Fructan Biosynthesis by Yeast Cell Factories

Fructan is a polysaccharide composed of fructose and can be classified into several types, such as inulin, levan, and fructo-oligosaccharides, based on their linkage patterns and degree of polymerization. Owing to its structural and functional diversity, fructan has been used in various fields including prebiotics, foods and beverages, cosmetics, and pharmaceutical applications. With increasing interest in fructans, efficient and straightforward production methods have been explored. Since the 1990s, yeast cells have been employed as producers of recombinant enzymes for enzymatic conversion of fructans including fructosyltransferases derived from various microbes and plants. More recently, yeast cell factories are highlighted as efficient workhorses for fructan production by direct fermentation. In this review, recent advances and strategies for fructan biosynthesis by yeast cell factories are discussed.

Production of autolysis-proof Kex2 protease from Candida albicans in Saccharomyces cerevisiae for in vitro processing of fusion proteins

Protein expression with a fusion partner followed by the removal of the fusion partner via in vitro processing with a specific endoprotease is a favored method for the efficient production of intact recombinant proteins. Due to the high cost of commercial endoproteases, this process is restricted to laboratories. Kex2p is a membrane-bound serine protease that cleaves after dibasic residues of substrates in the late Golgi network. Although Kex2p is a very efficient endoprotease with exceptional specificity, it has not yet been used for the in vitro processing of fusion proteins due to its autolysis and high production cost. In this study, we developed an alternative endoprotease, autolysis-proof Kex2p, via site-directed mutagenesis of truncated KEX2 from Candida albicans (CaKEX2). Secretory production of manipulated CaKex2p was improved by employing target protein-specific translational fusion partner in Saccharomyces cerevisiae. The mass production of autolysis-proof Kex2p could facilitate the use of Kex2p for the large-scale production of recombinant proteins. KEY POINTS: • A soluble and active CaKex2p variant was produced by autocatalytic cleavage of the pro-peptide after truncation of C-terminus • Autolysis-proof CaKex2p was developed by site-directed mutagenesis • Secretion of autolysis-proof CaKex2p was improved by employing optimal translational fusion partner in Saccharomyces cerevisiae.

Characterization of Acyl-CoA Oxidases from the Lipolytic Yeast Candida aaseri SH14

The lipolytic yeast Candida aaseri SH14 contains three Acyl-CoA oxidases (ACOXs) which are encoded by the CaAOX2, CaAOX4, and CaAOX5 genes and catalyze the first reaction in the β-oxidation of fatty acids. Here, the respective functions of the three CaAOX isozymes were studied by growth analysis of mutant strains constructed by a combination of three CaAOX mutations in minimal medium containing fatty acid as the sole carbon source. Substrate specificity of the CaAOX isozymes was analyzed using recombinant C. aaseri SH14 strains overexpressing the respective genes. CaAOX2 isozyme showed substrate specificity toward short- and medium-chain fatty acids (C6-C12), while CaAOX5 isozyme preferred long-chain fatty acid longer than C12. CaAOX4 isozyme revealed a preference for a broad substrate spectrum from C6-C16. Although the substrate specificity of CaAOX2 and CaAOX5 covers medium- and long-chain fatty acids, these two isozymes were insufficient for complete β-oxidation of long-chain fatty acids, and therefore CaAOX4 was indispensable.

Secretome-based screening of fusion partners and their application in recombinant protein secretion in Saccharomyces cerevisiae

For the efficient production of heterologous proteins in the yeast Saccharomyces cerevisiae, we screened for a novel fusion partner from the yeast secretome. From twenty major proteins identified from the yeast secretome, we selected Scw4p, a cell wall protein with similarity to glucanase, and modified to develop a general fusion partner for the secretory expression of heterologous proteins in yeast. The optimal size of the SCW4 gene to act as an efficient fusion partner was determined by C-terminal truncation analysis; two of the variants, S1 (truncated at codon 115Q) and S2 (truncated at codon 142E), were further used for the secretion of heterologous proteins. When fused with S2, the secretion of three target proteins (hGH, exendin-4, and hPTH) significantly increased. Conserved O-glycosylation sites (Ser/Thr-rich domain) and hydrophilic sequences of S2 were deemed important for the function of S2 as a secretion fusion partner. Approximately 5 g/L of the S2-exendin-4 fusion protein was obtained from fed-batch fermentation. Intact target proteins were easily purified by affinity chromatography after in vitro processing of the fusion partner. This system may be of general application for the secretory production of heterologous proteins in S. cerevisiae. KEY POINTS : • Target proteins were efficiently secreted with their N-terminus fused to Scw4p. • O-glycosylation and hydrophilic stretches in Scw4p were important for protein secretion. • A variant of Scw4p (S2) was successfully applied for the secretory expression of heterologous proteins.

A novel protein fusion partner, carbohydrate-binding module family 66, to enhance heterologous protein expression in Escherichia coli

Background

Proteins with novel functions or advanced activities developed by various protein engineering techniques must have sufficient solubility to retain their bioactivity. However, inactive protein aggregates are frequently produced during heterologous protein expression in Escherichia coli. To prevent the formation of inclusion bodies, fusion tag technology has been commonly employed, owing to its good performance in soluble expression of target proteins, ease of application, and purification feasibility. Thus, researchers have continuously developed novel fusion tags to expand the expression capacity of high-value proteins in E. coli.

Results

A novel fusion tag comprising carbohydrate-binding module 66 (CBM66) was developed for the soluble expression of heterologous proteins in E. coli. The target protein solubilization capacity of the CBM66 tag was verified using seven proteins that are poorly expressed or form inclusion bodies in E. coli: four human-derived signaling polypeptides and three microbial enzymes. Compared to native proteins, CBM66-fused proteins exhibited improved solubility and high production titer. The protein-solubilizing effect of the CBM66 tag was compared with that of two commercial tags, maltose-binding protein and glutathione-S-transferase, using poly(ethylene terephthalate) hydrolase (PETase) as a model protein; CBM66 fusion resulted in a 3.7-fold higher expression amount of soluble PETase (approximately 370 mg/L) compared to fusion with the other commercial tags. The intact PETase was purified from the fusion protein upon serial treatment with enterokinase and affinity chromatography using levan-agarose resin. The bioactivity of the three proteins assessed was maintained even when the CBM66 tag was fused.

Conclusions

The use of the CBM66 tag to improve soluble protein expression facilitates the easy and economic production of high-value proteins in E. coli.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12934-021-01725-w.

Directed evolution and secretory expression of xylose isomerase for improved utilisation of xylose in Saccharomyces cerevisiae

BACKGROUND

Xylose contained in lignocellulosic biomass is an attractive carbon substrate for economically viable conversion to bioethanol. Extensive research has been conducted on xylose fermentation using recombinant Saccharomyces cerevisiae expressing xylose isomerase (XI) and xylose reductase/xylitol dehydrogenase (XR/XDH) pathways along with the introduction of a xylose transporter and amplification of the downstream pathway. However, the low utilization of xylose in the presence of glucose, due to the varying preference for cellular uptake, is a lingering challenge. Studies so far have mainly focused on xylose utilization inside the cells, but there have been little trials on the conversion of xylose to xylulose by cell before uptake. We hypothesized that the extracellular conversion of xylose to xylulose before uptake would facilitate better utilization of xylose even in the presence of glucose. To verify this, XI from Piromyces sp. was engineered and hyper-secreted in S. cerevisiae for the extracellular conversion of xylose to xylulose.

RESULTS

The optimal pH of XI was lowered from 7.0 to 5.0 by directed evolution to ensure its high activity under the acidic conditions used for yeast fermentation, and hyper-secretion of an engineered XI-76 mutant (E56A and I252M) was accomplished by employing target protein-specific translational fusion partners. The purified XI-76 showed twofold higher activity than that of the wild type at pH 5. The secretory expression of XI-76 in the previously developed xylose utilizing yeast strain, SR8 increased xylose consumption and ethanol production by approximately 7-20% and 15-20% in xylose fermentation and glucose and xylose co-fermentation, respectively.

CONCLUSIONS

Isomerisation of xylose to xylulose before uptake using extracellular XI was found to be effective in xylose fermentation or glucose/xylose co-fermentation. This suggested that glucose competed less with xylulose than with xylose for uptake by the cell. Consequently, the engineered XI secretion system constructed in this study can pave the way for simultaneous utilization of C5/C6 sugars from the sustainable lignocellulosic biomass.

