INOVATYON/ ENGOT-ov5 study: Randomized phase III international study comparing trabectedin/pegylated liposomal doxorubicin (PLD) followed by platinum at progression vs carboplatin/PLD in patients with recurrent ovarian cancer progressing within 6-12 months after last platinum line.

BACKGROUND: This trial investigated the hypothesis that the treatment with trabectedin/PLD (TP) to extend the platinum-free interval (TFIp) can improve overall survival (OS) in patients with recurrent ovarian cancer (OC). METHODS: Patients with OC (up to two previous platinum-based lines), with a TFIp of 6-12 months, were randomised to receive carboplatin/PLD (CP) or TP followed by platinum therapy at relapse. The primary endpoint was OS (HR: 0.75). RESULTS: The study enrolled 617 patients. The median TFIp was 8.3 months and 30.3% of patients had received two previous platinum lines. 74% and 73.9% of patients, respectively, received a subsequent therapy (ST) in the CP and TP arm; in the latter TP arm 87.2% of ST was platinum-based, as per protocol. The median OS was 21.4 for CP and 21.9 months for TP (HR 1.13; 95% CI: 0.94-1.35; p = 0.197). Grade 3-5 adverse reactions occurred in 37.1% of patients in the CP arm and 69.7% of patients in the TP arm, and the most frequent were neutropenia (22.8% CP, 39.5% TP), gastrointestinal (7.1% CP, 17.4% TP), hepatic (0.7% CP, 19.1% TP). CONCLUSIONS: This study did not meet the primary endpoint. CP combination remains the standard for patients with recurrent OC and a 6-12 months TFIp; TP is an effective treatment in patients suffering from persistent platinum toxicities. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, number NCT01379989.

A systems biology approach to investigate the mechanism of action of trabectedin in a model of myelomonocytic leukemia.

This study was designed to investigate the mode of action of trabectedin in myelomonocytic leukemia cells by applying systems biology approaches to mine gene expression profiling data and pharmacological assessment of the cellular effects. Significant enrichment was found in regulons of target genes inferred for specific transcription factors, among which MAFB was the most upregulated after treatment and was central in the transcriptional network likely to be relevant for the specific therapeutic effects of trabectedin against myelomonocytic cells. Using the Connectivity Map, similarity among transcriptional signatures elicited by treatment with different compounds was investigated, showing a high degree of similarity between transcriptional signatures of trabectedin and those of the topoisomerase I inhibitor, irinotecan, and an anti-dopaminergic antagonist, thioridazine. The study highlights the potential importance of systems biology approaches to generate new hypotheses that are experimentally testable to define the specificity of the mechanism of action of drugs.

Mechanism of action of trabectedin in desmoplastic small round cell tumor cells.

BACKGROUND: Desmoplastic small round cell tumor (DSRCT) is a rare and highly aggressive disease, that can be described as a member of the family of small round blue cell tumors. The molecular diagnostic marker is the t(11;22)(p13;q12) translocation, which creates an aberrant transcription factor, EWS-WT1, that underlies the oncogenesis of DSRCT. Current treatments are not very effective so new active drugs are needed. Trabectedin, now used as a single agent for the treatment of soft tissue sarcoma, was reported to be active in some pre-treated DSRCT patients. Using JN-DSRCT-1, a cell line derived from DSRCT expressing the EWS-WT1 fusion protein, we investigated the ability of trabectedin to modify the function of the chimeric protein, as in other sarcomas expressing fusion proteins. After detailed characterization of the EWS-WT1 transcripts structure, we investigated the mode of action of trabectedin, looking at the expression and function of the oncogenic chimera. METHODS: We characterized JN-DSRCT-1 cells using cellular approaches (FISH, Clonogenicity assay) and molecular approaches (Sanger sequencing, ChIP, GEP). RESULTS: JN-DSRCT-1 cells were sensitive to trabectedin at nanomolar concentrations. The cell line expresses different variants of EWS-WT1, some already identified in patients. EWS-WT1 mRNA expression was affected by trabectedin and chimeric protein binding on its target gene promoters was reduced. Expression profiling indicated that trabectedin affects the expression of genes involved in cell proliferation and apoptosis. CONCLUSIONS: The JN-DSRCT-1 cell line, in vitro, is sensitive to trabectedin: after drug exposure, EWS-WT1 chimera expression decreases as well as binding on its target promoters. Probably the heterogeneity of chimera transcripts is an obstacle to precisely defining the molecular mode of action of drugs, calling for further cellular models of DSRCT, possibly growing in vivo too, to mimic the biological complexity of this disease.

