Hepatic safety analysis of trabectedin: results of a pharmacokinetic study with trabectedin in patients with hepatic impairment and experience from a phase 3 clinical trial.

Purpose Trabectedin is metabolized by the liver and has been associated with transient, noncumulative transaminase elevation. Two recent studies further characterize hepatic tolerability with trabectedin therapy: a phase 1 pharmacokinetic study (Study #1004; NCT01273493) in patients with advanced malignancies and hepatic impairment (HI), and a phase 3 study (Study #3007; NCT01343277) of trabectedin vs. dacarbazine in patients with advanced sarcomas and normal hepatic function. Methods In Study #1004, patients received a single 3-h intravenous (IV) infusion of trabectedin: control group, trabectedin 1.3 mg/m2; HI group (baseline total bilirubin >1.5 and ≤3× upper limit of normal [ULN]; AST and ALT ≤2.5× ULN), trabectedin 0.58 or 0.9 mg/m2. In Study #3007, the trabectedin group received 1.5 mg/m2 by 24-h IV infusion every 3 weeks until disease progression or unacceptable toxicity. Results In Study #1004, dose-normalized trabectedin exposure was higher in HI patients (n = 6) versus controls (n = 9) (geometric mean ratios [90% CI] AUClast: 1.97 [1.20; 3.22]). In Study #3007, following trabectedin administration, 90% of patients had elevated ALT (32% grade 3-4) and 84% had elevated AST (17% grade 3-4). Transaminase elevations were transient and noncumulative. Progression-free survival was similar in patients with grade 3-4 hepatotoxicity (n = 109) versus grade 0-2 hepatotoxicity (n = 231) (median [95% CI]: 4.63 [4.01, 5.85] months versus 3.55 [2.73, 4.63] months; P = 0.545, HR = 0.91 [0.68-1.23]). Conclusion Trabectedin treatment of patients with HI results in higher plasma exposures. Hepatotoxicity in patients with normal liver function can be effectively addressed through dose reductions and delays.

Efficacy and safety of trabectedin or dacarbazine in patients with advanced uterine leiomyosarcoma after failure of anthracycline-based chemotherapy: Subgroup analysis of a phase 3, randomized clinical trial.

OBJECTIVE: Trabectedin demonstrated significantly improved disease control in leiomyosarcoma and liposarcoma patients in a global phase 3 trial (NCT01343277). A post hoc analysis was conducted to assess the efficacy and safety of trabectedin or dacarbazine in women with uterine leiomyosarcoma (uLMS), the largest subgroup of enrolled patients (40%). METHODS: Of 577 patients randomized 2:1 to receive trabectedin 1.5mg/m2 by 24-hour IV infusion or dacarbazine 1g/m2 by 20-120-minute IV infusion once every three weeks, 232 had uLMS (trabectedin: 144; dacarbazine: 88). The primary endpoint was overall survival (OS); secondary endpoints were progression-free survival (PFS), objective response rate (ORR), clinical benefit rate (CBR: complete responses+partial responses+stable disease [SD] for at least 18weeks), duration of response (DOR), and safety. RESULTS: PFS for trabectedin was 4.0months compared with 1.5months for dacarbazine (hazard ratio [HR]=0.57; 95% CI 0.41-0.81; P=0.0012). OS was similar (trabectedin 13.4months vs. dacarbazine 12.9months, HR=0.89; 95% CI 0.65-1.24; P=0.51) between groups. ORR was 11% with trabectedin vs. 9% with dacarbazine (P=0.82). CBR for trabectedin was 31% vs. 18% with dacarbazine (P=0.05); median DOR was 6.5months for trabectedin vs. 4.1months for dacarbazine (P=0.32). Grade 3/4 treatment-emergent adverse events observed in ≥10% of patients in the trabectedin group included transient aminotransferase (aspartate/alanine) elevations, anemia, leukopenia, and thrombocytopenia. CONCLUSIONS: In this post hoc subset analysis of patients with uLMS who had received prior anthracycline therapy, trabectedin treatment resulted in significantly longer PFS versus dacarbazine, with an acceptable safety profile. There was no difference in OS.

