Safety and immunogenicity of shorter interval schedules of the novel oral poliovirus vaccine type 2 in infants: a phase 3, randomised, controlled, non-inferiority study in the Dominican Republic

BACKGROUND

The novel oral poliovirus vaccine type 2 (nOPV2) is now authorised by a WHO emergency use listing and widely distributed to interrupt outbreaks of circulating vaccine-derived poliovirus type 2. As protection of vulnerable populations, particularly young infants, could be facilitated by shorter intervals between the two recommended doses, we aimed to assess safety and non-inferiority of immunogenicity of nOPV2 in 1-week, 2-week, and 4-week schedules.

METHODS

In this phase 3, open-label, randomised trial, healthy, full-term, infants aged 6-8 weeks from a hospital or a clinic in the Dominican Republic were randomly allocated (1:1:1 ratio) using a pre-prepared, computer-generated randomisation schedule to three groups to receive two doses of nOPV2 immunisations with a 1-week interval (group A), 2-week interval (group B), or 4-week interval (group C). The nOPV2 vaccine was given at a 0·1 mL dose and contained at least 105 50% cell culture infective dose. Neutralising antibodies against poliovirus types 1, 2, and 3 were measured before each immunisation and 4 weeks after the second dose. The primary outcome was the type 2 seroconversion rate 28 days after the second dose, and the non-inferiority margin was defined as a lower bound 95% CI of greater than -10%. Safety and reactogenicity were assessed through diary cards completed by the parent or guardian. The trial is registered with ClinicalTrials.gov, NCT05033561.

FINDINGS

We enrolled 905 infants between Dec 16, 2021, and March 28, 2022. 872 infants were included in the per-protocol analyses: 289 in group A, 293 in group B, and 290 in group C. Type 2 seroconversion rates were 87·5% (95% CI 83·2 to 91·1) in group A (253 of 289 participants), 91·8% (88·1 to 94·7) in group B (269 of 293 participants), and 95·5% (92·5 to 97·6) in group C (277 of 290 participants). Non-inferiority was shown for group B compared with group C (difference in rates -3·7; 95% CI -7·9 to 0·3), but not for group A compared with group C (-8·0; -12·7 to -3·6). 4 weeks after the second nOPV2 dose, type 2 neutralising antibodies increased in all three groups such that over 95% of each group was seroprotected against polio type 2, although final geometric mean titres tended to be highest with longer intervals between doses. Immunisation with nOPV2 was well tolerated with no causal association to vaccination of any severe or serious adverse event; one death from septic shock during the study was unrelated to the vaccine.

INTERPRETATION

Two nOPV2 doses administered 1 week or 2 weeks apart from age 6 weeks to 8 weeks were safe and immunogenic. Immune responses after a 2-week interval were non-inferior to those after the standard 4-week interval, but marked responses after a 1-week interval suggest that schedules with an over 1-week interval can be used to provide flexibility to campaigns to improve coverage and hasten protection during circulating vaccine-derived poliovirus type 2 outbreaks.

FUNDING

Bill & Melinda Gates Foundation.

Effectiveness of the Fiocruz recombinant ChadOx1-nCoV19 against variants of SARS-CoV-2 in the Municipality of Botucatu-SP

Introduction

As the COVID-19 pandemic progresses, rapidly emerging variants of concern raise fears that currently licensed vaccines may have reduced effectiveness against these new strains. In the municipality of Botucatu, São Paulo State, Brazil, a mass vaccination campaign using ChadOx1-nCoV19 was initiated on 16th of May 2021, targeting people 18-60 years old. Two vaccine doses were offered 12 weeks apart, with the second delivered on 8th of August, 2021. This setting offered a unique opportunity to assess the effectiveness of two ChadOx1-nCoV19 doses in a real-life setting.

Materials and methods

Data on testing, hospitalization, symptoms, demographics, and vaccination were obtained from the Hospital das Clínicas da Faculdade de Medicina de Botucatu. A test-negative study design was employed; whereby the odds of being vaccinated among cases vs controls were calculated to estimate vaccine effectiveness (VE; 1-OR). All individuals aged 18-60 who received a PCR test after the 16th of May and were unvaccinated prior to this date were included in the analysis until the study ended in mid-November 2021.