Identification of high-grade serous ovarian cancer miRNA species associated with survival and drug response in patients receiving neoadjuvant chemotherapy: a retrospective longitudinal analysis using matched tumor biopsies.

BACKGROUND: Neoadjuvant chemotherapy (NACT) has been recognized as a reliable therapeutic strategy in patients with unresectable advanced epithelial ovarian cancer (EOC). The molecular events leading to platinum (Pt) response in NACT settings have hitherto not been explored. In the present work, longitudinal changes of miRNA expression profile were investigated to identify miRNA families with prognostic role in high-grade serous EOC patients who received the NACT regimen. PATIENTS AND METHODS: One hundred sixty-four matched tumor biopsies taken at initial laparoscopic evaluation and at interval-debulking surgery (IDS) after four courses of Pt-based therapy were selected from 82 stage IIIC-IV high-grade serous-EOC patients that were judged unsuitable for complete primary debulking and subjected the NACT protocol. miRNA profiling by microarray, real-time PCR and immuno-histochemical staining for Smad2 phosphorylation (P-Smad2) were used for data analysis. RESULTS: Analysis revealed that 369 miRNAs were differentially expressed in matched biopsies (referred to as DEMs). DEMs were not scattered across the genome, but clustered into families: miR-199, let-7, miR-30, miR-181 and miR-29. Multivariate analysis showed that miR-199a-3p, miR-199a-5p, miR-181a-5p and let-7g-5p associated with overall and progression-free survival (P < 0.05); miR-199a-3p, miR-199a-5p and miR-181a-5p associated with residual tumor volume and Pt-free interval (P < 0.05). Immuno-histochemical staining confirmed an enrichment of P-Smad2, a marker of transforming growth factor-ß activation, in tumors from patients with shorter PFS and OS, and with high levels of expression of miR-181a-5p (P < 0.05). Kaplan-Meier curves plotting concomitant expression of P-Smad2 and miR-181a-5p show significant differences in PFS and OS compared with those depicting the expression of each biomarker alone (P < 0.001). CONCLUSIONS: This study describes several miRNA families with a prognostic role in the NACT setting. It also confirms that concomitant analysis of P-Smad2 and miR-181a-5p in surgical samples may be capable of identifying those ovarian cancer patients with poor outcome and little chance of response to Pt-based NACT.

A prognostic regulatory pathway in stage I epithelial ovarian cancer: new hints for the poor prognosis assessment.

BACKGROUND: Clinical and pathological parameters of patients with epithelial ovarian cancer (EOC) do not thoroughly predict patients' outcome. Despite the good outcome of stage I EOC compared with that of stages III and IV, the risk assessment and treatments are almost the same. However, only 20% of stage I EOC cases relapse and die, meaning that only a proportion of patients need intensive treatment and closer follow-up. Thus, the identification of cell mechanisms that could improve outcome prediction and rationalize therapeutic options is an urgent need in the clinical practice. PATIENTS AND METHODS: We have gathered together 203 patients with stage I EOC diagnosis, from whom snap-frozen tumor biopsies were available at the time of primary surgery before any treatment. Patients, with a median follow-up of 7 years, were stratified into a training set and a validation set. RESULTS AND CONCLUSIONS: Integrated analysis of miRNA and gene expression profiles allowed to identify a prognostic cell pathway, composed of 16 miRNAs and 10 genes, wiring the cell cycle, 'Activins/Inhibins' and 'Hedgehog' signaling pathways. Once validated by an independent technique, all the elements of the circuit resulted associated with overall survival (OS) and progression-free survival (PFS), in both univariate and multivariate models. For each patient, the circuit expressions have been translated into an activation state index (integrated signature classifier, ISC), used to stratify patients into classes of risk. This prediction reaches the 89.7% of sensitivity and 96.6% of specificity for the detection of PFS events. The prognostic value was then confirmed in the external independent validation set in which the PFS events are predicted with 75% sensitivity and 94.7% specificity. Moreover, the ISC shows higher classification performance than conventional clinical classifiers. Thus, the identified circuit enhances the understanding of the molecular mechanisms lagging behind stage I EOC and the ISC improves our capabilities to assess, at the time of diagnosis, the patient risk of relapse.