Adhesive Antimicrobial Peptides Containing 3,4-Dihydroxy-L-Phenylalanine Residues for Direct One-Step Surface Coating

Bacterial colonization and transmission via surfaces increase the risk of infection. In this study, we design and employ novel adhesive antimicrobial peptides to prevent bacterial contamination of surfaces. Repeats of 3,4-dihydroxy-L-phenylalanine (DOPA) were added to the C-terminus of NKC, a potent synthetic antimicrobial peptide, and the adhesiveness and antibacterial properties of the resulting peptides are evaluated. The peptide is successfully immobilized on polystyrene, titanium, and polydimethylsiloxane surfaces within 10 min in a one-step coating process with no prior surface functionalization. The antibacterial effectiveness of the NKC-DOPA₅-coated polystyrene, titanium, and polydimethylsiloxane surfaces is confirmed by complete inhibition of the growth of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus within 2 h. The stability of the peptide coated on the substrate surface is maintained for 84 days, as confirmed by its bactericidal activity. Additionally, the NKC-DOPA₅-coated polystyrene, titanium, and polydimethylsiloxane surfaces show no cytotoxicity toward the human keratinocyte cell line HaCaT. The antimicrobial properties of the peptide-coated surfaces are confirmed in a subcutaneous implantation animal model. The adhesive antimicrobial peptide developed in this study exhibits potential as an antimicrobial surface-coating agent for efficiently killing a broad spectrum of bacteria on contact.

Genetic Manipulation of a Lipolytic Yeast Candida aaseri SH14 Using CRISPR-Cas9 System

A lipolytic yeast Candida aaseri SH14 that can utilise long-chain fatty acids as the sole carbon source was isolated from oil palm compost. To develop this strain as a platform yeast for the production of bio-based chemicals from renewable plant oils, a genetic manipulation system using CRISPR-Cas9 was developed. Episomal vectors for expression of Cas9 and sgRNA were constructed using an autonomously replicating sequence isolated from C. aaseri SH14. This system guaranteed temporal expression of Cas9 for genetic manipulation and rapid curing of the vector from transformed strains. A β-oxidation mutant was directly constructed by simultaneous disruption of six copies of acyl-CoA oxidases genes (AOX2, AOX4 and AOX5) in diploid cells using a single sgRNA with 70% efficiency and the Cas9 vector was efficiently removed. Blocking of β-oxidation in the triple AOX mutant was confirmed by the accumulation of dodecanedioic acid from dodecane. Targeted integration of the expression cassette for C. aaseri lipase2 was demonstrated with 60% efficiency using this CRISPR-Cas9 system. This genome engineering tool could accelerate industrial application of C. aaseri SH14 for production of bio-based chemicals from renewable oils.

Recurrence following hemithyroidectomy in patients with low- and intermediate-risk papillary thyroid carcinoma

BACKGROUND

This study evaluated the incidence, patterns and risk factors for recurrence after hemithyroidectomy in patients with low- and intermediate-risk papillary thyroid carcinoma (PTC), and verified the predictive role of the risk staging systems in current use.

METHODS

The clinicopathological characteristics and risk categories were analysed according to recurrence in patients who underwent hemithyroidectomy for low- and intermediate-risk conventional PTC, and were followed up for at least 24 months. Five risk staging systems were used to stratify risk: the 2015 American Thyroid Association (ATA) system; Age, Metastases, Extent and Size (AMES) system; Metastases, Age, Complete resection, Invasion and Size (MACIS) system; Grade, Age, Metastases, Extent and Size (GAMES) system; and the eighth AJCC system.

RESULTS

The study included 561 patients; 93·9 per cent of the study population (527 of 561) had a papillary thyroid microcarcinoma 1 cm or smaller in size. At a mean follow-up of 83 months, 25 patients (4·5 per cent) had recurrence; among these patients, 23 (92%) presented with a remaining thyroid lobe. Multifocality was significantly associated with recurrence in univariable and multivariable analyses (adjusted hazard ratio 3·16, 95 per cent c.i. 1·25 to 7·98; P = 0·015). Disease-free survival (DFS) varied according to multifocality (P = 0·010). The five risk staging systems were not associated with recurrence, and their Harrell's C-index ranged from 0·500 to 0·531. DFS rates did not differ between the risk categories in each system.

CONCLUSION

Although the recurrence rate after hemithyroidectomy in patients with low- and intermediate-risk PTC was low, meticulous follow-up focusing on the remaining thyroid lobe is needed for early detection and timely management of recurrence. The risk scoring systems in current use have no predictive role in these patients.

Site saturation mutagenesis of ribosomal protein L42 at 56th residue and application as a consecutive selection marker for cycloheximide resistance in yeast

The 56th residue of ribosomal protein L42 (Rpl42) determines the sensitivity of yeast cells to the antibiotic cycloheximide (CYH). In this study, we identified the relationship between the 56th residue of Rpl42 and the function of the ribosome by site saturation mutagenesis. The resulting 20 RPL42 mutants harbouring one of 20 amino acids at the 56th residue were classified into five groups: sensitive to CYH (RPL42aP); weak resistance (RPL42aA, RPL42aM, RPL42aC, RPL42aN, RPL42aD, RPL42aS and RPL42aT), moderate resistance (RPL42aL, RPL42aI, RPL42aV, RPL42aG and RPL42aH), and strong resistance (RPL42aQ, RPL42aE, RPL42aR and RPL42aK) to CYH; and non-functional (RPL42aF, RPL42aY and RPL42aW). Three RPL42a mutants from each group, RPL42aA, RPL42aL and RPL42aQ, were used as CYH-resistant selection marker genes for the sequential transformation of CYH-sensitive yeast. A series of RPL42 mutants conferring different levels of resistance to CYH should be useful for the dose-dependent multiple selection of prototrophic industrial yeasts.

Bacterial Valorization of Lignin: Strains, Enzymes, Conversion Pathways, Biosensors, and Perspectives

Lignin, an aromatic polymer found in plants, has been studied for years in many biological fields. Initially, when biofuel was produced from lignocellulosic biomass, lignin was regarded as waste generated by the biorefinery and had to be removed, because of its inhibitory effects on fermentative bacteria. Although it has since proven to be a natural resource for bio-products with considerable potential, its utilization is confined by its complex structure. Hence, the microbial degradation of lignin has attracted researchers' interest to overcome this problem. From this perspective, the studies have primarily focused on fungal systems, such as extracellular peroxidase and laccase from white- and brown-rot fungi. However, recent reports have suggested that bacteria play an increasing role in breaking down lignin. This paper, therefore, reviews the role of bacteria in lignin and lignin-related research. Several reports on bacterial species in soil that can degrade lignin and their enzymes are included. In addition, a cellulolytic anaerobic bacterium capable of solubilizing lignin and carbohydrate simultaneously has recently been identified, even though the enzyme involved has not been discovered yet. The assimilation of lignin-derived small molecules and their conversion to renewable chemicals by bacteria, such as muconic acid and polyhydroxyalkanoates, including genetic modification to enhance their capability was discussed. This review also covers the indirect use of bacteria for lignin degradation, which is concerned with whole-cell biosensors designed to detect the aromatic chemicals released from lignin transformation.

Efficient production of levan using a recombinant yeast Saccharomyces cerevisiae hypersecreting a bacterial levansucrase

Levan is a fructose polymer with diverse applications in the food and medical industries. In this study, levansucrase from Rahnella aquatilis (RaLsrA) was hyper-secreted using a Saccharomyces cerevisiae protein secretion system. An optimal secretion signal, a translation fusion partner (TFP) containing an N-terminal 98 amino acid domain from a mitochondrial inner membrane protein, UTH1, was employed to secrete approximately 50 U/mL of bioactive RaLsrA into culture media with 63% secretion efficiency by fed-batch fermentation. Although the purified RaLsrA was useful for enzymatic conversion of high-molecular-weight levan of approximately 3.75 × 10⁶ Da, recombinant yeast secreting RaLsrA could produce levan more efficiently by microbial fermentation. In a 50-L scale fermenter, 76-g/L levan was directly converted from 191-g/L sucrose by recombinant yeast cells, attaining an 80% conversion yield and 3.17-g/L/h productivity. Thus, we developed a cost-effective and industrially applicable production system for food-grade levan.