Results

77,683 citizens of Botucatu aged 18-60 received the first dose, and 74,051 received a second ChadOx1-nCoV19 dose 12 weeks later for a vaccination coverage of 84.2 and 80.2%, respectively. Of 7.958 eligible PCR tests, 2.109 were positive and 5.849 negative. The VE against any symptomatic infection was estimated at 39.2%, 21 days after dose 1, and 74.5%, 14 days after dose 2. There were no COVID-19-related hospitalizations or deaths among the 74,051 fully vaccinated individuals. The VE against severe disease was estimated at 70.8 and 100% after doses 1 and 2, respectively. 90.5% of all lineages sequenced between doses 1 and 2 (16th of May-7th of August) were of the Gamma variant, while 83.0% were of the Delta variant during the second period after dose 2 (8th of August-18th of November).

Discussion

This observational study found the effectiveness of ChadOx1-nCoV19 to be 74.5% against COVID-19 disease of any severity, comparable to the efficacy observed in clinical trials (81.3% after dose 2), despite the dominance of the Gamma and Delta VoCs. No COVID-19-related hospitalizations or deaths in fully vaccinated individuals were reported.

Fecal shedding of two novel live attenuated oral poliovirus type 2 vaccines candidates by healthy bOPV/IPV-vaccinated infants: two randomized clinical trials

Background

Primary intestinal immunity through viral replication of live oral vaccine is key to interrupt poliovirus transmission. We assessed viral fecal shedding from infants administered Sabin monovalent poliovirus type 2 vaccine (mOPV2) or low and high doses of 2 novel OPV2 (nOPV2) vaccine candidates.

Methods

In 2 randomized clinical trials in Panama, a control mOPV2 study (October 2015 to April 2016) and nOPV2 study (September 2018 to October 2019), 18-week-old infants vaccinated with bivalent oral poliovirus vaccine/inactivated poliovirus vaccine received 1 or 2 study vaccinations 28 days apart. Stools were assessed for poliovirus RNA by polymerase chain reaction (PCR) and live virus by culture for 28 days postvaccination.

Results

Shedding data were available from 621 initially reverse-transcription PCR–negative infants (91 mOPV2, 265 nOPV2-c1, 265 nOPV2-c2 recipients). Seven days after dose 1, 64.3% of mOPV2 recipients and 31.3%–48.5% of nOPV2 recipients across groups shed infectious type 2 virus. Respective rates 7 days after dose 2 decreased to 33.3% and 12.9%–22.7%, showing induction of intestinal immunity. Shedding of both nOPV2 candidates ceased at similar or faster rates than mOPV2.

Conclusions

Viral shedding of either nOPV candidate was similar or decreased relative to mOPV2, and all vaccines showed indications that the vaccine virus was replicating sufficiently to induce primary intestinal mucosal immunity.

A phase 1b study of novel immunogenic cell death inducer PT-112 plus PD-L1 inhibitor avelumab in metastatic castrate-resistant prostate cancer (mCRPC) patients