Increased sensitivity to platinum drugs of cancer cells with acquired resistance to trabectedin.

BACKGROUND: In order to investigate the mechanisms of acquired resistance to trabectedin, trabectedin-resistant human myxoid liposarcoma (402-91/T) and ovarian carcinoma (A2780/T) cell lines were derived and characterised in vitro and in vivo. METHODS: Resistant cell lines were obtained by repeated exposures to trabectedin. Characterisation was performed by evaluating drug sensitivity, cell cycle perturbations, DNA damage and DNA repair protein expression. In vivo experiments were performed on A2780 and A2780/T xenografts. RESULTS: 402-91/T and A2780/T cells were six-fold resistant to trabectedin compared with parental cells. Resistant cells were found to be hypersensitive to UV light and did not express specific proteins involved in the nucleotide excision repair (NER) pathway: XPF and ERCC1 in 402-91/T and XPG in A2780/T. NER deficiency in trabectedin-resistant cells was associated with the absence of a G2/M arrest induced by trabectedin and with enhanced sensitivity (two-fold) to platinum drugs. In A2780/T, this collateral sensitivity, confirmed in vivo, was associated with an increased formation of DNA interstrand crosslinks. CONCLUSIONS: Our finding that resistance to trabectedin is associated with the loss of NER function, with a consequent increased sensitivity to platinum drugs, provides the rational for sequential use of these drugs in patients who have acquired resistance to trabectedin.

Pharmacokinetics of concomitant cisplatin and paclitaxel administered by hyperthermic intraperitoneal chemotherapy to patients with peritoneal carcinomatosis from epithelial ovarian cancer.

BACKGROUND: Hyperthermic intraperitoneal chemotherapy (HIPEC) is advised as a treatment option for epithelial ovarian cancer (EOC) with peritoneal carcinomatosis. This study was designed to define the pharmacokinetics of cisplatin (CDDP) and paclitaxel (PTX) administered together during HIPEC. METHODS: Thirteen women with EOC underwent cytoreductive surgery (CRS) and HIPEC, with CDDP and PTX. Blood, peritoneal perfusate and tissue samples were harvested to determine drug exposure by high-performance liquid chromatography and matrix-assisted laser desorption ionization imaging mass spectrometry (IMS). RESULTS: The mean maximum concentrations of CDDP and PTX in perfusate were, respectively, 24.8±10.4 µg ml(-1) and 69.8±14.3 µg ml(-1); in plasma were 1.87±0.4 µg ml(-1) and 0.055±0.009 µg ml(-1). The mean concentrations of CDDP and PTX in peritoneum at the end of HIPEC were 23.3±8.0 µg g(-1) and 30.1±18.3 µg(-1)g(-1), respectively. The penetration of PTX into the peritoneal wall, determined by IMS, was about 0.5 mm. Grade 3-4 surgical complications were recorded in four patients, five patients presented grade 3 and two patients presented grade 4 hematological complications. CONCLUSIONS: HIPEC with CDDP and PTX after CRS is feasible with acceptable morbidity and has a favorable pharmacokinetic profile: high drug concentrations are achieved in peritoneal tissue with low systemic exposure. Larger studies are needed to demonstrate its efficacy in patients with microscopic postsurgical residual tumours in the peritoneal cavity.

Profiling cancer gene mutations in longitudinal epithelial ovarian cancer biopsies by targeted next-generation sequencing: a retrospective study.

