Review on the clinical use of eribulin mesylate for the treatment of breast cancer

Pharmacogenetics of taxane-induced neurotoxicity in breast cancer: Systematic review and meta-analysis

Taxane-based chemotherapy regimens are used as first-line treatment for breast cancer. Neurotoxicity, mainly taxane-induced peripheral neuropathy (TIPN), remains the most important dose-limiting adverse event. Multiple genes may be associated with TIPN; however, the strength and direction of the association remain unclear. For this reason, we systematically reviewed observational studies of TIPN pharmacogenetic markers in breast cancer treatment. We conducted a systematic search of terms alluding to breast cancer, genetic markers, taxanes, and neurotoxicity in Ovid, ProQuest, PubMed, Scopus, Virtual Health, and Web of Science. We assessed the quality of evidence and bias profile. We extracted relevant variables and effect measures. Whenever possible, we performed random-effects gene meta-analyses and examined interstudy heterogeneity with meta-regression models and subgroup analyses. This study follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and STrengthening the REporting of Genetic Association Studies (STREGA) reporting guidance. A total of 42 studies with 19,431 participants were included. These evaluated 262 single-nucleotide polymorphisms (SNPs) across 121 genes. We conducted meta-analyses on 23 genes with 60 SNPs (19 studies and 6246 participants). Thirteen individual SNPs (ABCB1-rs2032582, ABCB1-rs3213619, BCL6/-rs1903216, /CAND1-rs17781082, CYP1B1-rs1056836, CYP2C8-rs10509681, CYP2C8-rs11572080, EPHA5-rs7349683, EPHA6-rs301927, FZD3-rs7001034, GSTP1-rs1138272, TUBB2A-rs9501929, and XKR4-rs4737264) and the overall SNPs' effect in four genes (CYP3A4, EphA5, GSTP1, and SLCO1B1) were statistically significantly associated with TIPN through meta-analysis. In conclusion, through systematic review and meta-analysis, we found that polymorphisms, and particularly 13 SNPs, are associated with TIPN, suggesting that genetics does play a role in interindividual predisposition. Further studies could potentially use these findings to develop individual risk profiles and guide decision making.

Promising antiparasitic agents from marine sponges

Parasitic diseases especially those prevail in tropical and subtropical regions severely threaten the lives of people due to available drugs found to be ineffective as several resistant strains have been emerged. Due to the complexity of the marine environment, researchers considered it as a new field to search for compounds with therapeutic efficacy, marine sponges represents the milestone in the discovery of unique compounds of potent activities against parasitic infections. In the present article, literatures published from 2010 until March 2021 were screened to review antiparasitic potency of bioactive compounds extracted from marine sponges. 45 different genera of sponges have been studied for their antiparasitic activities. The antiparasitic activity of the crude extract or the compounds that have been isolated from marine sponges were assayed in vitro against Plasmodium falciparum, P. berghei, Trypanosoma brucei rhodesiense, T. b. brucei, T. cruzi, Leishmania donovani, L. tropica, L. infantum, L. amazonesis, L. major, L. panamesis, Haemonchus contortus and Schistosoma mansoni. The majority of antiparastic compounds extracted from marine sponges were related to alkaloids and peroxides represent the second important group of antiparasitic compounds extracted from sponges followed by terpenoids. Some substances have been extracted and used as antiparasitic agents to a lesser extent like steroids, amino acids, lipids, polysaccharides and isonitriles. The activities of these isolated compounds against parasites were screened using in vitro techniques. Compounds' potent activity in screened papers was classified in three categories according to IC₅₀: low active or inactive, moderately active and good potent active.

