221 Lurbinectedin (PM01183) in Combination with Gemcitabine in Patient-Derived, Pancreatic Ductal Adenocarcinoma (PDA) Xenografts

Poster Session – Natural Products and Marine Compounds breast and platinum-resistant/refractory ovarian) clinical evaluation. In vitro studies demonstrate that lurbinectedin causes delayed progression of S phase and cycle arrest in G2 M. Also, lurbinectedin was 3−4 time less potent in NER deficient cells whereas it was 100 time more potent in HR deficient cells. The in vivo antitumor activity of lurbinectedin was evaluated in human ovarian carcinoma models, growing subcutaneously (OCX) or in the peritoenal cavity (IPX). Material and Methods: The in vivo pharmacological behavior of lurbinectedin was evaluated in M5076 (murine reticulosarcoma), MN-MCA1 (murine fibrosarcoma), 2 human OCX (HOC 18 and MNB-PTX-1) and 2 IPX (HOC8 and HOC22). Lurbinectedin was given i.v. at 0.2 mg/kg/day on days 0, 7, 14 (q7d×3). The antitumor effect was calculated either by T/C (as a percentage of the change in tumor size for treated [T] and placebo [C]) or by the increase of like span (ILS) (as 100·[(T − C)/C], where ‘T’ and ‘C’ are the median survival time of the treated and placebo); treatment-related anti-metastic activity was also evaluated. Results: In M5076 lurbinectedin was only marginally active (T/C, 73.4%) against the primary tumor whereas in MN-MCA1 demonstrated a good antitumor activity (best T/C 15%). In both tumor models lurbinectedin produced a striking antimetastatic effect (p < 0.001). Lurbinectedin treatment resulted in no antitumor activity in the MNB-PTX-1 model. In animals bearing OCX HOC18 tumors, lurbinectedin treatment induced a strong and long-lasting antitumor effect (minimal T/C, 13% Day 16). Tumor volume were reduced (P < 0.01) compared to placebo on days 10−17. Also, lurbinectedin treatment reduced tumor growth rate: all animals were sacrificed due to tumor volume on Day 63, later than placebo (Day 15). Lurbinectedin treatment of HOC8 IPX xenografts resulted in (P < 0.05) antitumor activity compared to untreated animals (ILS % of 140.0). Eight out of 9 of mice bearing HOC22 IPX tumors and treated with lurbinectedin survived 4 months after the death of the last placebo-treated animal and, then considered as tumor-free. Conclusions: The in vivo antitumor effect of lurbinectedin was demonstrated in a panel of human and murine experimental models, characterized by different behaviors and drug sensitivity. 221 POSTER Lurbinectedin (PM01183) in Combination with Gemcitabine in Patient-Derived, Pancreatic Ductal Adenocarcinoma (PDA) Xenografts 1 P.P. Lopez-Casas ´ , M. Hidalgo1 , M.J. Guillen ´ 2 , F. Sarno1 , O. Cataluna ˜ 2, M. Palomares2 , C. Cuevas2 , P. Aviles2 . 1 Centro Nacional de ´ Investigaciones Oncologicas, Hospital de Madrid, Madrid, Spain; 2 PharmaMar S.A.U., R&D, Colmenar Viejo (Madrid), Spain

Background: Lurbinectedin (PM01183) is a new synthetic tetrahydroisoquinoline alkaloid that exerts a wide antitumor activity through minor groove DNA-binding and has shown clinical activity in pancreatic and platinum-resistant ovarian cancer. Currently, the clinical development of lurbinectedin includes ongoing phase II single agent trials (pancreas, breast and platinum-resistant/refractory ovarian), phase I trials in combination with doxorubicin and gemcitabine (GEM) as well as in advanced acute leukemia. Results from the phase I trial of lurbinectedin and GEM demonstrated that the combination was clinically feasible showing an acceptable safety profile and a promising antitumor activity. Here, we report the results of the in vivo antitumor activity of lurbinectedin combined with GEM in several patientderived pancreatic ductal adenocarcinoma (PDA) xenografts that have the potential to better represent the biology of human PDA. Material and Methods: Athymic female nu/nu mice were subcutaneously implanted with 6 different patient-derived PDA tumors, namely Panc026, Panc-265, Panc-354, Panc-291, JH-010 and JH-024. When tumors reached ca. 400 mm3 , tumor bearing animals (N=6−10/group) were randomly allocated into experimental groups: lurbinectedin (0.18 mg/kg), GEM (180 mg/kg), lurbinectedin + GEM (0.18+180 mg/kg) or placebo groups. Treatments were administered for 5 consecutive weeks (q7d×5; days 0, 7, 14, 21, 28). Antitumor effect was calculated using DT/DC (%), defined as a percentage of the change in tumor size for treated (T) and placebo (C) groups during the placebo-treated survival time (D). Results: The combination lurbinectedin and GEM produced lower DT/DC values than the more active single agent in 5 out of 6 models assayed. Tumor

% DT/DC (D) Lurbinectedin

GEM

Lurbinectedin + GEM

Panc-026 Panc-265 Panc-354 Panc-291 JH-010 JH0−24

11 (41) 41 (28) 50 (25) 89 (24) 65 (42) 6 (56)

61 (41) 73 (28) 22 (25) 71 (24) 2 (42) 65 (56)

4 (41) 12 (28) 5 (25) 33 (24) 8 (42) 3 (56)