BACKGROUND: The majority of patients with stage III-IV epithelial ovarian cancer (EOC) relapse after initially responding to platinum-based chemotherapy, and develop resistance. The genomic features involved in drug resistance are unknown. To unravel some of these features, we investigated the mutational profile of genes involved in pathways related to drug sensitivity in a cohort of matched tumors obtained at first surgery (Ft-S) and second surgery (Sd-S). PATIENTS AND METHODS: Matched biopsies (33) taken at Ft-S and Sd-S were selected from the 'Pandora' tumor tissue collection. DNA libraries for 65 genes were generated using the TruSeq Custom Amplicon kit and sequenced on MiSeq (Illumina). Data were analyzed using a high-performance cluster computing platform (Cloud4CARE project) and independently validated. RESULTS: A total of 2270 somatic mutations were identified (89.85% base substitutions 8.19% indels, and 1.92% unknown). Homologous recombination (HR) genes and TP53 were mutated in the majority of Ft-S, while ATM, ATR, TOP2A and TOP2B were mutated in the entire dataset. Only 2% of mutations were conserved between matched Ft-S and Sd-S. Mutations detected at second surgery clustered patients in two groups characterized by different mutational profiles in genes associated with HR, PI3K, miRNA biogenesis and signal transduction. CONCLUSIONS: There was a low level of concordance between Ft-S and Sd-S in terms of mutations in genes involved in key processes of tumor growth and drug resistance. This result suggests the importance of future longitudinal analyses to improve the clinical management of relapsed EOC.

Trabectedin, a drug acting on both cancer cells and the tumour microenvironment.

Trabectedin is the first marine-derived anti-neoplastic drug approved for the treatment of advanced soft tissue sarcoma and, in combination with pegylated liposomal doxorubicin, for the treatment of patients with relapsed platinum-sensitive ovarian cancer. From the beginning of its development, trabectedin showed some peculiar properties that clearly distinguished it from other anti-cancer drugs. In this mini-review, we will outline the current state of knowledge regarding the mode of action of trabectedin, which appears to represent a new class of anti-neoplastic drugs acting both on cancer cells and on the tumour microenvironment.

Phase I/IIa study evaluating the safety, efficacy, pharmacokinetics, and pharmacodynamics of lucitanib in advanced solid tumors.

BACKGROUND: Lucitanib is a potent, oral inhibitor fibroblast growth factor receptor types 1 and 2 (FGFR), vascular endothelial growth factor receptor types 1, 2, and 3 (VEGFR), platelet-derived growth factor receptor types α and ß (PGFRα/ß), which are essential kinases for tumor growth, survival, migration, and angiogenesis. Several tumor types, including breast carcinoma, demonstrate amplification of fibroblast growth factor (FGF)-related genes. There are no approved drugs for molecularly defined FGF-aberrant (FGFR1- or FGF3/4/19-amplified) tumors. METHODS: This open-label phase I/IIa study involved a dose-escalation phase to determine maximum tolerated dose (MTD), recommended dose (RD), and pharmacokinetics of lucitanib in patients with advanced solid tumors, followed by a dose-expansion phase to obtain preliminary evidence of efficacy in patients who could potentially benefit from treatment (i.e. with tumors harboring FGF-aberrant pathway or considered angiogenesis-sensitive). RESULTS: Doses from 5 to 30 mg were evaluated with dose-limiting toxic effects dominated by vascular endothelial growth factor (VEGF) inhibition-related toxic effects at the 30 mg dose level (one case of grade 4 depressed level of consciousness and two cases of grade 3 thrombotic microangiopathy). The most common adverse events (all grades, all cohorts) were hypertension (91%), asthenia (42%), and proteinuria (57%). Exposure increased with dose and t½ was 31-40 h, suitable for once daily administration. Seventy-six patients were included. All but one had stage IV; 42% had >3 lines of previous chemotherapy. Sixty-four patients were assessable for response; 58 had measurable disease. Clinical activity was observed at all doses tested with durable Response Evaluation Criteria In Solid Tumors (RECIST) partial responses in a variety of tumor types. In the angiogenesis-sensitive group, objective RECIST response rate (complete response + partial response) was 26% (7 of 27) and progression-free survival (PFS) was 25 weeks. In assessable FGF-aberrant breast cancer patients, 50% (6 of 12) achieved RECIST partial response with a median PFS of 40.4 weeks for all treated patients. CONCLUSION: Lucitanib has promising efficacy and a manageable side-effect profile. The spectrum of activity observed demonstrates clinical benefit in both FGF-aberrant and angiogenesis-sensitive populations. A comprehensive phase II program is planned.