Efficacy and Safety of Trabectedin or Dacarbazine for Metastatic Liposarcoma or Leiomyosarcoma After Failure of Conventional Chemotherapy: Results of a Phase III Randomized Multicenter Clinical Trial.

PURPOSE: This multicenter study, to our knowledge, is the first phase III trial to compare trabectedin versus dacarbazine in patients with advanced liposarcoma or leiomyosarcoma after prior therapy with an anthracycline and at least one additional systemic regimen. PATIENTS AND METHODS: Patients were randomly assigned in a 2:1 ratio to receive trabectedin or dacarbazine intravenously every 3 weeks. The primary end point was overall survival (OS), secondary end points were disease control-progression-free survival (PFS), time to progression, objective response rate, and duration of response-as well as safety and patient-reported symptom scoring. RESULTS: A total of 518 patients were enrolled and randomly assigned to either trabectedin (n = 345) or dacarbazine (n = 173). In the final analysis of PFS, trabectedin administration resulted in a 45% reduction in the risk of disease progression or death compared with dacarbazine (median PFS for trabectedin v dacarbazine, 4.2 v 1.5 months; hazard ratio, 0.55; P < .001); benefits were observed across all preplanned subgroup analyses. The interim analysis of OS (64% censored) demonstrated a 13% reduction in risk of death in the trabectedin arm compared with dacarbazine (median OS for trabectedin v dacarbazine, 12.4 v 12.9 months; hazard ratio, 0.87; P = .37). The safety profiles were consistent with the well-characterized toxicities of both agents, and the most common grade 3 to 4 adverse effects were myelosuppression and transient elevation of transaminases in the trabectedin arm. CONCLUSION: Trabectedin demonstrates superior disease control versus conventional dacarbazine in patients who have advanced liposarcoma and leiomyosarcoma after they experience failure of prior chemotherapy. Because disease control in advanced sarcomas is a clinically relevant end point, this study supports the activity of trabectedin for patients with these malignancies.

Impact of cytochrome P450 3A4 inducer and inhibitor on the pharmacokinetics of trabectedin in patients with advanced malignancies: open-label, multicenter studies.

PURPOSE: To evaluate the pharmacokinetics, safety and survival of trabectedin, metabolized primarily by cytochrome P450 (CYP)3A4 enzyme, when coadministered with rifampin (CYP3A4 inducer) or ketoconazole (CYP3A4 inhibitor) in adult patients with advanced solid tumors. METHODS: Two phase 1/2a, 2-way crossover studies were conducted. For rifampin study, 12 patients were randomized (1:1) to sequence of a cycle of trabectedin (1.3 mg/m(2), 3 h, i.v.) coadministered with rifampin (600 mg/day, 6-days), and a cycle of trabectedin monotherapy (1.3 mg/m(2), 3 h, i.v.). In ketoconazole study, eight patients were randomized (1:1) to sequence of a cycle of trabectedin (0.58 mg/m(2), 3 h, i.v.) coadministered with ketoconazole (200 mg, twice-daily, 15-doses), and a cycle of trabectedin monotherapy (1.3 mg/m(2), 3 h, i.v.). RESULTS: The systemic exposure (geometric means) of trabectedin was decreased [22% (C max) and 31% (AUClast)] with rifampin coadministration and increased [22% (C max) and 66% (AUClast)] with ketoconazole coadministration. This correlated with an increased clearance with rifampin (39.6-59.8 L/h) and a decreased clearance with ketoconazole (20.3-12.0 L/h). Consistent with earlier studies, the most common (≥40%) treatment-emergent adverse events in both studies were nausea, vomiting, diarrhea, hepatic function abnormal, anemia, neutropenia, thrombocytopenia and leukopenia. CONCLUSIONS: Coadministration of rifampin or ketoconazole altered the pharmacokinetics of trabectedin, but no new safety signals were observed. Coadministration of trabectedin with potent CYP3A4 inhibitors or inducers should be avoided if possible. If coadministration of trabectedin with a strong CYP3A4 inhibitor is required, close monitoring for toxicities is recommended, so that appropriate dose reductions can be instituted as warranted.