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Background: PT-112 is a novel pyrophosphate-platinum conjugate that induces immunogenic cell death, reaches highest concentrations in bone (osteotropism), and synergizes with immune checkpoint inhibitors (ICIs) in preclinical models. Phase I studies in solid tumors, as monotherapy and in combination with PD-L1 inhibitor avelumab (“PAVE”), as well as in multiple myeloma as monotherapy have demonstrated that PT-112 is well-tolerated and active. We present updated safety and exploratory efficacy findings in a mCRPC sub-population treated with PAVE, including a cohort of patients at a lower-frequency dosing schedule. Methods: A total of 32 mCRPC patients (pts) received 800 mg of avelumab on days 1 and 15 of a 28-day cycle, of whom 18 received PT-112 on days 1, 8 and 15 at 200mg/m2 (n = 17) or 150 mg/m2 (n = 1); a separate cohort of 14 received PT-112 on days 1 and 15 at 300 mg/m2 (n = 13) or 200mg/m2 (n = 1). Results: Median age was 68 (range 47-87) and number of prior lines of therapy (Tx) was 7 (2-12), including prior platinum-containing therapy in 11 (34%) and ICI Tx in 9 pts (28%). Baseline grade 2 anemia was seen in 7 (22%) pts. The most common treatment-related adverse events (TRAEs) were anemia (47%) and thrombocytopenia (41%); 23 pts (72%) had ≥1 grade 3-4 TRAE, with no cases of bleeding, sepsis, or grade 5 TRAEs. Antitumor effects included 8 (25%) pts with a PSA reduction of ≥50% (PSA50); 5 (16%) were maintained through ≥1 follow-up. Of ten pts with RECIST-measurable disease, 3 had tumor volume reductions, one with a confirmed partial response (PR). Twenty-four (75%) pts experienced a reduction in serum alkaline phosphatase (ALP) (median reduction 15%), and improvement in patient-reported pain and quality of life was observed. For the 13 pts given 300 mg/m2 PT-112 bi-weekly, 7 (54%) had prior platinum-containing Tx and 4 (31%) had baseline grade 2 anemia. The most common TRAEs were anemia (69%) and thrombocytopenia (54%), with 11 (85%) pts having ≥1 grade 3-4 TRAE. Four pts (31%) had PSA50 reductions; 3 (23%) were maintained through ≥1 follow-up. Conclusions: PAVE is safe and generally well tolerated in mCRPC patients at the doses and schedules tested, providing meaningful antitumor effects in heavily pre-treated patients, including tumor volume, PSA and ALP reductions. Reductions in ALP may be indicative of anti-cancer activity at bone sites of disease. Although the sample sizes are small, the frequency of confirmed PSA50 responses and of grade 3-4 TRAEs was slightly higher in the group receiving biweekly 300 mg/m2 PT-112, and higher rates of TRAEs may be explained by higher baseline anemia and/or prior platinum Tx. Further clinical investigation of the combination of PT-112 plus ICIs in a less heavily pre-treated mCRPC population is warranted. A phase 2 study of PT-112 monotherapy in mCRPC is ongoing. Clinical trial information: NCT03409458.

Safety and immunogenicity of inactivated poliovirus vaccine schedules for the post-eradication era: a randomised open-label, multicentre, phase 3, non-inferiority trial

BACKGROUND

Following the global eradication of wild poliovirus, countries using live attenuated oral poliovirus vaccines will transition to exclusive use of inactivated poliovirus vaccine (IPV) or fractional doses of IPV (f-IPV; a f-IPV dose is one-fifth of a normal IPV dose), but IPV supply and cost constraints will necessitate dose-sparing strategies. We compared immunisation schedules of f-IPV and IPV to inform the choice of optimal post-eradication schedule.

METHODS

This randomised open-label, multicentre, phase 3, non-inferiority trial was done at two centres in Panama and one in the Dominican Republic. Eligible participants were healthy 6-week-old infants with no signs of febrile illness or known allergy to vaccine components. Infants were randomly assigned (1:1:1:1, 1:1:1:2, 2:1:1:1), using computer-generated blocks of four or five until the groups were full, to one of four groups and received: two doses of intradermal f-IPV (administered at 14 and 36 weeks; two f-IPV group); or three doses of intradermal f-IPV (administered at 10, 14, and 36 weeks; three f-IPV group); or two doses of intramuscular IPV (administered at 14 and 36 weeks; two IPV group); or three doses of intramuscular IPV (administered at 10, 14, and 36 weeks; three IPV group). The primary outcome was seroconversion rates based on neutralising antibodies for poliovirus type 1 and type 2 at baseline and at 40 weeks (4 weeks after the second or third vaccinations) in the per-protocol population to allow non-inferiority and eventually superiority comparisons between vaccines and regimens. Three co-primary outcomes concerning poliovirus types 1 and 2 were to determine if seroconversion rates at 40 weeks of age after a two-dose regimen (administered at weeks 14 and 36) of intradermally administered f-IPV were non-inferior to a corresponding two-dose regimen of intramuscular IPV; if seroconversion rates at 40 weeks of age after a two-dose IPV regimen (weeks 14 and 36) were non-inferior to those after a three-dose IPV regimen (weeks 10, 14, and 36); and if seroconversion rates after a two-dose f-IPV regimen (weeks 14 and 36) were non-inferior to those after a three-dose f-IPV regimen (weeks 10, 14, and 36). The non-inferiority boundary was set at -10% for the lower bound of the two-sided 95% CI for the seroconversion rate difference.. Safety was assessed as serious adverse events and important medical events. This study is registered on ClinicalTrials.gov, NCT03239496.