A biodistribution study of PEGylated PCL-based nanoparticles in C57BL/6 mice bearing B16/F10 melanoma.

One of the major drawbacks that limits the clinical application of nanoparticles is the lack of preliminary investigations related to their biocompatibility, biodegradability and biodistribution. In this work, biodegradable PEGylated polymer nanoparticles (NPs) have been synthesized by using macromonomers based on poly(ε-caprolaconte) oligomers. More in detail, NPs have been produced by adopting a surfactant-free semibatch emulsion polymerization process using PEG chains as a stabilizing agent. The NPs were also labeled with rhodamine B covalently bound to the NPs to quantitatively study their biodistribution in vivo. NPs were investigated in both in vitro and in vivo preclinical systems to study their biodistribution in mice bearing B16/F10 melanoma, as well as their biocompatibility and biodegradability. The NP concentration was evaluated in different tissues at several times after intravenous injection. The disappearance of the NPs from the plasma was biphasic, with distribution and elimination half-lives of 30 min and 15 h, respectively. NPs were retained in tumors and in filter organs for a long time, were still detectable after 7 d and maintained a steady concentration in the tumor for 120 h. 48 h after injection, 70 ± 15% of the inoculated NPs were excreted in the feces. The favorable tumor uptake, fast excretion and absence of cytotoxicity foster the further development of produced NPs as drug delivery carriers.

Characterization of a new trabectedin-resistant myxoid liposarcoma cell line that shows collateral sensitivity to methylating agents.

Myxoid Liposarcomas (MLS), characterized by the expression of FUS-CHOP fusion gene are clinically very sensitive to the DNA binding antitumor agent, trabectedin. However, resistance eventually occurs, preventing disease eradication. To investigate the mechanisms of resistance, a trabectedin resistant cell line, 402-91/ET, was developed. The resistance to trabectedin was not related to the expression of MDR related proteins, uptake/efflux of trabectedin or GSH levels that were similar in parental and resistant cells. The 402-91/ET cells were hypersensitive to UV light because of a nucleotide excision repair defect: XPG complementation decreased sensitivity to UV rays, but only partially to trabectedin. 402-91/ET cells showed collateral sensitivity to temozolomide due to the lack of O(6) -methylguanine-DNA-methyltransferase (MGMT) activity, related to the hypermethylation of MGMT promoter. In 402-91 cells chromatin immunoprecipitation (ChIP) assays showed that FUS-CHOP was bound to the PTX3 and FN1 gene promoters, as previously described, and trabectedin caused FUS-CHOP detachment from DNA. Here we report that, in contrast, in 402-91/ET cells, FUS-CHOP was not bound to these promoters. Differences in the modulation of transcription of genes involved in different pathways including signal transduction, apoptosis and stress response between the two cell lines were found. Trabectedin activates the transcription of genes involved in the adipogenic-program such as c/EBPα and ß, in 402-91 but not in 402-91/ET cell lines. The collateral sensitivity of 402-91/ET to temozolomide provides the rationale to investigate the potential use of methylating agents in MLS patients resistant to trabectedin.

Alternative academic approaches for testing homologous recombination deficiency in ovarian cancer in the MITO16A/MaNGO-OV2 trial.

BACKGROUND: The detection of homologous recombination deficiency (HRD) can identify patients who are more responsive to platinum and poly ADP ribose polymerase inhibitors (PARPi). MyChoice CDx (Myriad) is the most used HRD test in ovarian cancer (OC). However, some limitations of commercial tests exist, because of the high rate of inconclusive results, costs, and the impossibility of evaluating functional resistance mechanisms. PATIENTS AND METHODS: Two academic genomic tests and a functional assay, the RAD51 foci, were evaluated to detect HRD. One hundred patients with high-grade OC enrolled in the MITO16A/MaNGO-OV2 trial and treated with first-line therapy with carboplatin, paclitaxel, and bevacizumab were analyzed. RESULTS: The failure rate of the two genomic assays was 2%. The sensitivity in detecting HRD when compared with Myriad was 98.1% and 90.6%, respectively. The agreement rate with Myriad was 0.92 and 0.87, with a Cohen's κ coefficient corresponding to 0.84 and 0.74, respectively. For the RAD51 foci assay, the failure rate was 30%. When the test was successful, discordant results for deficient and proficient tumors were observed, and additional HRD patients were identified compared to Myriad; sensitivity was 82.9%, agreement rate was 0.65, and Cohen's κ coefficient was 0.18. The HRD detected by genomic assays and residual tumor at primary surgery and stage was correlated with progression-free survival at multivariate analysis. CONCLUSIONS: Results suggest the feasibility of academic tests for assessing HRD status that show robust concordance with Myriad and correlation with clinical outcome. The contribution of the functional information related to the RAD51 foci test to the genomic data needs further investigation.

