Pharmacotherapeutic group: Antineoplastic agent, ATC code: L01CX01.
Mechanism of action
Trabectedin binds to the minor groove of deoxyribonucleic acid (DNA), bending the helix to the major groove. This binding to DNA triggers a cascade of events affecting several transcription factors, DNA binding proteins, and DNA repair pathways, resulting in perturbation of the cell cycle.
Pharmacodynamic effects
Trabectedin has been shown to exert antiproliferative in vitro and in vivo activity against a range of human tumour cell lines and experimental tumours, including malignancies such as sarcoma, breast, non-small cell lung, ovarian and melanoma.
Electrocardiogram (ECG) investigations
In a placebo-controlled QT/QTc study, trabectedin did not prolong the QTc interval in patients with advanced solid malignancies.
Clinical efficacy and safety
The efficacy and safety of trabectedin in soft tissue sarcoma is based in a randomised trial in patients with locally advanced or metastatic lipo- or leiomyosarcoma, whose disease had progressed or relapsed after treatment with at least anthracyclines and ifosfamide. In this trial trabectedin was administered either at 1.5 mg/m2 as a 24-hour intravenous infusion every 3 weeks or at 0.58 mg/m2 weekly as a 3-hour intravenous infusion for 3-weeks of a 4-week cycle. The protocol specified final time to progression (TTP) analysis showed a 26.6% reduction in the relative risk of progression for patients treated in the 24-h q3wk group [Hazard Ratio (HR)=0.734, Confidence Interval (CI): 0.554-0.974]. Median TTP values were 3.7 months (CI: 2.1-5.4 m) in the 24-h q3wk group and 2.3 months (CI: 2.0-3.5 m) in the 3-h qwk group (p=0.0302). No significant differences were detected in overall survival (OS). Median OS with the 24-h q3wk regimen was 13.9 months (CI: 12.5-18.6) and 60.2% of patients were alive at 1 year (CI: 52.0-68.5%).
Additional efficacy data are available from 3 single-arm Phase II trials with similar populations treated with the same regimen. These trials evaluated a total of 100 patients with lipo- and leiomyosarcoma and 83 patients with other types of sarcoma.
Results from an expanded access program for patients with STS (study ET743-SAR- 3002) show that among the 903 subjects assessed for OS, the median survival time was 11.9 months (95% CI: 11.2, 13.8). The median survival by histology tumour type was 16.2 months [95% CI: 14.1, 19.5] for subjects with leiomyosarcomas and liposarcomas and 8.4 months [95% CI: 7.1, 10.7] for subjects with other types of sarcomas. The median survival for subjects with liposarcoma was 18.1 months [95% CI: 15.0, 26.4] and for subjects with leiomyosarcoma 16.2 months [95% CI: 11.7, 24.3].
Additional efficacy data are available from a randomized active-controlled phase III study of trabectedin vs. dacarbazine (Study ET743-SAR-3007), in patients treated for unresectable or metastatic lipo- or leiomyosarcoma who have been previously treated with at least an anthracycline and ifosfamide containing regimen, or an anthracycline containing regimen and one additional cytotoxic chemotherapy regimen. Patients in the trabectedin arm were required to receive dexamethasone 20 mg intravenous injection prior to each trabectedin infusion. Overall, 384 patients were randomized to the trabectedin group [1.5 mg/m2 once every 3 weeks (q3wk 24-h)] and 193 patients to the dacarbazine group (1 g/m2 once every 3 weeks). The median patient age was 56 years (range 17 to 81), 30% were male, 77% Caucasian, 12% African American and 4% Asian. Patients in the trabectedin and dacarbazine arms received a median of 4 and 2 cycles respectively. The primary efficacy endpoint of the study was OS, which included 381 death events (66% of all randomized patients): 258 (67.2%) deaths in the trabectedin group and 123 (63.7%) deaths in the dacarbazine group (HR 0.927 [95% CI: 0.748, 1.150; p=0.4920]). The final analysis showed no significant difference with a median survival follow-up of 21.2 months resulted in a median of 13.7 months (95% CI: 12.2, 16.0) for the trabectedin arm and 13.1 months [95% CI: 9.1, 16.2] for the dacarbazine arm. The main secondary endpoints are summarized in the table below:
Efficacy results from Study ET743-SAR-3007
| Endpoints / Study population | Trabectedin | Dacarbazine | Hazard Ratio / Odds Ratio | p value |
| Primary endpoint | n=384 | n=193 | | |
| Overall survival, n (%) | 258 (67.2%) | 123 (63.7%) | 0.927 (0.748-1.150) | 0.4920 |
| Secondary endpoints | n=345 | n=173 | | |