FINDINGS

From Oct 23, 2017, to Nov 13, 2018, we enrolled 773 infants (372 [48%] girls) in Panama and the Dominican Republic (two f-IPV group n=217, three f-IPV group n=178, two IPV group n=178, and three IPV group n=200). 686 infants received all scheduled vaccine doses and were included in the per-protocol analysis. We observed non-inferiority for poliovirus type 1 seroconversion rate at 40 weeks for the two f-IPV dose schedule (95·9% [95% CI 92·0-98·2]) versus the two IPV dose schedule (98·7% [95·4-99·8]), and for the three f-IPV dose schedule (98·8% [95·6-99·8]) versus the three IPV dose schedule (100% [97·9-100]). Similarly, poliovirus type 2 seroconversion rate at 40 weeks for the two f-IPV dose schedule (97·9% [94·8-99·4]) versus the two IPV dose schedule (99·4% [96·4-100]), and for the three f-IPV dose schedule (100% [97·7-100]) versus the three IPV dose schedule (100% [97·9-100]) were non-inferior. Seroconversion rate for the two f-IPV regimen was statistically superior 4 weeks after the last vaccine dose in the 14 and 36 week schedule (95·9% [92·0-98·2]) compared with the 10 and 14 week schedule (83·2% [76·5-88·6]; p=0·0062) for poliovirus type 1. Statistical superiority of the 14 and 36 week schedule was also found for poliovirus type 2 (14 and 36 week schedule 97·9% [94·8-99·4] vs 10 and 14 week schedule 83·9% [77·2-89·2]; p=0·0062), and poliovirus type 3 (14 and 36 week schedule 84·5% [78·7-89·3] vs 10 and 14 week schedule 73·3% [65·8-79·9]; p=0·0062). For IPV, a two dose regimen administered at 14 and 36 weeks (99·4% [96·4-100]) was superior a 10 and 14 week schedule (88·9% [83·4-93·1]; p<0·0001) for poliovirus type 2, but not for type 1 (14 and 36 week schedule 98·7% [95·4-99·8] vs 10 and 14 week schedule 95·6% [91·4-98·1]), or type 3 (14 and 36 week schedule 97·4% [93·5-99·3] vs 10 and 14 week schedule 93·9% [89·3-96·9]). There were no related serious adverse events or important medical events reported in any group showing safety was unaffected by administration route or schedule.

INTERPRETATION

Our observations suggest that adequate immunity against poliovirus type 1 and type 2 is provided by two doses of either IPV or f-IPV at 14 and 36 weeks of age, and broad immunity is provided with three doses of f-IPV, enabling substantial savings in cost and supply. These novel clinical data will inform global polio immunisation policy for the post-eradication era.

FUNDING

Bill & Melinda Gates Foundation.

Safety and immunogenicity of two novel type 2 oral poliovirus vaccine candidates compared with a monovalent type 2 oral poliovirus vaccine in children and infants: two clinical trials

BACKGROUND

Continued emergence and spread of circulating vaccine-derived type 2 polioviruses and vaccine-associated paralytic poliomyelitis from Sabin oral poliovirus vaccines (OPVs) has stimulated development of two novel type 2 OPV candidates (OPV2-c1 and OPV2-c2) designed to have similar immunogenicity, improved genetic stability, and less potential to reacquire neurovirulence. We aimed to assess safety and immunogenicity of the two novel OPV candidates compared with a monovalent Sabin OPV in children and infants.

METHODS

We did two single-centre, multi-site, partly-masked, randomised trials in healthy cohorts of children (aged 1-4 years) and infants (aged 18-22 weeks) in Panama: a control phase 4 study with monovalent Sabin OPV2 before global cessation of monovalent OPV2 use, and a phase 2 study with low and high doses of two novel OPV2 candidates. All participants received one OPV2 vaccination and subsets received two doses 28 days apart. Parents reported solicited and unsolicited adverse events. Type 2 poliovirus neutralising antibodies were measured at days 0, 7, 28, and 56, and stool viral shedding was assessed up to 28 days post-vaccination. Primary objectives were to assess safety in all participants and non-inferiority of novel OPV2 day 28 seroprotection versus monovalent OPV2 in infants (non-inferiority margin 10%). These studies were registered with ClinicalTrials.gov, NCT02521974 and NCT03554798.