COVID-19 epidemic strongly affected cancer research in Italy: a survey of the Italian Cancer Society (SIC).

BACKGROUND: Italy was among the first countries hit by the pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The application of strict lockdown measures disproportionately affected both cancer patient care as well as basic and translational cancer research. MATERIALS AND METHODS: The Italian Cancer Society (SIC) conducted a survey on the effect of lockdown on laboratories involved in cancer research in Italy. The survey was completed by 570 researchers at different stages of their career, working in cancer centers, research institutes and universities from 19 Italian regions. RESULTS: During the lockdown period, the impact of the COVID-19 pandemic emergency on face-to-face research activities was high, with a complete (47.7%) or partial (36.1%) shutdown of the laboratories. In the post-lockdown period, research activities were resumed in most of the respondents' institutions (80.4%), though with some restrictions (77.2%). COVID-19 testing was offered to research personnel only in ~50% of research institutions. Overall, the response to the pandemic was fragmented as in many cases institutions adopted different strategies often aimed at limiting possible infections without a clearly defined contingency plan. Nevertheless, research was able to provide the first answers and possible ways out of the pandemic, also with the contribution of many cancer researchers that sacrificed their research programs to help overcome the pandemic by offering their knowledge and technologies. CONCLUSIONS: Given the current persistence of an emergency situation in many European countries, a more adequate organization of research centers will be urgent and necessary to ensure the continuity of laboratory activities in a safe environment.

Trabectedin in myxoid liposarcomas (MLS): a long-term analysis of a single-institution series.

BACKGROUND: Trabectedin has been approved in Europe as second-line therapy for advanced soft tissue sarcomas. A previous analysis showed that myxoid liposarcomas (MLS) are particularly sensitive to the drug. We report on the long-term efficacy of trabectedin in a subgroup of that series. METHODS: Since September 2002, 32 advanced pretreated MLS patients received trabectedin at our center. Data were reviewed focusing on their long-term outcome. RESULTS: Trabectedin was given as a 24-h continuous infusion every 21 days. A total of 376 and a median of 12 courses per patient (range 2-26; interquartiles range (IQR) 8-15) were delivered. Response rate per RECIST was 50% [95% confidence interval (CI) 32% to 68%], median progression-free survival (PFS) was 17 months (95% CI 13.5-30.1) and median overall survival is still not reached. In 10 patients, therapy was stopped in the absence of any evident disease, mostly after complete surgery of residual lesions. In these 10 patients, at a median follow-up of 25 months, PFS was 28.1 months (95% CI 25.6-36.4) from treatment start. DISCUSSION: These data indicate that the high response rate of MLS to trabectedin translates into prolonged PFS. Surgery of residual metastatic disease is already used quite extensively in metastatic MLS. Trabectedin may give further significance to this kind of surgery.

Role of homologous recombination in trabectedin-induced DNA damage.

Trabectedin (ET-743, Yondelis) is a natural marine compound with antitumour activity currently undergoing phase II/III clinical trials. The mechanism of the drug's action is still to be defined, even though it has been clearly demonstrated the key role of Nucleotide Excision Repair (NER). To get further insights into the drug's mode of action, we studied the involvement of the DNA-double strand break repair (DNA-DSB) pathways: homologous and non-homologous recombination, both in budding yeasts and in mammalian cells and the possible cross-talk between NER and these repair pathways. Budding yeasts and mammalian cells deficient in the non-homologous end-joining pathway were moderately sensitive to trabectedin, while systems deficient in the homologous recombination pathway were extremely sensitive to the drug, with a 100-fold decrease in the IC50, suggesting that trabectedin-induced lesions are repaired by this pathway. The induction of Rad51 foci and the appearance of gamma-H2AX were chosen as putative markers for DNA-DSBs and were studied at different time points after trabectedin treatment in NER proficient and deficient systems. Both were clearly detected only in the presence of an active NER, suggesting that the DSBs are not directly caused by the drug, but are formed during the processing/repair of the drug- induced lesions.