| PFS (months; 95% CI) | 4.2 | 1.5 | 0.55 (0.44, 0.70) | <0.0001 |
| ORR, n (%); Odds ratio (95% CI) | 34 (9.9%) | 12 (6.9%) | 1.47 (0.72, 3.2) | 0.33 |
| DOR (months; 95% CI) | 6.5 | 4.2 | 0.47 (0.17, 1.32) | 0.14 |
| CBR, n (%); Odds ratio (95% CI) | 34.2% | 18.5% | 2.3 (1.45, 3.7) | <0.0002 |
Additional efficacy data are available from a randomized, open-label, multicenter phase II study [JapicCTI-121850] conducted in Japanese patients with translocation-related sarcoma (TRS), most common being myxoid round- cell liposarcoma (n=24), synovial sarcoma (n=18), mesenchymal chondrosarcoma (n=6), and extraskeletal Ewing sarcoma/PNET, alveolar soft part sarcoma, alveolar rhabdomyosarcoma and clear cell sarcoma (n=5 each). The study assessed the efficacy and safety of trabectedin vs. best supportive care (BSC) as second-line or later therapy for patients with advanced TRS unresponsive or intolerant to standard chemotherapy regimen. The patients received the trabectedin dose of 1.2 mg/m2 recommended for Japanese patients [1.2 mg/m2 once every 3 weeks (q3wk 24-h)]. A total of 76 Japanese patients were enrolled in the study, among which 73 patients were included in the final analysis set. The study primary endpoint was PFS, that showed a statistically significant improvement in favour of trabectedin over BSC [HR=0.07; 95% CI: 0.03-0.16; p<0.0001], with a median PFS in the trabectedin group of 5.6 months [95% CI: 4.1-7.5] and in the BSC group of 0.9 months [95% CI: 0.7- 1.0]. The secondary endpoints included objective response analysed using the RECIST and Choi criteria. Using the RECIST criteria the ORR among patients treated with trabectedin was 3 (8.1%; 95% CI: 1.7.21.9%) and 0 (0%, 95% CI: 0.0-9.7%) among patients treated with best supportive care, while the CBR was 24 (64.9%, 95% CI: 47.5-79.9%) versus 0 (0%, 95% CI: 0.0-9.7%), respectively. Using the Choi criteria the ORR among patients treated with trabectedin was 4 (10.8%; 95% CI: 3.0-25.4%) and 0 (0%, 95% CI: 0.0-9.7%) among patients treated with best supportive care, while the CBR was 7 (18.9%, 95% CI: 8.0-35.2%) versus 0 (0%, 95% CI: 0.0-9.7%), respectively.
The efficacy of Yondelis/PLD combination in relapsed ovarian cancer is based on ET743-OVA-301, a randomized phase 3 study of 672 patients who received either trabectedin (1.1 mg/m2) and PLD (30 mg/m2) every 3 weeks or PLD (50 mg/m2) every 4 weeks. The primary analysis of progression free survival (PFS) was performed in 645 patients with measurable disease and assessed by independent radiology review. Treatment with the combination arm resulted in a 21% risk reduction for disease progression compared to PLD alone (HR=0.79, CI: 0.65-0.96, p=0.0190). Secondary analyses of PFS and response rate also favoured the combination arm. The results of the main efficacy analyses are summarised in the table below:
Efficacy analyses from ET743-OVA-301
| | Yondelis+PLD | PLD | Hazard/Odds ratio | p-value |
| Progression Free Survival |
| Independent radiology review, measurable disease * | n=328 | n=317 | | |
| Median PFS (95% CI) (months) | 7.3 (5.9-7.9) | 5.8 (5.5-7.1) | 0.79 (0.65-0.96) | 0.0190 a |
| 12 months PFS rate (95% CI) (%) | 25.8 (19.7-32.3) | 18.5 (12.9-24.9) | | |
| Independent oncology review, all randomised | n=336 | n=335 | | |
| Median PFS (95% CI) (months) | 7.4 (6.4-9.2) | 5.6 (4.2-6.8) | 0.72 (0.60-0.88) | 0.0008 a |
| Overall Survival (Final analysis - n=522 events) |
| All randomised | n=337 | n=335 | | |
| Median OS (95% CI) (months) | 22.2 (19.3-25.0) | 18.9 (17.1-21.5) | 0.86 (0.72-1.02) | 0.0835 a |
| Overall survival in platinum-sensitive population (Final analysis n=316 events) |
| | n=218 | n=212 | | |
| Median OS (95% CI) (months) | 27.0 (24.1-31.4) | 24.1 (20.9-25.9) | 0.83 (0.67-1.04) | 0.1056 a |
| Overall Response Rate (ORR) |
| Independent radiology review, all randomised | n=337 | n=335 | | |
| ORR (95% CI) (%) | 27.6 (22.9-32.7) | 18.8 (14.8-23.4) | 1.65 (1.14-2.37) | 0.0080 b |
* Primary efficacy analysis
a Log rank test
b Fisher's test
Based on independent oncology review, patients with platinum-free interval (PFI) < 6 months (35% in Yondelis+PLD and 37% in PLD arm) had similar PFS in the two arms with both showing median PFS of 3.7 months (HR=0.89, CI: 0.67-1.20). In patients with PFI ≥ 6 months (65% in Yondelis+PLD and 63% in PLD arm), median PFS was 9.7 months in the Yondelis+PLD arm compared with 7.2 months in the PLD monotherapy arm (HR=0.66, CI: 0.52-0.85).