Abstract P6-17-23: Randomized phase II study of lapatinib plus vinorelbine versus vinorelbine in patients with HER2 positive metastatic breast cancer progressed after lapatinib and trastuzumab treatment

Background

The continuum of anti-HER2 agents is regarded as a standard strategy for HER2 positive metastatic breast cancer patients who had progressed disease with anti-HER2 agent- containing treatments. However, there has been lack of data on which agents should be continued and how long continuous anti-HER2 therapies would be effective. This study was aimed to evaluate the efficacy of lapatinib plus vinorelbine in HER2 positive metastatic breast cancer patients who had progressed on both trastuzumab and lapatinib treatments.

Methods

A total of 149 patients were randomly assigned to lapatinib with vinorelbine (LV) (n=75; laptinib, 1000mg daily ; vinorelbine 20mg/m2 D1,D8 q3w) or vinorelbine alone (V) (n=74; 30mg/m2 D1,D8 q3w). The stratification factors were followings; 1) visceral metastasis, 2) previous response to lapatinib treatment, CR+PR vs. SD ≥ 12 weeks. The primary endpoint was progression free survival (PFS) rate at 18 weeks. The secondary endpoints were objective response rate (ORR), PFS, and overall survival (OS).

Results :

Both arms were well balanced in various clinical factors. The median number of previous anti-HER2 therapies were 2 (range 2-5). There was no significant difference in PFS rate at 18 weeks between LV and V arms (44.0% vs 36.5%, p=0.44). ORR was 19.7% in LV arm and 16.9% in V arm (p=0.881). PFS and OS did not differ between two arms (LV vs V; median PFS, 16weeks vs 12 weeks, HR= 0.86, 95% CI 0.61-1.22, p=0.41; median OS, 15.0 months vs 18.9 months, HR= 1.07, 95% CI 0.72-1.58, p=0.72). In subgroup analysis, there was no difference in PFS and OS between two arms according to previous response to lapatinib (median PFS, CR+PR vs. SD ≥ 12 weeks, 12.1weeks vs.17.4 weeks; HR= 1.242, 95% CI 0.881-1.751, p=0.215; median OS, 14.9 months vs. 19.4 months; HR= 1.179, 95% CI 0.797-1.744, p=0.41). Most common adverse events in both arms were neutropenia which was more often observed in V arm (55% vs 73%, p=0.03). Overall, the profiles of adverse events were similar in both arms and all were manageable.

Conclusion

Lapatinib plus vinorelbine treatment was tolerable, however, it did not demonstrate the clinical benefits compared to vinorelbine alone in HER2 positive metastatic breast cancer patients after progression on both trastuzumab and lapatinib.

Citation Format: Sim SH, Park IH, Jung KH, Kim S-B, Ahn J-H, Lee K-H, Im S-A, Im Y-H, Park YH, Sohn JH, Kim YJ, Lee S, Kim H-J, Chae YS, Park K-H, Nam B-H, Lee KS, Ro J. Randomized phase II study of lapatinib plus vinorelbine versus vinorelbine in patients with HER2 positive metastatic breast cancer progressed after lapatinib and trastuzumab treatment [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 P6-17-23.

Development of Bacillus methanolicus methanol dehydrogenase with improved formaldehyde reduction activity

Methanol dehydrogenase (MDH), an NAD⁺-dependent oxidoreductase, reversibly converts formaldehyde to methanol. This activity is a key step for both toxic formaldehyde elimination and methanol production in bacterial methylotrophy. We mutated decameric Bacillus methanolicus MDH by directed evolution and screened mutants for increased formaldehyde reduction activity in Escherichia coli. The mutant with the highest formaldehyde reduction activity had three amino acid substitutions: F213V, F289L, and F356S. To identify the individual contributions of these residues to the increased reduction activity, the activities of mutant variants were evaluated. F213V/F289L and F213V/F289L/F356S showed 25.3- and 52.8-fold higher catalytic efficiency (k_cat/K_m) than wild type MDH, respectively. In addition, they converted 5.9- and 6.4-fold more formaldehyde to methanol in vitro than the wild type enzyme. Computational modelling revealed that the three substituted residues were located at MDH oligomerization interfaces, and may influence oligomerization stability: F213V aids in dimer formation, and F289L and F356S in decamer formation. The substitutions may stabilise oligomerization, thereby increasing the formaldehyde reduction activity of MDH.

Abstract P2-09-21: Molecular alterations and poziotinib, a pan-HER inhibitor efficacy in human epidermal growth factor receptor 2(HER2) positive breast cancers: Combined exploratory biomarker analysis from phase II clinical trial of poziotinib for refractory HER2 positive breast cancer(BC) patients

Introduction: Poziotinib is a novel, pan-HER kinase inhibitor which showed potent anti-tumor activities through irreversible inhibition of HER family tyrosine kinases in preclinical and early clinical studies. Recent the open-label, multicenter phase II trial of poziotinib monotherapy evaluated that poziotinib is a new promising option for patients with HER2-positive metastatic BC who have failed more than two HER2 targeted therapy (NCT02418689). We evaluated genetic profiles of HER2-positive metastatic BC and investigated potential biomarkers of poziotinib for HER2-positive metastatic BC (MBC). Methods: All participants were diagnosed as HER2-positive BCs according to American Society of Clinical Oncology/College of American Pathologists HER2 guideline and provided tissue specimens that would be possible to extract DNA and RNA for next generation sequencing. We performed targeted deep sequencing with a customized 381 cancer gene panel (CancerSCAN™) and analyzed the relationship among the sequencing data, immunohistochemistry and clinical outcome.

Results: From Apr 2015 to Feb 2016, 106 patients were enrolled in the trial from 7 institutes in Korea. Of 106 patients, biomarker data were available for 79 patients. TP53 was the most frequently mutated gene (70.8%) followed by PIK3CA (45.6%). HER2 single nucleotide variant (SNV) was detected in 13 BCs (16.5%) and HER3 SNV was in 9 (11.4%). The score of HER2 immunohistochemistry (IHC) was 3+ in 68 BCs and 2+ with positive in situ hybridization in 11 BCs. In copy number variant (CNV) analysis, HER2 amplification (86.1%) was most frequently observed and followed by CDK12 amplification (58.2%) and APOBEC3B deletion (30.4%). IHC score of HER2 was positively correlated to copy number (CN) of HER2 (P=0.001) but 11 breast cancer tissue did not have copy number amplification of HER2 (13.9%) (Six of HER2 IHC score 2+ and 5 of 3+). The median progression free survival (PFS) was 4.04 months (95% CI, 2.96 - 4.40) for patients who treated with poziotinib in this study. PIK3CA activating mutations were associated with short PFS compared to wild type (WT) and other SNVs (Median PFS of activating mutations vs. WT and others: 2.66 vs. 4.40 (months), P=0.009). HER2 CN amplification was positively correlated to duration of PFS (Median PFS of no amplification vs. 4 ≤ CN < 16 vs. 16 ≤ CN: 2.56 vs. 3.02 vs. 4.86 (months), P=0.032). HER2 SNVs prolonged duration of PFS without statistical significance (Median PFS of HER2 SNVs vs. WT: 4.24 vs. 3.19 (months), P=0.114), but 10 of 13 BCs with HER2 SNV (76.9%) had clinical benefit from poziotinib and 5 BCs (38.5%) had durable response more than 6 months. Conclusion: In this biomarker analysis, SNV of HER2 was frequently observed in HER2 positive MBCs and HER2 CN amplification was detected not in all. High CN amplification of HER2 derived longer PFS than those with low CN. To contrary to this, activating PIK3CA mutations shorten PFS compared to those with WT. In addition, HER2 SNVs might be a potential biomarker of poziotinib in HER2-positive MBC. Further functional study would be warranted.

Citation Format: Kim J-Y, Lee E, Park K, Jung HH, Park W-Y, Lee K-H, Sohn JH, Lee KS, Jung KH, Kim J-H, Lee KH, Im S-A, Park YH. Molecular alterations and poziotinib, a pan-HER inhibitor efficacy in human epidermal growth factor receptor 2(HER2) positive breast cancers: Combined exploratory biomarker analysis from phase II clinical trial of poziotinib for refractory HER2 positive breast cancer(BC) patients [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 P2-09-21.

Abstract P5-21-13: Olaparib monotherapy versus chemotherapy for patients with HER2-negative metastatic breast cancer and a germline BRCA mutation: Asian subgroup analysis from the phase III OlympiAD trial

Background

In the Phase III OlympiAD trial (NCT02000622, D0819C00003), olaparib (Lynparza™) showed a significant progression-free survival (PFS) improvement compared with chemotherapy treatment of physician's choice (TPC) in patients (pts) with metastatic breast cancer (mBC) and a germline BRCA mutation (gBRCAm) (Robson et al. NEJM 2017). Here, we present data from a subgroup analysis of Asian pts. It is not yet known whether Asian pts, in comparison with the global patient population, may experience instances of differential toxicity with olaparib therapy.