Ascites interferes with the activity of lurbinectedin and trabectedin: Potential role of their binding to alpha 1-acid glycoprotein.

Trabectedin and its analogue lurbinectedin are effective drugs used in the treatment of ovarian cancer. Since the presence of ascites is a frequent event in advanced ovarian cancer we asked the question whether ascites could modify the activity of these compounds against ovarian cancer cells. The cytotoxicity induced by trabectedin or lurbinectedin against A2780, OVCAR-5 cell lines or primary culture of human ovarian cancer cells was compared by performing treatment in regular medium or in ascites taken from either nude mice or ovarian cancer patients. Ascites completely abolished the activity of lurbinectedin at up to 10nM (in regular medium corresponds to the IC90), strongly reduced that of trabectedin, inhibited the cellular uptake of lurbinectedin and, to a lesser extent, that of trabectedin. Since α1-acid glycoprotein (AGP) is present in ascites at relatively high concentrations, we tested if the binding of the drugs to this protein could be responsible for the reduction of their activity. Adding AGP to the medium at concentration range of those found in ascites, we reproduced the anticytotoxic effect of ascites. Erythromycin partially restored the activity of the drugs, presumably by displacing them from AGP. Equilibrium dialysis experiments showed that both drugs bind AGP, but the affinity of binding of lurbinectedin was much greater than that of trabectedin. KD values are 8±1.7 and 87±14nM for lurbinectedin and trabectedin, respectively. The studies intimate the possibility that AGP present in ascites might reduce the activity of lurbinectedin and to a lesser extent of trabectedin against ovarian cancer cells present in ascites. AGP plasma levels could influence the distribution of these drugs and thus they should be monitored in patients receiving these compounds.

Patient-derived solitary fibrous tumour xenografts predict high sensitivity to doxorubicin/dacarbazine combination confirmed in the clinic and highlight the potential effectiveness of trabectedin or eribulin against this tumour.

BACKGROUND: Preclinical models that mimic pathological and molecular features of solitary fibrous tumour (SFT) represent an important tool to select effective regimes and novel compounds to be tested in the clinic. This study was aimed at developing two preclinical models of SFT, assessing their predictive value in the clinic and selecting potential novel effective treatments. MATERIAL AND METHODS: Two dedifferentiated-SFT (D-SFT) models obtained from patients' biopsies were grown in immunodeficient mice. The antitumour activity on these models of doxorubicin, dacarbazine (DTIC), ifosfamide (monotherapy or combination), trabectedin and eribulin was tested. Twelve SFT patients were treated with doxorubicin and DTIC. Response by RECIST, progression-free survival and overall survival were retrospectively evaluated, distinguishing malignant-SFT (M-SFT) and D-SFT. RESULTS: Two D-SFT patient-derived xenografts (PDXs) that represent the first available preclinical in vivo models of SFT were developed and characterised. Doxorubicin/DTIC, DTIC/ifosfamide, doxorubicin/ifosfamide combinations consistently induced better antitumour activity than the single-agents. Particularly, doxorubicin/DTIC combination caused a max tumour volume inhibition >80% in both models. Doxorubicin/DTIC combo showed activity also in the case-series. Best RECIST responses were: 6 responses (M-SFT = 2 of 7, D-SFT = 4 of 5), 1 stable disease, 5 progressions, with a 6-month median progression-free survival (M-SFT = 6, D-SFT = 10 months). The PDXs were very sensitive to trabectedin and eribulin. CONCLUSION: Doxorubicin plus DTIC combination was effective in our two D-SFT mice models and appeared to be active also in the clinic, especially in high-grade D-SFT patients. Among additional drugs tested in the PDXs, trabectedin and eribulin were highly effective, providing a rational to test these drugs in D-SFT patients.