Nibrin is a marker of clinical outcome in patients with advanced serous ovarian cancer treated in the phase III OVA-301 trial.

OBJECTIVE: This study investigated the relationship between 13 proteins involved in DNA damage and the outcomes of patients with recurrent ovarian cancer (ROC). PATIENTS AND METHODS: Immunohistochemistry staining was performed in 114 diagnostic samples from patients with serous ROC who participated in the OVA-301 study, which compared pegylated liposomal doxorubicin (PLD) with a combination of trabectedin plus PLD. Percentage of positive cells for every marker was calculated and correlated with overall response rate (ORR), progression-free survival (PFS) and overall survival (OS). RESULTS: A statistically significant correlation between high levels of nibrin and lower ORR (P=0.03), shorter PFS (P=0.007) and shorter OS (P=0.01) was observed. After stratification, in patients with platinum-sensitive disease treated with the combination of trabectedin plus PLD, high levels of nibrin correlated with lower ORR (P=0.01) and shorter PFS (P=0.02). A better clinical outcome (ORR, PFS and OS) was also associated to low levels of CHK2 in trabectedin plus PLD treated patients. No correlations were found in PLD-treated patients. According to the results of a multivariate analysis, there was a statistically significant correlation between high nibrin (P=0.001) and low BRCA2 levels (P=0.03) and a worse PFS, and between high nibrin levels and a worse OS (P=0.006). CONCLUSION: Our results indicate that high nibrin expression seems to be associated with a worse clinical outcome in serous ROC, particularly in patients treated with the combination trabectedin plus PLD. Prospective studies to determine clinical usefulness of nibrin as a possible biomarker in other series of patients with ROC are warranted.

Trabectedin plus pegylated liposomal doxorubicin (PLD) versus PLD in recurrent ovarian cancer: overall survival analysis.

AIM: Trabectedin in combination with pegylated liposomal doxorubicin (PLD) improves progression-free survival (PFS) compared to PLD alone in recurrent ovarian cancer (J Clin Oncol 2010;28:3107-14). METHODS: Women, stratified by performance status (0-1 versus 2) and platinum sensitivity (platinum-free interval [PFI]<6 versus ≥ 6 months), were randomly assigned to receive PLD 30 mg/m(2) IV followed by a 3-h infusion of trabectedin 1.1mg/m(2) every 3 weeks or PLD 50mg/m(2) every 4 weeks. The study was powered to show a 33% increase in overall survival (OS) after 520 deaths had occurred. RESULTS: After a median follow-up of 47.4 months, there were 522 deaths among 672 subjects. The median OS for trabectedin+PLD and PLD arms was 22.2 and 18.9 months, respectively (hazard ratio [HR]=0.86; 95% confidence interval [CI]: 0.72-1.02; p=0.0835). An unexpected but significant imbalance in the PFI favouring the PLD arm (mean PFI: PLD=13.3 months, trabectedin+PLD=10.6 months) was identified. On the basis of this finding, an unplanned hypothesis generating analysis adjusting for the PFI imbalance and other prognostic factors suggested an improvement in OS associated with the trabectedin+PLD arm (HR=0.82; 95%CI: 0.69-0.98; p=0.0285). In another unplanned exploratory analysis, the subset of patients with a PFI of 6-12 months had the largest difference in OS (HR=0.64; 95%CI: 0.47-0.86; p=0.0027). CONCLUSIONS: The final OS analysis did not meet the protocol-defined criterion for statistical significance. Despite stratification on platinum sensitivity, there was an imbalance in mean platinum free interval that had an effect on OS.

Transforming growth factor-beta, estrogen, and progesterone converge on the regulation of p27Kip1 in the normal and malignant endometrium.