Methods

OlympiAD, an open-label, multicenter, Phase III trial, randomized (2:1) pts with HER2-negative mBC and a gBRCAm to olaparib tablets (300 mg twice daily) or single-agent TPC (21-day cycles of capecitabine, eribulin or vinorelbine). Pts must have received ≤2 lines of chemotherapy for mBC and prior anthracycline and taxane in the adjuvant, neo-adjuvant or metastatic setting. Primary endpoint was PFS by blinded independent central review (BICR). Region (Asia, Europe, North America, South America) was a pre-defined subgroup for PFS.

Results

The Asian subgroup analysis included pts randomized at centers in China, Japan, Korea and Taiwan. Of 87 Asian pts randomized (median age 46 years), 86 received study treatment (n=59, olaparib; n=27, TPC). In the olaparib group, 29/59 (49%) had estrogen receptor positive (ER+) and/or progesterone receptor positive (PR+) tumors, and 30/59 (51%) had triple negative breast cancer (TNBC). In the TPC group, 13/28 (46%) had ER+/PR+ tumors and 15/28 (54%) had TNBC. The primary endpoint, PFS by BICR, favored olaparib with a hazard ratio (HR) of 0.53 (95% confidence interval [CI] 0.29–0.97; median 5.7 vs 4.2 months; 77% maturity), and was supported by investigator-assessed PFS (HR 0.29, 95% CI 0.16–0.55). In the overall OlympiAD study population (N=302), the PFS by BICR favored olaparib with a HR of 0.58 (95% CI 0.43–0.80; P=0.0009). Within the Asian subgroup, objective response rate (ORR) (RECIST) was 64% for olaparib versus 38% for the TPC group. Time to second progression, PFS2, was longer for pts receiving olaparib versus TPC (HR 0.43, 95% CI 0.22–0.84; 57% maturity). Grade ≥3 adverse events (AEs) occurred in 46% and 59% of pts receiving olaparib and TPC, respectively. The most common grade ≥3 AE was anemia (olaparib, 20%; TPC, 15%). In both treatment groups, 7% of pts discontinued study treatment due to AEs (n=4, olaparib; n=2, TPC). The tolerability profile of olaparib between the subgroup of Asian pts and the overall OlympiAD population will be examined in our data presentation.

Conclusion

Olaparib demonstrated an efficacy benefit compared with TPC in pts with HER2-negative mBC and a gBRCAm in this subgroup analysis of Asian pts from the Phase III OlympiAD trial. Discontinuation rates due to toxicity were low, highlighting that olaparib was generally well-tolerated. The efficacy of olaparib within the subgroup of Asian pts was consistent with that shown for the full OlympiAD dataset; consistent hazard ratios were shown in favor of olaparib using the primary endpoint of PFS by BICR, and for the key secondary endpoints of PFS by investigator assessment, PFS2, and ORR.

Citation Format: Im S-A, Xu B, Li W, Robson M, Ouyang Q, Yeh D-C, Iwata H, Park Y-H, Sohn JH, Tseng L-M, Goessl C, Wu W, Runswick S, Masuda N. Olaparib monotherapy versus chemotherapy for patients with HER2-negative metastatic breast cancer and a germline BRCA mutation: Asian subgroup analysis from the phase III OlympiAD 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 P5-21-13.

SnO2 hollow nanotubes: a novel and efficient support matrix for enzyme immobilization

A major challenge in the industrial use of enzymes is maintaining their stability at elevated temperatures and in harsh organic solvents. In order to address this issue, we investigated the use of nanotubes as a support material for the immobilization and stabilization of enzymes in this work. SnO₂ hollow nanotubes with a high surface area were synthesized by electrospinning the SnCl₂ precursor and polyvinylpyrrolidone (dissolved in dimethyl formamide and ethanol). The electrospun product was used for the covalent immobilization of enzymes such as lipase, horseradish peroxidase, and glucose oxidase. The use of SnO₂ hollow nanotubes as a support was promising for all immobilized enzymes, with lipase having the highest protein loading value of 217 mg/g, immobilization yield of 93%, and immobilization efficiency of 89%. The immobilized enzymes were fully characterized by various analytical methods. The covalently bonded lipase showed a half-life value of 4.5 h at 70 °C and retained ~91% of its original activity even after 10 repetitive cycles of use. Thus, the SnO₂ hollow nanotubes with their high surface area are promising as a support material for the immobilization of enzymes, leading to improved thermal stability and a higher residual activity of the immobilized enzyme under harsh solvent conditions, as compared to the free enzyme.

Production of Polyhydroxyalkanoates from Sludge Palm Oil Using Pseudomonas putida S12

Polyhydroxyalkanoates (PHAs) are biodegradable plastics produced by bacteria, but their use in diverse applications is prohibited by high production costs. To reduce these costs, the conversion by Pseudomonas strains of P HAs from crude s ludge p alm oil ( SPO) a s an inexpensive renewable raw material was tested. Pseudomonas putida S12 was found to produce the highest yield (~41%) of elastomeric medium-chain-length (MCL)-PHAs from SPO. The MCL-PHA characteristics were analyzed by gas-chromatography/mass spectrometry, gel permeation chromatography, and differential scanning calorimetry. These findings may contribute to more widespread use of PHAs by reducing PHA production costs.

Co-fermentation using Recombinant Saccharomyces cerevisiae Yeast Strains Hyper-secreting Different Cellulases for the Production of Cellulosic Bioethanol

To realize the economical production of ethanol and other bio-based chemicals from lignocellulosic biomass by consolidated bioprocessing (CBP), various cellulases from different sources were tested to improve the level of cellulase secretion in the yeast Saccharomyces cerevisiae by screening an optimal translational fusion partner (TFP) as both a secretion signal and fusion partner. Among them, four indispensable cellulases for cellulose hydrolysis, including Chaetomium thermophilum cellobiohydrolase (CtCBH1), Chrysosporium lucknowense cellobiohydrolase (ClCBH2), Trichoderma reesei endoglucanase (TrEGL2), and Saccharomycopsis fibuligera β-glucosidase (SfBGL1), were identified to be highly secreted in active form in yeast. Despite variability in the enzyme levels produced, each recombinant yeast could secrete approximately 0.6–2.0 g/L of cellulases into the fermentation broth. The synergistic effect of the mixed culture of the four strains expressing the essential cellulases with the insoluble substrate Avicel and several types of cellulosic biomass was demonstrated to be effective. Co-fermentation of these yeast strains produced approximately 14 g/L ethanol from the pre-treated rice straw containing 35 g/L glucan with 3-fold higher productivity than that of wild type yeast using a reduced amount of commercial cellulases. This process will contribute to the cost-effective production of bioenergy such as bioethanol and biochemicals from cellulosic biomass.

Diagnostic assessment of intraoperative cytology for papillary thyroid carcinoma: using a decision tree analysis

PURPOSE

The aim of this study was to elucidate the cytological characteristics and the diagnostic usefulness of intraoperative cytology (IOC) for papillary thyroid carcinoma (PTC). In addition, using decision tree analysis, effective features for accurate cytological diagnosis were sought.

METHODS

We investigated cellularity, cytological features and diagnosis based on the Bethesda System for Reporting Thyroid Cytopathology in IOC of 240 conventional PTCs. The cytological features were evaluated in terms of nuclear score with nuclear features, and additional figures such as presence of swirling sheets, psammoma bodies, and multinucleated giant cells. The nuclear score (range 0-7) was made via seven nuclear features, including (1) enlarged, (2) oval or irregularly shaped nuclei, (3) longitudinal nuclear grooves, (4) intranuclear cytoplasmic pseudoinclusion, (5) pale nuclei with powdery chromatin, (6) nuclear membrane thickening, and (7) marginally placed micronucleoli.

RESULTS

Nuclear scores in PTC, suspicious for malignancy, and atypia of undetermined significance cases were 6.18 ± 0.80, 4.48 ± 0.82, and 3.15 ± 0.67, respectively. Additional figures more frequent in PTC than in other diagnostic categories were identified. Cellularity of IOC significantly correlated with tumor size, nuclear score, and presence of additional figures. Also, IOCs with higher nuclear scores (4-7) significantly correlated with larger tumor size and presence of additional figures. In decision tree analysis, IOCs with nuclear score >5 and swirling sheets could be considered diagnostic for PTCs.