Biomaterials from the sea: Future building blocks for biomedical applications

Marine resources have tremendous potential for developing high-value biomaterials. The last decade has seen an increasing number of biomaterials that originate from marine organisms. This field is rapidly evolving. Marine biomaterials experience several periods of discovery and development ranging from coralline bone graft to polysaccharide-based biomaterials. The latter are represented by chitin and chitosan, marine-derived collagen, and composites of different organisms of marine origin. The diversity of marine natural products, their properties and applications are discussed thoroughly in the present review. These materials are easily available and possess excellent biocompatibility, biodegradability and potent bioactive characteristics. Important applications of marine biomaterials include medical applications, antimicrobial agents, drug delivery agents, anticoagulants, rehabilitation of diseases such as cardiovascular diseases, bone diseases and diabetes, as well as comestible, cosmetic and industrial applications.

The drebrin/EB3 pathway regulates cytoskeletal dynamics to drive neuritogenesis in embryonic cortical neurons

Co-ordinating the dynamic behaviour of actin filaments (F-actin) and microtubules in filopodia is an important underlying process in neuritogenesis, but the molecular pathways involved are ill-defined. The drebrin/end-binding protein 3 (EB3) pathway is a candidate pathway for linking F-actin to microtubules in filopodia. Drebrin binds F-actin and, simultaneously, the microtubule-binding protein EB3 when bound to microtubule plus-ends. We assessed the effect on neuritogenesis of gain- or loss-of-function of proteins in the drebrin/EB3 pathway in rat embryonic cortical neurons in culture. Loss-of-function of drebrin by gene editing or pharmacological inhibition of drebrin binding to F-actin reduced the number of dynamic microtubules in the cell periphery and simultaneously delayed the initiation of neuritogenesis, whereas over-expression of drebrin induced supernumerary neurites. Similarly, loss of EB3 inhibited neuritogenesis, whereas loss of end-binding protein 1 (EB1), a related protein that does not bind to drebrin, did not affect neuritogenesis. Over-expression of EB3, but not EB1, induced supernumerary neurites. We discovered that EB3 is more proximally located at dynamic microtubule plus-ends than EB1 in growth cone filopodia allowing for continuous microtubule elongation as the drebrin/EB3 pathway zippers microtubules to F-actin in filopodia. Finally, we showed that preventing the entry of dynamic microtubules into filopodia using a pharmacological inhibitor of microtubule dynamics is associated with a loss of EB3, but not EB1, from microtubule plus-ends and a concurrent attenuation of neuritogenesis. Collectively, these findings support the idea that neuritogenesis depends on microtubule/F-actin zippering in filopodia orchestrated by the drebrin/EB3 pathway.

Real-world effectiveness of eribulin in heavily pretreated patients with metastatic breast cancer in China: a multicenter retrospective study

Background:

Eribulin is a nontaxane microtubule inhibitor approved in China for patients with advanced breast cancer who show progression after ⩾2 lines of chemotherapy. The aim of this study was to determine the efficacy and safety profile of eribulin and explore potential predictive factors for the efficacy of eribulin among Chinese women with metastatic breast cancer (MBC) in real-world practice.

Patients and Methods:

A total of 272 consecutive MBC patients who were treated with eribulin between November 2019 and October 2020 in 9 institutions nationwide were included in this study. Eribulin was administered intravenously at a dose of 1.4 mg/m² on days 1 and 8 of a 21-day cycle. Efficacy outcomes included progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and clinical benefit rate (CBR). Adverse events (AEs) were graded according to The National Cancer Institute Common Toxicity Criteria (NCI-CTC) version 5.0.

Results:

Eribulin showed a median PFS of 4.1 months (95% confidence interval [CI] 3.6–4.6); however, the OS data were immature. The ORR was 17.6% and the CBR was 24.6%. A total of 51.8% of patients received eribulin monotherapy, while 48.2% of patients were treated with eribulin plus targeted therapy or other chemotherapy. The number of metastatic sites, duration of previous taxane treatment for MBC, and combination with bevacizumab were significant in Cox multivariate analysis (p = 0.023, p = 0.048, and p = 0.046, respectively) and were significantly associated with PFS of eribulin. The most common AEs with eribulin treatment were hematological toxicities, including neutropenia, leukopenia, and anemia.