Hormones and growth factors regulate endometrial cell growth. Disrupted transforming growth factor-beta (TGF-beta) signaling in primary endometrial carcinoma (ECA) cells leads to loss of TGF-beta-mediated growth inhibition, which we show herein results in lack of up-regulation of the cyclin-dependent kinase inhibitor p27(Kip1) (p27) to arrest cells in G(1) phase of the cell cycle. Conversely, in normal primary endometrial epithelial cells (EECs), TGF-beta induces a dose-dependent increase in p27 protein, with a total 3.6-fold maximal increase at 100 pmol/L TGF-beta, which was 2-fold higher in the nuclear fraction; mRNA levels were unaffected. In addition, ECA tissue lysates show a high rate of ubiquitin-mediated degradation of p27 compared with normal secretory-phase endometrial tissue (SE) such that 4% and 89% of recombinant p27 added to the lysates remains after 3 and 20 h, respectively. These results are reflected in vivo as ECA tissue lacks p27 compared with high expression of p27 in SE (P < or = 0.001). Furthermore, we show that estrogen treatment of EECs causes mitogen-activated protein kinase-driven proteasomal degradation of p27 whereas progesterone induces a marked increase in p27 in both normal EECs and ECA cells. Therefore, these data suggest that TGF-beta induces accumulation of p27 for normal growth regulation of EECs. However, in ECA, in addition to enhanced proteasomal degradation of p27, TGF-beta cannot induce p27 levels due to dysregulated TGF-beta signaling, thereby causing 17beta-estradiol-driven p27 degradation to proceed unchecked for cell cycle progression. Thus, p27 may be a central target for growth regulation of normal endometrium and in the pathogenesis of ECA.

The activation function-1 domain of estrogen receptor alpha in uterine stromal cells is required for mouse but not human uterine epithelial response to estrogen.

The activation function-1 (AF-1) domain of the estrogen receptor alpha (ERalpha) in stromal cells has been shown to be required for epithelial responses to estrogen in the mouse uterus. To investigate the role of the stroma in estrogenic responses of human uterine epithelium (hUtE), human/mouse chimeric uteri composed of human epithelium and mouse stroma were prepared as tissue recombinants (TR) that were grown in vivo under the renal capsule of female nude mouse hosts. In association with mouse uterine stroma (mUtS), hUtE formed normal glands surrounded by mouse endometrial stroma and the human epithelium influenced the differentiation of stroma into myometrium, such that a histologically normal appearing uterine tissue was formed. The hUtE showed a similar proliferative response and increase in progesterone receptors (PR) in response to 17beta-estradiol (E2) in association with either human or mUtS, as TRs. However, under identical endocrine and micro-environmental conditions, hUtE required 5-7 days exposure to E2 rather than 1 day, as shown for mouse uterine epithelium, to obtain a maximal proliferative response. Moreover, this extended length of E2 exposure inhibited mouse epithelial proliferation in the presence of mouse stroma. In addition, unlike the mouse epithelium, which does not proliferate or show regulation of PR expression in response to E2 in association with uterine stroma derived from mice that are null for the AF-1 domain of ERalpha, hUtE proliferates and PR are up-regulated in response to E2 in association genetically identical ERalpha knock-out mouse stromal cells. These results clearly demonstrate fundamental differences between mouse and human uterine epithelia with respect to the mechanisms that regulate estrogen-induced proliferation and expression of PR. Moreover, we show that genetically engineered mouse models could potentially aid in dissecting molecular pathways of stromal epithelial interactions in the human uterus.

Transforming growth factor beta signaling is disabled early in human endometrial carcinogenesis concomitant with loss of growth inhibition.