CONCLUSIONS

Our study suggests that IOCs using nuclear features and additional figures could be useful with decreasing the likelihood of inconclusive results.

Abstract OT1-01-12: A phase II, multicenter, randomized trial of eribulin plus gemcitabine (EG) vs. paclitaxel plus gemcitabine (PG) in patients with HER2-negative metastatic breast cancer as first-line chemotherapy

Background: Metastatic breast cancer (MBC) is an incurable disease and is needed to improve effective chemotherapy. Paclitaxel plus Gemcitabine (PG) combination chemotherapy is one of the preferred chemotherapeutic regimens for patients with MBC, and was found to be proper as a maintenance chemotherapy regimen with survival benefit and feasible toxicity profile. Eribulin mesylate is a non-taxane inhibitor of microtubule dynamics of the halichondrin class of antineoplastic drugs. A recent pooled analysis of two phase II studies with eribulin showed improved overall survival in in various patient subgroups with advanced/metastatic breast cancer who had previously received an anthracycline and a taxane. Furthermore, eribulin may have rational benefit compared with paclitaxel in terms of neurotoxicity. Therefore, Eribulin plus Gemcitabine (EG) combination chemotherapy may have less neurotoxocity comparing to PG.

Trial Design: Prospective randomized phase 2, open-label, two-arm, multi-center study comparing EG chemotherapy with PG chemotherapy for patients with HER-2 negative MBC as first-line chemotherapy.

Eligibility Criteria: Histologically confirmed breast cancer patients, at least 19 years of age, with no prior history of chemotherapy for metastatic, recurrent breast cancer with evaluable lesions (as per RECIST, 1.1) who have adequate hematologic, renal, and hepatic function. Patients either may or may not have a prior anthracycline containing regimen. Prior hormonal therapy as a treatment of metastatic disease is allowed.

Specific Aims:

The primary efficacy endpoint of the trial is Progression-Free Survival (PFS). The secondary efficacy endpoints are: Time to Treatment Failure (TTF); Overall Survival (OS); neuropathic scale (FACT for Taxane QOL assessment); toxicity; duration of response; Objective Response Rate (ORR); Clinical Benefit Rate. The exploratory endpoint of the study includes pharmacogenetic profile.

Statistical Methods:

The initial sample size of the present study was determined based on the data derived from a previous trial on PG maintenance chemotherapy design; 6-month PFS is 70% for PG chemotherapy. This design was hypothesized that EG chemotherapy would not be inferior to PG chemotherapy. Thus, estimated PFS for each arm is 70%. Based on this estimate, we would plan to recruit a total of 100 patients (50 per arm). Considering drop-out rate of 10%, total 112 MBC patients planned to be enrolled.

Present Accrual and Target Accrual:Enrollment has been completed as of March, 2016 with a target enrollment of 112 patients.

Contact information:Kyung Hae Jung MD, Ph.D. khjung@amc.seoul.kr

ClinicalTrials.gov Identifier: NCT02263495.

Citation Format: Park YH, Im S-A, Sohn JH, Lee KS, Chae YS, Lee KH, Kim J-H, Im Y-H, Ahn JS, Kim T-Y, Lee K-H, Kim S-B, Ahn J-H, Kim GM, Park IH, Lee SJ, Han HS, Kim SH, Jung KH. A phase II, multicenter, randomized trial of eribulin plus gemcitabine (EG) vs. paclitaxel plus gemcitabine (PG) in patients with HER2-negative metastatic breast cancer as first-line chemotherapy [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 OT1-01-12.

Abstract P4-22-22: Cobimetinib (C) combined with paclitaxel (P) as a first-line treatment in patients (pts) with advanced triple-negative breast cancer (COLET study): Updated clinical and biomarker results

Resistance to standard taxane-based chemotherapy is common in triple-negative breast cancer (TNBC). Mutations and gene amplifications in the MAPK pathway that upregulate MAPK signaling are present in many TNBC tumors. Upregulation of the MAPK signaling pathway can result in degradation of the pro-apoptotic protein BIM and upregulation of anti-apoptotic proteins, including BCL-2, BCL-XL, and MCL-1, thus promoting cell survival and desensitizing tumor cells to the pro-apoptotic effects of taxane chemotherapy. Updated data on clinical safety and efficacy are presented along with biomarker data evaluating the effects of treatment on induction of apoptosis.The COLET study (ClinicalTrials.gov ID, NCT02322814; EudraCT number, 2014-002230-32) consisted of a safety run-in (n∼12) followed by a blinded 1:1 randomized expansion stage (n∼90) to C + P or placebo (PBO) + P. The safety stage is complete and the randomized stage is enrolling pts. Two additional cohorts investigating the effect of adding atezolizumab will be recruiting and are out of scope of this submission. Pts in cohort I were treated with P 80 mg/m2 on days 1, 8, and 15 and C/PBO 60 mg/day on days 3–23 of each 28-day cycle until disease progression or unacceptable toxicity. Gene expression and apoptotic index were measured by RNA-Seq and TUNEL staining, respectively, to assess the biologic activity of C + P.Sixteen women (median age, 55.5 years) were enrolled in the safety run-in stage. At data snapshot (April 22, 2016), all 16 pts had received ≥1 dose of study treatment. Median time on treatment was 116 days (range, 7-336) for C and 84 days (range, 0-351) for P. Fifteen (94%) pts had ≥1 adverse event (AE); 5 (31%) pts had grade 1/2 AEs and 10 (63%) pts had grade 3 AEs (Table). No pts experienced grade 4–5 AEs. Among the 16 safety run-in patients, responses to date include partial response (PR; n = 8 [50.0%]), stable disease (SD, n = 4 [25.0%]), and progressive disease (n = 2 [12.5%]), as well as 2 pts with no post-baseline tumor assessment. Six pts maintained a PR at ∼20 weeks and three maintained a PR at ≥40 weeks. To date, matched pre- and on-treatment biopsies were evaluable for 2 pts, 1 with a PR and 1 with SD. In the patient who attained a PR, increased expression of pro-apoptosis genes, including BIM, was observed; but this was not seen in the patient experiencing SD. The PR patient also had an increase in apoptotic index. Updated biomarker data will be reported.This is the first study to evaluate C + P in TNBC. The safety profile of C + P is consistent with that of known safety profiles. Efficacy and safety will be further evaluated in the ongoing randomized stage.

Most common (any grade ≥20%) AEsTreatment-emergent AEs, n (%)C + P (safety run-in stage), N = 16 All gradesGrade 3Diarrhea10 (63)1 (6)Rash8 (50)0Nausea7 (44)0Alopecia5 (31)0Blood CPK level increase5 (31)1 (6)Stomatitis4 (25)2 (13)Asthenia4 (25)1 (6)Constipation4 (25)0Dyspnea4 (25)0Edema peripheral4 (25)0Pyrexia4 (25)0Vomiting4 (25)0AEs, adverse events; C, cobimetinib; CPK, creatinine phosphokinase; P, paclitaxel.

Citation Format: Brufsky A, Kim S-B, Velu T, García-Saenz JA, Tan-Chiu E, Sohn JH, Dirix L, Borms MV, Liu M-C, Moezi MM, Kozloff MF, Sparano JA, Xu N, Wongchenko M, Simmons B, McNally V, Miles D. Cobimetinib (C) combined with paclitaxel (P) as a first-line treatment in patients (pts) with advanced triple-negative breast cancer (COLET study): Updated clinical and biomarker results [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 P4-22-22.

Co-expression of two heterologous lactate dehydrogenases genes in Kluyveromyces marxianus for l-lactic acid production

Lactic acid (LA) is a versatile compound used in the food, pharmaceutical, textile, leather, and chemical industries. Biological production of LA is possible by yeast strains expressing a bacterial gene encoding l-lactate dehydrogenase (LDH). Kluyveromyces marxianus is an emerging non-conventional yeast with various phenotypes of industrial interest. However, it has not been extensively studied for LA production. In this study, K. marxianus was engineered to express and co-express various heterologous LDH enzymes that were reported to have different pH optimums. Specifically, three LDH enzymes originating from Staphylococcus epidermidis (SeLDH; optimal at pH 5.6), Lactobacillus acidophilus (LaLDH; optimal at pH 5.3), and Bos taurus (BtLDH; optimal at pH 9.8) were functionally expressed individually and in combination in K. marxianus, and the resulting strains were compared in terms of LA production. A strain co-expressing SeLDH and LaLDH (KM5 La+SeLDH) produced 16.0g/L LA, whereas the strains expressing those enzymes individually produced only 8.4 and 6.8g/L, respectively. This co-expressing strain produced 24.0g/L LA with a yield of 0.48g/g glucose in the presence of CaCO_3. Our results suggest that co-expression of LDH enzymes with different pH optimums provides sufficient LDH activity under dynamic intracellular pH conditions, leading to enhanced production of LA compared to individual expression of the LDH enzymes.