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During the treatment with the combination lurbinectedin and GEM complete remissions (CR) of tumors were also seen in animals bearing the following xenografts: Panc-026 (9 CR/10 mice), Panc-265 (1 CR/7 mice), Panc-354 (4 CR/6 mice) and JH-024 (5 CR/10 mice). Conclusion: The combination of lurbinectedin and GEM demonstrated significant in vivo antitumor activity in patient-derived xenografts of human PDA. In the majority of cases the combination showed better activity compared to single compounds. 222 POSTER Lurbinectedin (PM01183): Pharmacokinetics/Pharmacodynamic (PK/PD) Properties in Pancreas, Ovarian and NSCLC Xenografts 2 P. Aviles1 , M.V. Cespedes ´ , M.J. Guillen ´ 3 , P. Alamo2 , A. Bishop3 , A. Gallardo2 , T. Pernice3 , R. Mangues2 , C. Cuevas3 . 1 PharmaMar S.A.U, R&D, Colmenar Viejo (Madrid), Spain; 2 Institut d‘Investigacions ` Biomediques Sant Pau, Hospital de Sant Pau and CIBER de Bioingenieria Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain; 3 PharmaMar S.A.U., R&D, Colmenar Viejo (Madrid), Spain

Background: Lurbinectedin (PM01183) is a new synthetic tetrahydroisoquinoline alkaloid, currently undergoing clinical development as a single agent in pancreas, breast and platinum-resistant/refractory ovarian cancer patients (phase II). It is also under evaluation in advanced acute leukemia and in combinations with doxorubicin and gemcitabine (phase I). In vitro, lurbinectedin induces antitumor activity through binding to the minor groove of DNA, producing lurbinectedin-DNA adducts, double-strand breaks (DSBs), activation of the DNA replication checkpoints, S-phase delay/arrest and, finally apoptotic-mediated cell death. The intratumor pharmacokinetics (PK) and pharmacodynamic (PD) properties (DSBs, apoptosis and antitumor activity) following administration of lurbinectedin in mice bearing pancreas, ovarian and NSCLC xenografts are presented here. Material and Methods: Athymic mice were implanted with SW1990 (pancreas), A2780 (ovarian) or H460 (NSCLC) cancer cells. Tumor bearing (ca. 300 mm3 ) animals were allocated into PK or PD groups. All animals received a single iv dose of lurbinectedin at 0.18 mg/kg. In the PK group, tumor samples (N=3−4/time) were collected at different times and up to 24 h post-dosing and analysed for lurbinectedin concentration by LC/MSMS. In the PD group, 12 and 48 h post-dosing, tumors samples (SW-1990, A2780 and H460) were collected and processed for H&E and g-H2AX stainings. Separate groups of tumors bearing animals (N=8−10/group) were treated and the antitumor activity was followed by the change in tumor volume for lurbinectedin- or placebo-treated groups on Day 7 (D7). Results: After the iv administration of 0.18 mg/kg, lurbinectedin was detected in the 3 xenografted tumors up to 24 h post-dosing. The area under curve (AUC0−24h ) for lurbinectedin in the tumors assayed ranged from 34 to 67 ng·hr/g, with a terminal half-life of ca. 15 h. Compared to placebo, lurbinectedin-treated tumors had increased (6.8-, 2.1- and 3.0-fold in SW-1990, A2780 and H460 tumors, respectively) g-H2AX levels (at 12-h), increased (1.7-, 1.6- and 3.5-fold in SW-1990, A2780 and H460 tumors, respectively) number of dead bodies (at 48-h) and statistically (P < 0.05) reduced tumor sizes (on D7). Conclusion: In mice xenografted with pancreas, ovarian or NSCLC tumors, lurbinectedin was widely distributed in tumors, induced double-strand breaks, apoptosis and, altogether a significant antitumor in vivo effect. 223 POSTER Lurbinectedin (PM01183) Synergizes with Gemcitabine in NSCLC, Ovarian and Pancreas Tumor Xenografts 1 2 R. Mangues1 , M.V. Cespedes ´ , M.J. Guillen ´ 2 , P. Alamo1 , R. Lopez ´ , A. Gallardo1 , P. Nunez ˜ 2 , C. Cuevas2 , P. Aviles2 . 1 Institut d‘Investigacions ` Biomediques Sant Pau, Hospital de Sant Pau and CIBER de Bioingenieria Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, 2 Spain; PharmaMar S.A.U., R&D, Colmenar Viejo (Madrid), Spain

Background: Lurbinectedin (PM01183), a new synthetic tetrahydroisoquinoline alkaloid, is currently in pancreatic, breast and platinumresistant/refractory ovarian (phase II) and in advanced acute leukemia or combined with doxorubicin or gemcitabine (phase I). In vitro, lurbinectedin binds to the minor groove of DNA, produces double-strand breaks, activation of the DNA replication checkpoints, S-phase delay/arrest and, finally an apoptotic-mediated cell death. The pharmacological effects (apoptosis and antitumor activity) after the administration of lurbinectedin, gemcitabine or lurbinectedin + gemcitabine in mice bearing xenografts of NSCLC, ovarian and pancreas tumors are presented here. Material and Methods: Athymic mice were implanted with SW1990 (pancreas), A2780 (ovarian) or H460 (NSCLC) cancer cells. Mice bearing tumors (ca. 150 mm3 ) were allocated to 13 groups (N = 6−8/