Transforming growth factor beta (TGF-beta), a potent ubiquitous endogenous inhibitor of epithelial cell growth, is secreted as a latent molecule (LTGF-beta)requiring activation for function. TGF-beta signals through the type I(TbetaRI) and type II (TbetaRII) receptors, which cooperate to phosphorylate/activate Smad2/3, the transcriptional regulators of genes that induce cell cycle arrest. That carcinomas grow in vivo suggests that they are refractory to TGF-beta. However, this has been difficult to prove because of an inability to analyze the functional status of TGF-beta in vivo as well as lack of close physiological paradigms for carcinoma cells in vitro. The current studies demonstrate that whereas primary cultures of endometrial epithelial cells derived from normal proliferative endometrium (PE; n = 10) were dose-dependently and maximally growth inhibited by 55% +/- 5.3% with 10 pM TGF-beta1, endometrial epithelial cells derived from endometrial carcinomas (ECAs; n = 10) were unresponsive (P < or = 0.0066). To determine the mechanism of TGF-beta resistance in ECAs, we analyzed the TGF-beta signaling pathway in vivo by immunohistochemistry using specific antibodies to TbetaRI and TbetaRII, Smads, and to the phosphorylated form of Smad2 (Smad2P), an indicator of cells responding to bioactive TGF-beta. Smad2P was expressed in all of the normal endometria (n = 25), and was localized to the cytoplasm and nucleus in PE, and only nuclear in the secretory endometrium. In marked contrast, Smad2P immunostaining was weak or undetectable in ECA (n = 22; P < or = 0.001) and reduced in glandular hyperplasia (n = 25) compared with normal endometrium. However, total Smad2 and Smad7 (which inhibits Smad2 activation) levels were identical in ECA and normal tissue. Consistent with loss of downstream signaling, both TbetaRI (n = 19) and TbetaRII (n = 22) protein expression were significantly reduced in ECA compared with PE (n = 11; P < or = 0.05). By in situ hybridization, the mRNA levels of TbetaRI and TbetaRII were decreased in the carcinoma cells compared with normal PE glands, suggesting that receptor down-regulation occurs at the transcriptional level. Furthermore, a somatic frameshift mutation in the polyadenine tract at the 5' end of the TbetaR-II gene was detected in two of six cases examined. Finally, the ability of explants of ECA to activate endogenous LTGF-beta was deficient compared with normal tissue (23.5% versus 7.4%). Therefore, our results suggest that loss of Smad2 signaling in ECA may be because of down-regulation of TbetaRI and TbetaRII, and/or decreased activation of LTGF-beta. Because disruption of TGF-beta signaling occurred independent of grade or degree of invasion and was evident in premalignant hyperplasia, we conclude that inactivation of TGF-beta signaling leading to escape from normal growth control occurs at an early stage in endometrial carcinogenesis, thereby defining novel molecular targets for cancer prevention.

Differential expression of transforming growth factor-beta type I and II receptors by pulmonary cells in bleomycin-induced lung injury: correlation with repair and fibrosis.

In a rat model of lung injury induced by the antineoplastic antibiotic, bleomycin, there is loss of type I alveolar epithelial cells (AECs) followed by infiltration of activated inflammatory cells, type II AEC proliferation, and fibrosis. At 4 and 7 days after bleomycin administration alveolar macrophages have increased production and release of active transforming growth factor (TGF)-beta1, an inhibitor of epithelial cell proliferation. Paradoxically at these same time intervals there is a concomitant induction of type II AEC proliferation. For TGF-beta-mediated signal transduction to occur, the expression of both TCF-beta receptor types I (TbetaR-I) and II (TbetaR-II) must be present. Using immunohistochemistry and in situ hybridization, 4 and 7 days after bleomycin administration the expression of TbetaR-I on AECs was reduced whereas that of TbetaR-II was unaltered. However, 14 and 28 days after bleomycin injury, when there is decreased proliferation and induction of differentiation of type II AECs, there was a return of TbetaR-I expression on AECs. In contrast, TbetaR-I and TbetaR-II were observed on interstitial fibroblasts at all time intervals after bleomycin administration. Because both TbetaR-I and TbetaR-II are required for signal transduction, the reduction of TbetaR-I levels on the alveolar epithelium may alter the sensitivity of AECs to the antiproliferative effects of TGF-beta1 present in increased quantities following bleomycin injury. The loss of an antiproliferative response to TGF-beta1 may be important for the regeneration of the alveolar epithelium by proliferation while the expression of both receptors onfibroblasts would result in TGF-1 signaling for the synthesis of connective tissue proteins. Ourfindings suggest that during bleomycin-induced pulmonary fibrosis, the effects of TGF-beta1 on cells may be regulated by the expression of TbetaRs.