A novel fusion partner for enhanced secretion of recombinant proteins in Saccharomyces cerevisiae

Expressing proteins with fusion partners improves yield and simplifies the purification process. We developed a novel fusion partner to improve the secretion of heterologous proteins that are otherwise poorly excreted in yeast. The VOA1 (YGR106C) gene of Saccharomyces cerevisiae encodes a subunit of vacuolar ATPase. We found that C-terminally truncated Voa1p was highly secreted into the culture medium, even when fused with rarely secreted heterologous proteins such as human interleukin-2 (hIL-2). Deletion mapping of C-terminally truncated Voa1p, identified a hydrophilic 28-amino acid peptide (HL peptide) that was responsible for the enhanced secretion of target protein. A purification tag and a protease cleavage site were added to use HL peptide as a multi-purpose fusion partner. The utility of this system was tested via the expression and purification of various heterologous proteins. In many cases, the yield of target proteins fused with the peptide was significantly increased, and fusion proteins could be directly purified with affinity chromatography. The fusion partner was removed by in vitro processing, and intact proteins were purified by re-application of samples to affinity chromatography.

Overall accuracy of cervical cytology and clinicopathological significance of LSIL cells in ASC-H cytology

OBJECTIVE

The aims of this study were (i) to investigate the diagnostic accuracy of Papanicolaou (Pap) smears and (ii) to evaluate the clinicopathological significance of the presence of low-grade squamous intraepithelial lesion (LSIL) cells in atypical squamous cells cannot exclude high-grade squamous intraepithelial lesion (HSIL) (ASC-H) cytology.

METHODS

We retrospectively reviewed paired cytological and histological findings from 3141 patients. ASC-H cytology was classified as either ASC-H or LSIL with some features suggestive of the presence of a concurrent HSIL (LSIL-H). Clinicopathological characteristics were evaluated through a retrospective study and meta-analysis.

RESULTS

The accuracy of the cytological diagnosis was 93.7% (2942 of 3141 cases). The positive predictive value (PPV) of ASC-H for cervical intraepithelial neoplasia grade 2 or worse (CIN 2+ ) was 51.4%. In cases of LSIL-H, CIN 2+ histology was more prevalent in the pre-menopausal period (19-44 years) than in peri- and postmenopausal periods (older than 45 years) (P = 0.024). There was no difference in the ability of LSIL-H and ASC-H to predict CIN 2+.

CONCLUSION

The Pap smear is a good cervical cancer screening method. Although there was no difference in the predictive value for CIN 2+ between LSIL-H and ASC-H, the presence of definite LSIL cells was more predictive of CIN 2+ in younger patients than in older patients.

Abstract P1-09-09: Role of endocrine therapy in premenopausal patients with hormone receptor-positive metastatic breast cancer, compared with postmenopausal patients: Diachronic analyses from nationwide cohort in Korea (KCSG BR 14-07)

Background

Endocrine therapy (E) has a major role in treatment of hormone receptor (HR)-positive metastatic breast cancer (MBC). However, in contrast to western countries, premenopausal patients (PRE) more prevalent (50% of all breast cancer patients) and have less options of E than postmenopausal patients (POST) in Korea where the use of LHRH agonist in combination aromatase inhibitors (AIs) in PRE is restricted. Recently we have been successfully established nationwide cohort for the patients MBC (575 patients from 26 institutes). This study was designed to evaluate the role of E especially in PRE.

Methods

The patients with MBC were prospectively or retrospectively enrolled between September 2014 and May 2015. Only menopausal status-confirmed patients (296) were analyzed. Postmenopause was defined, based on NCCN guideline. Total duration of treatment was defined as the time from start day of any first treatment to end of any last treatment. Total duration of E was defined as the sum of time duration of each E. Overall survival was calculated from the start day of any treatment for MBC to any causes of death. This work is supported by National Strategic Coordinating Center for Clinical Research (H110C2020).

Results

A total of 296 patients with HR-positive MBC were analyzed [PRE, 169 (57.1%) and POST, 127 (42.9%)]. Except age (mean 44 and 60 years), baseline characteristics including in pathology, HER2 status, initial pathologic stage, de novo metastasis versus recurrence, surgery and adjuvant treatment (chemotherapy, endocrine therapy and radiotherapy) were well balanced. 92 (54.4%) of PRE and 77 (60.6%) of POST received at least one or more E through all treatment course. 41 (24.2%) of PRE and 44 (34.6%) received E as 1st-line treatment (p=0.034). Among PRE who received 1st-line of E, 30 (71.4%) and 9 (21.4%) of PRE received 2nd- and 3rd-line E. 20 (45.4%) and 10 (22.7%) of POST received 2nd- and 3rd- or more line of E. Most of PRE (54%) received tamoxifen+/-goserelin and 32% of PRE received AIs along with ovarian suppression. 71% of POST received AIs. As initial treatment, E was more frequently used in POST than in PRE (34.6% and 24.3%, p=0.053). Overall survival (OS) of all patients was 18.2 months (95% CI, 14.8-21.5). There was no difference in OS between PRE (17.8 months, 10.9-24.8) and POST (18.5 months, 95% CI, 13.2-23.9) (P=0.337). No difference of OS was observed (E, 18.1 moths, 95% CI, 13.0-23.3; chemotherapy 21.2 moths, 95% CI, 16.8-25.5), regardless of initial treatment. Total duration of treatment of PRE and POST were 15.2 and 13.6 months, respectively with no significant difference (p=0.389). PRE (8.3 moths, 95% CI,5.7-10.8) showed the trend toward longer duration of E in comparison with POST (5.5 moths, 95% CI,4.4-6.7), however the difference did not reach statistical significance (p=0.051).

Conclusion

E was more commonly used as 1st-line therapy in POST than in PRE. Although PRE had limited options of E, E was used in long duration of treatment especially in PRE. These findings suggested that E had a role in treatment for PRE with HR-positive MBC and could be used in treatment for PRE with good efficacy.

Citation Format: Kim T-Y, Ahn J-H, Yoon JH, Sohn JH, Kim GM, Lee KH, Park YH, Koh S-J, Lee SE, Chae Y, Lee KS, Lee KE, Won HS, Kim JH, Jeong J, Park KH, Cho EK, Im Y-H, Im S-A, Jung KH. Role of endocrine therapy in premenopausal patients with hormone receptor-positive metastatic breast cancer, compared with postmenopausal patients: Diachronic analyses from nationwide cohort in Korea (KCSG BR 14-07). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-09-09.

Abstract P1-15-04: Irriversible chemotherapy-induced alopecia in breast cancer patient

Introduction

Patients with breast cancer who received chemotherapy have distressing side effects such as mucositis, alopecia, gastritis, and BM suppression. Chemotherapy-induced alopecia(CIA) is one of considerable psychological events in self-esteem in patients with breast cancer, but the possibility of irreversible alopecia is often overlooked by physician.

We investigated clinical characteristics of CIA and prevalence of irreversible severe hair loss in patient with breast cancer who received chemotherapy.

Methods

We conducted a survey to collect demographic information about CIA with 150 breast cancer patients who had passed at least 6 months since their last day of chemotherapy from February 2015 to May 2015 in Yonsei Cancer Center. We obtained clinical information as age, elapsed time from end of chemotherapy, chemotherapy regimen, and other adjuvant therapy using their electrical medical records. We compared irreversible CIA characters between anthracycline and cyclophosphamide (AC) and taxane based regimen groups. The severe alopecia was defined as the hair density loss over 50% compared to the hair density before chemotherapy.

Results

The mean age at chemotherapy was 48 years old (±17.3) and the mean elapsed time after chemotherapy was 37 months (±9.5) in total patients.

Remnant alopecia was reported in 71 patients (47.3%). Wig or hat were used in 39 patients (26.0%).

The mean satisfaction score with a five-point scale was 4 in patients without alopecia or hair character change and 2.2 in patients with irreversible alopecia (p<0.001). The severe irreversible hair loss was complained by the 12 (8.2%) patients.