FINDINGS

The control study took place between Oct 23, 2015, and April 29, 2016, and the subsequent phase 2 study between Sept 19, 2018, and Sept 30, 2019. 150 children (50 in the control study and 100 of 129 assessed for eligibility in the novel OPV2 study) and 684 infants (110 of 114 assessed for eligibility in the control study and 574 of 684 assessed for eligibility in the novel OPV2 study) were enrolled and received at least one study vaccination. Vaccinations were safe and well tolerated with no causally associated serious adverse events or important medical events in any group. Solicited and unsolicited adverse events were overwhelmingly mild or moderate irrespective of vaccine or dose. Nearly all children were seroprotected at baseline, indicating high baseline immunity. In children, the seroprotection rate 28 days after one dose was 100% for monovalent OPV2 and both novel OPV2 candidates. In infants at day 28, 91 (94% [95% CI 87-98]) of 97 were seroprotected after receiving monovalent OPV2, 134 (94% [88-97]) of 143 after high-dose novel OPV2-c1, 122 (93% [87-97]) of 131 after low-dose novel OPV2-c1, 138 (95% [90-98]) of 146 after high-dose novel OPV2-c2, and 115 (91% [84-95]) of 127 after low-dose novel OPV2-c2. Non-inferiority was shown for low-dose and high-dose novel OPV2-c1 and high-dose novel OPV2-c2 despite monovalent OPV2 recipients having higher baseline immunity.

INTERPRETATION

Both novel OPV2 candidates were safe, well tolerated, and immunogenic in children and infants. Novel OPV2 could be an important addition to our resources against poliovirus given the current epidemiological situation.

FUNDING

Fighting Infectious Diseases in Emerging Countries and Bill & Melinda Gates Foundation.

PT-112 in advanced metastatic castrate-resistant prostate cancer (mCRPC), as monotherapy or in combination with PD-L1 inhibitor avelumab: Findings from two phase I studies

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Background: PT-112, the first pyrophosphate conjugate in Phase I/II clinical development, induces robust immunogenic cell death and is osteotropic, prompting study in mCRPC during Phase I. We report safety and efficacy findings in the mCRPC sub-population given PT-112 monotherapy (NCT02266745) or in combination with avelumab (“PAVE”) (NCT03409458, ongoing). Methods: Patients (pts) received PT-112 days 1, 8, 15 of a 28d cycle; pts on the PAVE combination also received 800 mg avelumab days 1 and 15; all enrolled during dose escalation or at PT-112 doses previously deemed safe. Pts on therapy (Tx) for ≥2 cycles or who stopped Tx due to progressive disease or treatment-related adverse events (TRAEs) were evaluated for exploratory efficacy. Results: 10 pts on PT-112 (200-420 mg/m2) and 18 pts on PAVE (150-200 mg/m2 PT-112) were evaluable for safety. The most common PT-112 TRAEs were thrombocytopenia (70%, grade (Gr) ≤3) and fatigue (40%, Gr ≤2) with mono-Tx; nausea (50%, Gr ≤2) and fatigue (39%, Gr ≤2) with PAVE. Mono-Tx pts had 6.5 median prior lines of Tx; 2/7 pts with measurable disease (MD) had reductions in target lesions; prostate specific antigen (PSA) declined in 3/10 pts, 1 with ≥50% reduction; and serum alkaline phosphatase (ALP) reductions were seen in 9/10 pts. PAVE pts had 5.5 median prior lines of Tx; radiographic reductions were seen in 2/9 pts with MD; PSA declined in 6/14 pts, 3 with ≥50% decrease, with 1 responder progression free 11.3 months (microsatellite stable). An additional response is ongoing at 4 mos, with 93% PSA decrease and 48% reduction in target lesions (PIK3CBmut & PTEN loss). 13/14 pts with bone metastases had ALP reductions. Pain improvement, opioid cessation and improved performance status were noted in both cohorts. Conclusions: PT-112 was well-tolerated with evidence of efficacy in mCRPC as mono-Tx and in combination with avelumab in heavily pre-treated pts. Bone pain improvement and nearly universal observation of ALP reduction suggest marked therapeutic activity of PT-112 in bone metastases. Serologic / RECIST responses and prolonged disease control in multiple pts substantiate further development of PT-112 in mCRPC. Clinical trial information: NCT02266745, NCT03409458.

Phase II Study with High Doses of Epirubicin in Patients with Advanced Rectal Cancer

We tested the possible role of epirubicin, 100 to 130 mg/m2 administered i.v. every 3 weeks, in patients with advanced adenocarcinoma of the rectum untreated with chemotherapy. Sixteen of 17 entered cases were evaluable. No complete or partial responses were observed. The median time to progression was 6 weeks, and the median survival was 36 weeks. Reversible leukopenia was the major toxic side effect. The median epirubicin cumulative dose was 330 mg/m2; no patient had clinical cardiac toxicity. With no responses recorded in 16 evaluable patients, the activity of epirubicin in rectal cancer ranged between 0 and 18%, with 95% probability. Further studies with epirubicin in this tumor are not indicated.