Conclusion:

Eribulin was effective with a manageable toxicity profile in clinical practice. Furthermore, when prescribed in combination with other agents, eribulin did not increase the toxic effects of each agent. Eribulin monotherapy or plus other agents is an alternative for the heavily pretreated patients with MBC.

A critical review on marine serine protease and its inhibitors: A new wave of drugs?

Marine organisms are rich sources of enzymes and their inhibitors having enormous therapeutic potential. Among different proteolytic enzymes, serine proteases, which can be obtained from various marine organisms show a potential to biomedical application as thrombolytic agents. Although this type of proteases plays a crucial role in almost all biological processes, their uncontrolled activity often leads to several diseases. Accordingly, the actions of these types of proteases are regulated by serine protease inhibitors (SPIs). Marine SPIs control complement activation and various other physiological functions, such as inflammation, immune function, fibrinolysis, blood clotting, and cancer metastasis. This review highlights the potential use of serine proteases and their inhibitors as the new wave of promising drugs.

Systematic review of Real-World effectiveness of eribulin for locally advanced or metastatic breast cancer

BACKGROUND

Eribulin mesylate (eribulin) is indicated for patients with metastatic breast cancer (MBC) who have previously received at least two chemotherapies in the US and for patients with locally advanced breast cancer (LABC) or MBC who have progressed after at least one chemotherapy in the European Union (EU). In both indications, prior therapy should include an anthracycline and a taxane in adjuvant or metastatic setting. Numerous studies evaluated eribulin in real-world (RW) breast cancer populations to reinforce its consistent effectiveness beyond registration randomized controlled trials (RCTs) that reported median overall survival (OS) of 13.1 and 15.9 months. In this systematic literature review (SLR), we summarize the cumulative evidence on eribulin's RW effectiveness in LABC/MBC.

METHODS

We searched through Medline/PubMed and Embase databases between 2012 and 2019 for articles reporting RW eribulin use in the second- or third-line or later LABC/MBC setting. Because eribulin showed greatest OS benefits in triple negative breast cancer (TNBC) in RCTs, we also reviewed this tumor subtype. OS and progression-free survival (PFS) were the effectiveness outcomes of interest.

RESULTS

Overall, 34 journal articles or abstracts met the selection criteria. Median OS ranged between 6.9 and 28.0 months; median PFS varied from 2.3 to 14.7 months. Eight studies reported OS outcomes for TNBC patients, and median OS ranged between 3.0 and 23.0 months.

CONCLUSION

The SLR showed high variability in OS and to a lesser extent in PFS associated with eribulin use in RW setting. Despite heterogeneity in line of use and patient subtypes, this SLR supports effectiveness of eribulin for LABC/MBC in clinical practice.

Synthesis, Biological Evaluation, and Molecular Docking of Arylpyridines as Antiproliferative Agent Targeting Tubulin

Mimicking different pharmacophoric units into one scaffold is a promising structural modification tool to design new drugs with enhanced biological properties. To continue our research on the tubulin inhibitors, the synthesis and biological evaluation of arylpyridine derivatives (9-29) are described herein. Among these compounds, 6-arylpyridines (13-23) bearing benzo[d]imidazole side chains at the 2-position of pyridine ring displayed selective antiproliferative activities against HT-29 cells. More interestingly, 2-trimethoxyphenylpyridines 25, 27, and 29 bearing benzo[d]imidazole and benzo[d]oxazole side chains displayed more broad-spectrum antitumor activities against all tested cancer cell lines. 29 bearing a 6-methoxybenzo[d]oxazole group exhibited comparable activities against A549 and U251 cells to combretastatin A-4 (CA-4) and lower cytotoxicities than CA-4 and 5-Fu. Further investigations revealed 29 displays strong tubulin polymerization inhibitory activity (IC₅₀ = 2.1 μM) and effectively binds at the colchicine binding site and arrests the cell cycle of A549 in the G2/M phase by disrupting the microtubules network.