AC and taxane based chemotherapy were carried out in 65 and 85 patients, respectively. In AC group, remnant alopecia was shown in 18 patients (27.7%), and more than a half of patients in taxane group, 53 patients (62.4%), showed remnant alopecia (p<0.001). While only five patients (7.8%) in AC group suffered for severe hair loss, 26 patients (31.3%) in taxane group were affected by severe hair loss (p=0.001). The mean satisfaction level of hair status in patients in taxane group was 2.5 as compared to 3.6 in those in AC group (p<0.001).

Conclusion

Contrary to general expectation, About a half of breast cancer patients who received chemotherapy complained of irreversible hair loss even though at least 6 months has elapsed since the end of chemotherpy. In particular, patients with taxane based chemotherapy had more irreversible and severe alopecia than those with AC chemotherapy.

Citation Format: Kim S, Park HS, Kim JY, Nam S, Kim GM, Sohn JH, Kim SI. Irriversible chemotherapy-induced alopecia in breast cancer patient. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-15-04.

Abstract P6-10-03: Does participation in clinical trials influence on survival in patients with metastatic breast cancer?

Background

Recently, many clinical trials (TRIAL) especially incorporated with molecular-targeted agents are being conducted in treatment for breast cancer worldwide. However, the relation of participating clinical trials with survival has not been actively studied. This study was designed to evaluate whether participation in clinical trials could improve overall survival (OS) or not in patients with metastatic breast cancer (MBC), compared with conventional treatment.

Method

Korean Cancer Study Group (KCSG) has successfully established Nationwide Cohort in KOREA to conduct diachronic analysis (KCSG BR 14-07). Clinical data for patients with MBC were collected from this Cohort. OS was defined as the time duration from first diagnosis of metastasis to any cause of death. This work is supported by National Strategic Coordinating Center for Clinical Research (H110C2020).

Results

A total of 575 patients with metastatic breast from 26 institutes in KOREA cancer MBC were consequently enrolled between September 2014 and May 2015. 156 (27.1%) of patients were enrolled to at least one or more clinical trials and 419 patients received only conventional treatment (CONV). Age, hormone status, HER2 status, initial pathologic stage, metastasis versus recurrence, adjuvant treatment, ECOG performance status (PS) (0, 1 vs 2 or more) were similar between TRIAL and CONV. 30% of trials were associated with HER2-targeted agents. As initial treatment, chemotherapy was more frequently used in TRIAL (85.9%) than in CONV (79.0%) (P=0.038). Number of regimens of chemotherapy was greater in TRIAL (2.9+/-1.8) than CONV (2.1+/-1.6) (P<0.001). Number of regimens of endocrine therapy (E) was similar between TRIAL (1.4+/-0.6) and CONV (1.5+/-0.7) (P=0.474). Overall survival of all patients was 16.2 months (95% CI, 14.1-18.1). TRIAL showed significant prolongation of survival, compared with CONV [21.1 (95% CI, 17.7-24.6) vs 15.1 months (95% CI, 13.1-17.2); P=0.005]. The differences in OS was constantly observed in HER2-positive [23.8 (16.7-30.9) vs 17.2 months (95% CI, 12.4-21.9); P=0.018] and Triple-negative [15.4 (10.5-20.3) vs 12.0 months (95% CI, 10.2-13.8); P=0.025]. In multivariate analysis, initial metastasis, hormone status, ECOG PS did not influence on OS between TRIAL and CONV (P=0.849)

Conclusion

Participating in clinical trials could be associated with prolongation of survival. This results constantly maintained in HER2-positive and triple-negative MBC. These findings suggested that clinical trials are useful for the patients with MBC, even if the patients do not complete the standard treatment.

Citation Format: Kim T-Y, Sohn JH, Kim S-B, Yoon JH, Kim GM, Lee KH, Koh S-J, Park YH, Lee SE, Chae Y, Lee KS, Lee KE, Won HS, Kim JH, Jeong J, Park KH, Cho EK, Im Y-H, Im S-A, Jung KH. Does participation in clinical trials influence on survival in patients with metastatic breast cancer?. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-10-03.

Abstract OT3-01-10: A prospective, open-label, single-arm, multi-center, phase II exploratory study to evaluate the efficacy and safety of poziotinib (NOV120101) in patients with HER2-positive metastatic breast cancer who have received at least two prior HER2-directed regimens

Background: Poziotinib is a novel, oral, irreversible pan-HER inhibitor that has shown promising clinical activity in Phase 1 studies of patients (pts) with advance HER2 positive breast cancer who have failed at least 2 prior lines of HER2-directed therapy. A Phase 2 study of poziotinib was initiated in Korea in March 2015 in pts with HER2+ metastatic breast cancer. This phase 2 study is designed to seek accelerated approval for poziotinib for the treatment of metastatic breast cancer in Korea.

Trial Design: Prospective Phase 2, open-label, single-arm, multi-center study in pts with recurrent, Stage IV breast cancer with HER2-overexpression who had received at least 2 prior HER2-directed regimens

Eligibility Criteria: Histologically confirmed breast cancer patients, at least 19 years of age, with confirmed HER2 positive evaluable tumors (per RECIST, 1.1) who have adequate hematologic, renal, and hepatic function and have failed at least two HER2-directed regimens that included a taxane-containing anticancer chemotherapy, with a life expectancy of at least 12 weeks.

Specific Aims: The Primary Efficacy Endpoint of the study was Progression-Free Survival (PFS). The Secondary Efficacy Endpoints included: PFS rate at 12 weeks post-dose; Objective Response Rate (ORR) including Complete Response (CR) and Partial Response (PR) rates; Disease Control Rate (DCR) including CR, PR, and Stable Disease (SD); Duration of Disease Control; Overall Survival (OS); Time to Progression (TTP); Time to Objective Response and Duration of Objective Response. The Exploratory Endpoints included: Population Pharmacokinetic (PK) Profile and Exploratory Genomic and Biomarker Analyses.

Statistical Methods: In the randomized, multicenter, 2-arm, open-label study of trastuzumab emtansine (TH3RESA18), the median PFS was shown to be 3.3 months in subjects with optimal treatment per Investigator's Choice. This ongoing study with poziotinib expects a median PFS of 4.5 months based on data from a previous Phase 1 study of poziotinib (NOV120101). Based on the following assumptions, a 5% one-sided significance level, and 80% power, and 2 months of accrual and 12 months of follow-up, 66 subjects will be required. Accounting for a 10% drop-out rate, a total of 74 subjects will be recruited into this ongoing Phase 2 study.

Present Accrual and Target Accrual: 17 patients enrolled as of May 20, 2015 with a total target enrollment of 74 patients

Contact information:

ClinicalTrials.gov Identifier: NCT02418689.

Citation Format: Park Y-H, Jung KH, Sohn JH, Lee KS, Lee KH, Kim J-H, Kim J-Y, Jung J, Han H, Park W-Y, Im S-A. A prospective, open-label, single-arm, multi-center, phase II exploratory study to evaluate the efficacy and safety of poziotinib (NOV120101) in patients with HER2-positive metastatic breast cancer who have received at least two prior HER2-directed regimens. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT3-01-10.

Efficacy of Pre- and Postoperative Chemotherapy in Patients with Osteosarcoma of the Extremities

PURPOSE

We evaluated the treatment efficacy including survival and recurrence, and factors associated with recurrence in osteosarcoma patients treated with preoperative chemotherapy, surgery, and adjuvant chemotherapy.

MATERIALS AND METHODS

Forty nine patients with osteosarcoma were treated with preoperative chemotherapy with intra-arterial cisplatin and adriamycin infusion for 3 cycles, followed by surgery. According to the pathologic response, if tumor was necrotized more than 90%, the same adjuvant chemotherapy was reintroduced for 3 cycles, and if the response was not enough, then the salvage regimen was introduced. Plain chest film and chest CT scan were taken monthly and every 3 months, respectively. When tumor recurred, the metastasectomy was performed whenever possible.

RESULTS

Forty three patients were evaluable with amedian follow up of 53 months. Five-year disease-free and overallsurvival rate was 47.0% and 66.9%, respectively. The recurrence was observed in 22 patients (51.2%) with median time of 12.5 months. Baseline alkaline phosphatase (ALP) was the only significant factor for recurrence (p=0.03) and the patients with the possibility of metastasectomy recurrence showed higher post-relapse survival compared to other treatment modalities (26 momths vs 5~12 months).

CONCLUSION

These results indicates that pre- and postoperative chemotherapy with intra-arterial cisplatin and adriamycin infusion showed comparable treatment efficacy and acceptable toxicities.