In the final analysis, the effect of the Yondelis+PLD combination vs. PLD alone on overall survival was more pronounced in patients with PFI ≥ 6 months (platinum-sensitive population: 27.0 vs. 24.1 months, HR=0.83, CI: 0.67-1.04) than in those with PFI < 6 months (platinum-resistant population: 14.2 vs. 12.4 months, HR=0.92, CI: 0. 70-1.21).
The benefit in OS with Yondelis plus PLD was not due to the effect of subsequent therapies, which were well balanced between the two treatment arms.
In the multivariate analyses including PFI, treatment effect on overall survival was statistically significant favouring the Yondelis+PLD combination over PLD alone (all randomised: p=0.0285; platinum-sensitive population: p=0.0319).
No statistically significant differences were found between treatment arms in global measures of Quality of Life.
The Yondelis+PLD combination in relapsed ovarian cancer also was evaluated in study ET743-OVC-3006, a phase 3 study in which women with ovarian cancer after failure of a second platinum-containing regimen were randomized to Yondelis (1.1 mg/m2) and PLD (30 mg/m2) every 3 weeks or PLD (50 mg/m2) every 4 weeks. Study participants were required to be platinum sensitive (PFI ≥ 6 months) following their first platinum-containing regimen and have a complete or partial response to a second line platinum-based chemotherapy (without PFI restrictions) meaning that these patients could be either platinum-sensitive (PFI ≥ 6 months) or platinum-resistant (PFI < 6 months) following their second platinum-containing regimen. A post hoc analysis determined that 42% of enrolled subjects were platinum-resistant (PFI < 6 months) following their last platinum-containing regimen.
The primary endpoint of study ET743-OVC-3006 was OS and secondary endpoints included PFS and ORR. The study was sized to enrol approximately 670 patients in order to observe 514 deaths to detect a HR of 0.78 for OS with 80% power given a two-sided significance level of 0.05 spread across two planned analyses on OS, at interim (60% or 308/514 deaths) and final analysis (514 deaths). Two early unscheduled futility analyses were performed at the request of the Independent Data Monitoring Committee (IDMC). Following the second futility analysis performed at 45% of planned events (232/514 deaths), the IDMC recommended discontinuing the study due to (1) futility of the primary analysis on OS and (2) excessive risk based on imbalance of adverse events not in favour of Yondelis+PLD. At early termination of the study, 9% (52/572 treated) of subjects stopped treatment, 45% (260/576 randomized) stopped follow-up, and 54% (310/576 randomized) were censored from OS assessment, precluding reliable estimates of PFS and OS endpoints.
No data are available comparing Yondelis+PLD to a platinum-based regimen in platinum-sensitive patients.
Paediatric population
In SAR-2005 phase I-II study, a total of 50 paediatric patients with rhabdomyosarcoma, Ewing sarcoma or non rhabdomyosarcoma soft tissue sarcoma were enrolled. Eight patients were treated with a dose of 1.3 mg/m2 and 42 with 1.5 mg/m2. Trabectedin was administered as a 24-hour intravenous infusion every 21 days. Forty patients were fully evaluable for response. One partial response (PR) centrally confirmed was observed: overall RR: 2.5% CI95% (0.1%-13.2%). The PR corresponded to a patient with an alveolar rhabdomyosarcoma. Duration of the response was 6.5 months No responses were observed for Ewing sarcoma and NRSTS, [RR: 0% CI95% (0%-30.9%)]. Three patients achieved stable disease (one with rhabdomyosarcoma after 15 cycles, one with spindle cell sarcoma after 2 cycles, and one with Ewing sarcoma after 4 cycles.
Adverse reactions, included reversible elevation of liver enzymes and haematological events; in addition, fever, infection, dehydration and thrombosis/embolism were also reported.