Highlights of marine natural products having parallel scaffolds found from marine-derived bacteria, sponges, and tunicates

Marine-derived bacteria are a prolific source of a wide range of structurally diverse natural products. This review, dedicated to Professor William Fenical, begins by showcasing many seminal discoveries made at the University of California San Diego from marine-derived actinomycetes. Discussed early on is the 20-year journey of discovery and advancement of the seminal actinomycetes natural product salinosporamide A into Phase III anticancer clinical trials. There are many fascinating parallels discussed that were gleaned from the comparative literature of marine sponge, tunicate, and bacteria-derived natural products. Identifying bacterial biosynthetic machinery housed in sponge and tunicate holobionts through both culture-independent and culture-dependent approaches is another important and expanding subject that is analyzed. Work reviewed herein also evaluates the hypotheses that many marine invertebrate-derived natural products are biosynthesised by associated or symbiotic bacteria. The insights and outcomes from metagenomic sequencing and synthetic biology to expand molecule discovery continue to provide exciting outcomes and they are predicted to be the source of the next generation of novel marine natural product chemical scaffolds.

Screening Marine Natural Products for New Drug Leads against Trypanosomatids and Malaria

Neglected Tropical Diseases (NTD) represent a serious threat to humans, especially for those living in poor or developing countries. Almost one-sixth of the world population is at risk of suffering from these diseases and many thousands die because of NTDs, to which we should add the sanitary, labor and social issues that hinder the economic development of these countries. Protozoan-borne diseases are responsible for more than one million deaths every year. Visceral leishmaniasis, Chagas disease or sleeping sickness are among the most lethal NTDs. Despite not being considered an NTD by the World Health Organization (WHO), malaria must be added to this sinister group. Malaria, caused by the apicomplexan parasite Plasmodium falciparum, is responsible for thousands of deaths each year. The treatment of this disease has been losing effectiveness year after year. Many of the medicines currently in use are obsolete due to their gradual loss of efficacy, their intrinsic toxicity and the emergence of drug resistance or a lack of adherence to treatment. Therefore, there is an urgent and global need for new drugs. Despite this, the scant interest shown by most of the stakeholders involved in the pharmaceutical industry makes our present therapeutic arsenal scarce, and until recently, the search for new drugs has not been seriously addressed. The sources of new drugs for these and other pathologies include natural products, synthetic molecules or repurposing drugs. The most frequent sources of natural products are microorganisms, e.g., bacteria, fungi, yeasts, algae and plants, which are able to synthesize many drugs that are currently in use (e.g. antimicrobials, antitumor, immunosuppressants, etc.). The marine environment is another well-established source of bioactive natural products, with recent applications against parasites, bacteria and other pathogens which affect humans and animals. Drug discovery techniques have rapidly advanced since the beginning of the millennium. The combination of novel techniques that include the genetic modification of pathogens, bioimaging and robotics has given rise to the standardization of High-Performance Screening platforms in the discovery of drugs. These advancements have accelerated the discovery of new chemical entities with antiparasitic effects. This review presents critical updates regarding the use of High-Throughput Screening (HTS) in the discovery of drugs for NTDs transmitted by protozoa, including malaria, and its application in the discovery of new drugs of marine origin.

Structure-Guided Design, Synthesis, and Biological Evaluation of (2-(1H-Indol-3-yl)-1H-imidazol-4-yl)(3,4,5-trimethoxyphenyl) Methanone (ABI-231) Analogues Targeting the Colchicine Binding Site in Tubulin