An Efficient Genome-Wide Fusion Partner Screening System for Secretion of Recombinant Proteins in Yeast

To produce rarely secreted recombinant proteins in the yeast Saccharomyces cerevisiae, we developed a novel genome-wide optimal translational fusion partner (TFP) screening system that involves recruitment of an optimal secretion signal and fusion partner. A TFP library was constructed from a genomic and truncated cDNA library by using the invertase-based signal sequence trap technique. The efficiency of the system was demonstrated using two rarely secreted proteins, human interleukin (hIL)-2 and hIL-32. Optimal TFPs for secretion of hIL-2 and hIL-32 were easily selected, yielding secretion of these proteins up to hundreds of mg/L. Moreover, numerous uncovered yeast secretion signals and fusion partners were identified, leading to efficient secretion of various recombinant proteins. Selected TFPs were found to be useful for the hypersecretion of other recombinant proteins at yields of up to several g/L. This screening technique could provide new methods for the production of various types of difficult-to-express proteins.

Extraocular muscle injury during endoscopic sinus surgery: a series of 10 cases at a single center

BACKGROUND

Extraocular muscle (EOM) injury is a rare but serious complication of endoscopic sinus surgery (ESS). The aim of this study is to describe the clinical characteristics and course of EOM injury occurring during ESS.

DESIGN

Retrospective case series.

METHODS

Medical records and CT images of patients who suffered from EOM injury after ESS between 2006 and 2012 were retrospectively reviewed. Patient demographics, endoscopic anatomy, type of surgery (primary or revision), predisposing risk factors, site and extent of injury on CT imaging, and associated complications were evaluated. In addition, data regarding ophthalmologic management and clinical outcomes were collected.

RESULTS

Ten patients with EOM injuries after ESS were included in this study. One patient was undergoing revision ESS. All patients sustained medial rectus muscle injury and one patient suffered concurrent ipsilateral inferior rectus muscle injury. A microdebrider was used in nine cases. Right-sided injury (90% of patients) was more prevalent than left-sided injury, and 70% of injured medial rectus muscles were completely transected. After subsequent strabismus surgery, 8/9 patients regained binocular single vision in primary gaze despite residual diplopia in some gaze positions.

CONCLUSION

Although proper ophthalmologic surgery after EOM injury may improve deviation in the primary gaze position, none of the patients regained normal EOM movement. Therefore, prevention of this complication through adequate surgical technique and precautions is important.

Relative adrenal insufficiency in chronic liver disease: its prevalence and effects on long-term mortality

BACKGROUND

The relationship between relative adrenal insufficiency (RAI) and chronic liver disease is unclear.

AIM

To determine the frequency with which RAI is observed in noncritically ill patients at various stages of chronic liver disease, and the correlation between RAI and disease severity and long-term mortality.

METHODS

In total, 71 non-critically ill patients with liver cirrhosis (n = 54) and chronic hepatitis (n = 17) were evaluated prospectively. A short stimulation test (SST) with 250 μg of corticotrophin was performed to detect RAI. RAI was defined as an increase in serum cortisol of <9 μg/dL in patients with a basal total cortisol of <35 μg/dL.

RESULTS

RAI was observed in only 13 (24.1%) of 54 patients with cirrhosis. Compared to those without RAI, cirrhotic patients with RAI had significantly higher Child-Turcotte-Pugh score (10.3 ± 1.7 vs. 7.1 ± 1.8, mean ± s.d., P < 0.001) and Model for End-Stage Liver Disease score (14.5 ± 6.6 vs. 9.4 ± 3.7, P = 0.017). The cortisol response to corticotropin was negatively correlated with the severity of cirrhosis (P < 0.05). In addition, the mortality rate was higher in cirrhotic patients with RAI (69.2%) than in those without RAI (4.9%; P < 0.001) during the follow-up period of 20.1 ± 13.5 months (range, 5.8-51.1 months). The cumulative 1-year survival rates in cirrhotic patients with and without RAI were 69.2% and 95.0%, respectively (P = 0.05), while the corresponding cumulative 3-year survival rates were 0% and 95.0% (P < 0.001).

CONCLUSIONS

Relative adrenal insufficiency is more commonly observed in those with severe cirrhosis, and is clearly associated with more advanced liver disease and a shortened long-term survival. This suggests that relative adrenal insufficiency is an independent prognostic factor in non-critically ill patients with cirrhosis.

Clinical impact of microscopic extrathyroidal extension in patients with papillary thyroid microcarcinoma treated with hemithyroidectomy

BACKGROUND

Pathologically confirmed microscopic extrathyroidal extension (ETE) is often identified after hemithyroidectomy in patients with papillary thyroid microcarcinoma (PTMC). Without the presence of microscopic ETE, these patients would be optimal candidates for hemithyroidectomy.

AIM

The present study aimed at evaluating the clinical impact of microscopic ETE on the recurrence of PTMC treated with hemithyroidectomy.

SUBJECTS AND METHODS

We compared the clinicopathological characteristics and 5-year outcomes for 262 PTMC patients without ETE and 86 with microscopic ETE who were treated with hemithyroidectomy between January 2004 and December 2010.

RESULTS

The mean tumour size was larger (0.67 vs. 0.54 cm, p < 0.001) and the proportion of tumours measuring ≥0.5 cm was higher (84.9 vs. 66.8 %, p = 0.001) in patients with microscopic ETE as compared with patients without ETE. Occult multifocal disease was more frequent in patients with microscopic ETE than in those without ETE (14.0 vs. 6.5 %, p = 0.030). However, the recurrence rate was not different between the two groups during the mean 55.8-month follow-up period. In addition, univariate and multivariate analyses revealed no meaningful association between recurrence and microscopic ETE in patients with PTMC treated with hemithyroidectomy.

CONCLUSIONS

Although microscopic ETE was associated with large tumour size and multifocal disease, its clinical impact on disease recurrence was not significant in PTMC patients treated with hemithyroidectomy. Therefore, microscopic ETE identified after hemithyroidectomy would not be an absolute indication for completion thyroidectomy in patients with PTMC.

Characterization of a squalene synthase from the thraustochytrid microalga Aurantiochytrium sp. KRS101

The gene encoding squalene synthase (SQS) of the lipidproducing heterotrophic microalga Aurantiochytrium sp. KRS101 was cloned and characterized. The krsSQS gene is 1,551 bp in length and has two exons and one intron. The open reading frame of the gene is 1,164 bp in length, yielding a polypeptide of 387 predicted amino acid residues with a molecular mass of 42.7 kDa. The deduced krsSQS sequence shares at least four conserved regions known to be required for SQS enzymatic activity in other species. The protein, tagged with His6, was expressed into soluble form in Escherichia coli. The purified protein catalyzed the conversion of farnesyl diphosphate to squalene in the presence of NADPH and Mg(2+). This is the first report on the characterization of an SQS from a Thraustochytrid microalga.

A randomized, multi-center, open-label, phase II study of once-per-cycle DA-3031, a biosimilar pegylated G-CSF, compared with daily filgrastim in patients receiving TAC chemotherapy for early-stage breast cancer

BACKGROUNDS

A pegylated form of recombinant granulocyte-colony stimulating factor (G-CSF) was developed for prophylactic use in breast cancer. The aim of this study was to evaluate the efficacy and safety of once-per-cycle DA-3031 in patients receiving chemotherapy for breast cancer.

METHODS

A total of 61 patients receiving docetaxel, doxorubicin, and cyclophosphamide (TAC) chemotherapy were randomized in cycle 1 to receive daily injections of filgrastim (100 μg/m(2)) or a single subcutaneous injection of pegylated filgrastim DA-3031 at a dose of either 3.6 mg or 6 mg.

RESULTS

The mean duration of grade 4 neutropenia in cycle 1 was comparable among the treatment groups (2.48, 2.20, and 2.05 days for filgrastim, DA-3031 3.6 mg and 6 mg, respectively; P=0.275). No statistically significant differences were observed in the incidence of febrile neutropenia between the treatment groups (9.5 %, 15.0 %, and 5.0 % for filgrastim, DA-3031 3.6 mg and 6 mg, respectively; P=0.681) in cycle 1. The incidences of adverse events attributable to G-CSF were similar among the treatment groups.

CONCLUSIONS

Fixed doses of 3.6 mg or 6 mg DA-3031 have an efficacy comparable to that of daily injections of filgrastim in ameliorating grade 4 neutropenia in patients receiving TAC chemotherapy.