ABI-231 is a potent, orally bioavailable tubulin inhibitor that interacts with the colchicine binding site and is currently undergoing clinical trials for prostate cancer. Guided by the crystal structure of ABI-231 in complex with tubulin, we performed structure-activity relationship studies around the 3-indole moiety that led to the discovery of several potent ABI-231 analogues, most notably 10ab and 10bb. The crystal structures of 10ab and 10bb in complex with tubulin confirmed their improved molecular interactions to the colchicine site. In vitro, biological studies showed that new ABI-231 analogues disrupt tubulin polymerization, promote microtubule fragmentation, and inhibit cancer cell migration. In vivo, analogue 10bb not only significantly inhibits primary tumor growth and decreases tumor metastasis in melanoma xenograft models but also shows a significant ability to overcome paclitaxel resistance in a taxane-resistant PC-3/TxR model. In addition, pharmacological screening suggested that 10bb has a low risk of potential off-target function.

Real-life activity of eribulin mesylate among metastatic breast cancer patients in the multicenter national observational ESME program

Eribulin mesylate (EM) was recently approved for metastatic breast cancer (MBC) chemotherapy (CT) in late lines by the FDA, with debated results in second line. We evaluated outcomes in breast cancer patients receiving EM as second, third and fourth line in a national real-life cohort of 16,703 consecutive MBC patients initiating their first metastatic therapeutic line between 2008 and 2014. Primary and secondary objectives were overall survival (OS) and progression-free survival (PFS). An imbalance was seen for HER2+ tumors and concomitant anti-HER2 targeted therapies use, we thus performed a subanalysis in HER2- patients. PFS and OS were significantly better in EM patients in third and fourth lines, compared to "Other chemotherapies" patients (PFS: 4.14 vs. 3.02 months, p = 0.0010; 3.61 vs. 2.53 months, p = 0.0102, third and fourth-line; OS: 11.27 vs. 7.65 months, p = 0.0001; 10.91 vs. 5.95 months, p < 0.0001, third and fourth-line). No significant difference was reported in second-line (PFS: 5.06 vs. 4.14 months, p = 0.1171; OS: 13.99 vs. 11.66 months, p = 0.151). Among HER2- patients, a significant difference was seen for all lines, including 2nd-line (PFS: 4.57 vs. 3.91 months, p = 0.0379; OS: 14.98 vs. 10.51 months, p = 0.0113). In this large real-world database, HER2-negative MBC patients receiving EM in second or later CT line presented significantly better PFS and OS. This difference disappeared in second line in the overall population, probably because of the imbalance in HER2-targeted treatments use. Our results mirror those of the published randomized trials. The effect of anti-HER2 therapies addition in this setting still needs to be defined.

Marine-Derived Anticancer Agents: Clinical Benefits, Innovative Mechanisms, and New Targets

The role of the marine environment in the development of anticancer drugs has been widely reviewed, particularly in recent years. However, the innovation in terms of clinical benefits has not been duly emphasized, although there are important breakthroughs associated with the use of marine-derived anticancer agents that have altered the current paradigm in chemotherapy. In addition, the discovery and development of marine drugs has been extremely rewarding with significant scientific gains, such as the discovery of new anticancer mechanisms of action as well as novel molecular targets. Approximately 50 years since the approval of cytarabine, the marine-derived anticancer pharmaceutical pipeline includes four approved drugs and eighteen agents in clinical trials, six of which are in late development. Thus, the dynamic pharmaceutical pipeline consisting of approved and developmental marine-derived anticancer agents offers new hopes and new tools in the treatment of patients afflicted with previously intractable types of cancer.

Katanin P80 expression correlates with lymph node metastasis and worse overall survival in patients with breast cancer

OBJECTIVE

The aim of this study was to investigate the correlation of katanin P80 expression with clinicopathological features and overall survival (OS) in surgical breast cancer (BC) patients.

METHODS

Four hundred and fourteen BC patients underwent surgery were analyzed in this retrospective cohort study. Katanin P80 expression was examined by immunofluorescence assay. The median follow-up duration was 118.0 months (quantiles: 99.0-140.5 months), the last follow-up date was Jul 1st 2017.

RESULTS

Eighty-five patients (20.5%) with katanin P80 positive expression and 329 patients (79.5%) with katanin P80 negative expression were observed in this research. Katanin P80 positive expression was correlated with higher N stage (p< 0.001) and TNM stage (p< 0.001). K-M curve and log-rank test revealed that katanin P80 positive patients presented with shorter OS compared with katanin P80 negative patients (p< 0.001). Multivariate Cox's regression analysis disclosed that katanin P80 positive expression (p< 0.001) and histologic grade (p< 0.001) could independently predict unfavorable OS. Furthermore, subgroups analysis was performed, which illuminated that katanin P80 positive expression was correlated with shorter OS in all subgroups divided by molecular subtyping and TNM stage (all p< 0.05) except in TNM stage I subgroup (p= 0.573).

CONCLUSION

Katanin P80 expression positively correlated with lymph node metastasis and could abe a novel biomarker for prognosis in BC patients.

Safety of eribulin as third-line chemotherapy in HER2-negative, advanced breast cancer pre-treated with taxanes and anthracycline: OnSITE study

Eribulin is active and safe in heavily pre-treated metastatic breast cancer patients. Few safety data have been published in third line. We aimed to report the specific safety profile on third line beyond taxanes and anthracyclines in advanced breast cancer (ABC). A multicenter phase II, prospective study was conducted in anthracyclines and taxanes pre-treated HER2-negative ABC, programmed to receive eribulin as third-line chemotherapy. Adverse events (AEs) were assessed and classified according to CTCAE. In addition, efficacy, in terms of overall survival (OS) and progression-free survival (PFS), and the dynamics of circulating tumor cells (CTCs) during treatment were assessed. 59 patients fulfilled the criteria. All but one showed AEs with a cumulative number of 598 AEs. The most frequent grade 3/4 drug-related AEs were neutropenia (1.7%), febrile neutropenia (0.5%), leukopenia (0.5%), alopecia (0.5%), asthenia (0.3%), elevated gamma glutamyl transferase levels (0.2%), and respiratory tract infection (0.2%). Median PFS was 4 months (95% CI 3.1-5.9) and median OS was 13.6 months (11.8-not reached). The mean number of CTCs in peripheral blood was significantly reduced from baseline to cycle 2 (16.8 vs 5.4 CTCs; P < 0.001). Median OS was significantly longer in <5 baseline CTC patients compared to ≥5 baseline CTC patients (13.1 months [95% CI: 11.8-not reached] vs 12.5 months [95% CI: 7.6-not reached]; P = 0.045). A significant correlation (P = 0.0129) was observed between CTC levels at cycle 2 and death when CTCs were analyzed using cox regression. Eribulin chemotherapy is effective and safe as third line in advanced HER2-negative breast cancer. CTC levels correlate with overall survival.

Effect of bis(hydroxymethyl) alkanoate curcuminoid derivative MTH-3 on cell cycle arrest, apoptotic and autophagic pathway in triple-negative breast adenocarcinoma MDA-MB-231 cells: An in vitro study

Curcumin has been shown to exert potential antitumor activity in vitro and in vivo involved in multiple signaling pathways. However, the application of curcumin is still limited because of its poor hydrophilicity and low bio-availability. In the present study, we investigated the therapeutic effects of a novel and water soluble bis(hydroxymethyl) alkanoate curcuminoid derivative, MTH-3, on human breast adenocarcinoma MDA-MB-231 cells. This study investigated the effect of MTH-3 on cell viability, cell cycle and induction of autophagy and apoptosis in MDA-MB-231 cells. After 24-h treatment with MTH-3, a concentration-dependent decrease in MDA-MB-231 cell viability was observed, and the IC₅₀ value was 5.37±1.22 μM. MTH-3 significantly triggered G₂/M phase arrest and apoptosis in MDA-MB-231 cells. Within a 24-h treatment, MTH-3 decreased the CDK1 activity by decreasing CDK1 and cyclin B1 protein levels. MTH-3-induced apoptosis was further confirmed by morphological assessment and Annexin V/PI staining assay. Induction of apoptosis caused by MTH-3 was accompanied by an apparent increase of DR3, DR5 and FADD and, as well as a marked decrease of Bcl-2 and Bcl-xL protein expression. MTH-3 also decreased the protein levels of Ero1, PDI, PERK and calnexin, as well as increased the expression of IRE1α, CHOP and Bip that consequently led to ER stress and MDA-MB-231 cell apoptosis. In addition, MTH-3-treated cells were involved in the autophagic process and cleavage of LC3B was observed. MTH-3 enhanced the protein levels of LC3B, Atg5, Atg7, Atg12, p62 and Beclin-1 in MDA-MB-231 cells. Finally, DNA microarray was carried out to investigate the level changes of gene expression modulated by MTH-3 in MDA-MB-231 cells. Taken together, our results suggest that MTH-3 might be a novel therapeutic agent for the treatment of triple-negative breast cancer in the near future.

Identification of pyrrolopyrimidine derivative PP-13 as a novel microtubule-destabilizing agent with promising anticancer properties

Despite the emergence of targeted therapies and immunotherapy, chemotherapy remains the gold-standard for the treatment of most patients with solid malignancies. Spindle poisons that interfere with microtubule dynamics are commonly used in chemotherapy drug combinations. However, their troublesome side effects and the emergence of chemoresistance highlight the need for identifying alternative agents. We performed a high throughput cell-based screening and selected a pyrrolopyrimidine molecule (named PP-13). In the present study, we evaluated its anticancer properties in vitro and in vivo. We showed that PP-13 exerted cytotoxic effects on various cancer cells, including those resistant to current targeted therapies and chemotherapies. PP-13 induced a transient mitotic blockade by interfering with both mitotic spindle organization and microtubule dynamics and finally led to mitotic slippage, aneuploidy and direct apoptotic death. PP-13 was identified as a microtubule-targeting agent that binds directly to the colchicine site in β-tubulin. Interestingly, PP-13 overcame the multidrug-resistant cancer cell phenotype and significantly reduced tumour growth and metastatic invasiveness without any noticeable toxicity for the chicken embryo in vivo. Overall, PP-13 appears to be a novel synthetic microtubule inhibitor with interesting anticancer properties and could be further investigated as a potent alternative for the management of malignancies including chemoresistant ones.

Efficacy and safety of doublet versus single agent as salvage treatment for metastatic breast cancer pretreated with anthracyclines and taxanes: a systematic review and meta-analysis

AIM

To perform a systematic review and meta-analysis of randomized controlled trials to compare the efficacy and safety of doublet versus single agent as salvage treatment for pretreated metastatic breast cancer.

METHODS

A comprehensive literature search was performed to identify relevant randomized controlled trials (RCTs). All clinical studies were independently identified by two authors for inclusion. Demographic data, treatment regimens, objective response rate (ORR), and progression-free survival (PFS) and overall survival (OS) were extracted and analyzed using Comprehensive MetaAnalysis software (Version 2.0).

RESULTS

Thirteen RCTs involving 4878 pretreated metastatic breast cancer patients were ultimately identified. The pooled results demonstrated that doublet combination therapy significantly improved ORR (RR 1.13, 95% CI: 1.01-1.27, p < .001) and PFS (hazard ration [HR] 0.83, 95% CI: 0.73-0.96, p = .011), but not OS (HR 0.93, 95% CI: 0.86-1.01, p = .065). Similar results were observed in sub-group analysis according to treatment regimens. Additionally, more incidences of grade 3 or 4 myelosuppression toxicities nausea and fatigue were observed in doublet combination therapy.

CONCLUSIONS

In comparison with a single agent alone, doublet combination therapy as salvage treatment for pretreated metastatic breast cancer patients significantly improves ORR and PFS, but not OS. Further studies are recommended to identify patients who will most likely benefit from the appropriate doublet combination therapy.