A phase I study of PT-112 in advanced solid tumors

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Background: PT-112 is a novel platinum-pyrophosphate agent designed to avoid the toxicity and drug resistance mechanisms of conventional chemotherapy. Pre-clinical models show effects on multiple cell signaling components: p16 mediated G1/S cell cycle arrest; modulation of MDM2/p53 expression; extrinsic apoptosis initiation; and immunogenic cell death (ICD) induction. This Phase I first-in-human, multicenter, open label study assesses PT-112’s safety and pharmacokinetic (PK) profile in advanced solid tumor patients (pts), to determine the RP2D and signals of activity. Methods: Pts with advanced solid tumors and acceptable marrow / organ function received PT-112 IV over 1-hr on days 1, 8, and 15 every 4 wks in a 3+3 dose escalation design. Intra-subject escalation was allowed. PK samples from cycles 1-2 were analyzed by ICP-MS and LC-MS/MS. Results: 44 pts have been treated across dose levels (DL) from 12-300mg/m2. Cumulative dosing ranged from 1 to 60 infusions, and cumulative exposure from 96 to 5,244 mg/m2. PK parameters were dose proportional. Target Cmax and AUC levels were achieved, with constant VD. DLTs were observed at 150mg/m2 (G3 pancytopenia); 250mg/m2 (G2 renal injury in a cervical ca pt with hydro-nephrosis); and 300mg/m2 (G3 rash). The most common treatment-related AEs were G1-2 fatigue (26% pts), nausea (23%), vomiting (14%), constipation (12%), and diarrhea (12%). Numerous signals of activity were observed at DLs ≥ 125mg/m2. These include a confirmed PR in a NSCLC pt with 6 prior lines of therapy and no response to TKI inhibition or PD-1 blockade; PFS > 6 months (7-18 months) in 3 pts; metabolic response via PET scan in bone and liver mets (basal cell and pancreatic ca.); biomarker responses in ovarian and prostate ca.; and nodal/metastatic volumetric reduction in 3 pts. Conclusions: PT-112 is a well-tolerated novel agent with a pleiotropic mode of action and feasibility for long-term and combination treatment. Numerous signals of anti-cancer efficacy in heavily pre-treated pts suggest lack of cross-resistance with conventional agents. MTD has not yet been reached. PT-112’s profile makes it an attractive candidate for further development, including in combination with immunotherapy. Clinical trial information: NCT02266745.

Return to work after general surgery: A comparative study

PURPOSES

There is scarce information on the time to return to work after general surgery. The aim of this study was to analyze time off work after elective cholecystectomy and to compare the results with those in patients undergoing other surgical interventions.

METHODS

Observational and comparative study. Inclusion criteria were: being of working age and undergoing elective laparoscopic cholecystectomy (group 1) or unilateral inguinal hernia or haemorrhoidectomy (group 2).

RESULTS

36 patients were included: 18 patients in each group. Overall, return to work occurred at a mean of 35.7 days, with no significant differences (p=0.656) between groups (group 1: 36.6 days vs. group 2: 35.44 days). The reasons for not returning to work earlier were fear of complications (37.5%), pain control (37.5%), surgeon recommendation (12.5%), and general practitioner recommendation (12.5%).

CONCLUSIONS

Time to recovery after laparoscopic cholecystectomy is prolonged. No statistically significant differences with less complex surgical procedures were detected.

ErbB3 expression predicts sensitivity to elisidepsin treatment: in vitro synergism with cisplatin, paclitaxel and gemcitabine in lung, breast and colon cancer cell lines

Irvalec® (elisidepsin trifluoroacetate, PM02734) is a novel marine-derived cyclic peptide belonging to the Kahaladide family of compounds, currently in clinical trials with preliminary evidence of antitumor activity. Previous studies have shown a correlation between elisidepsin sensitivity and expression of the ErbB3 receptor in a panel of NSCLC cell lines. We have studied the effect of elisidepsin on the ErbB3 pathway, characterizing the expression of all members of the ErbB (HER) family of receptors and their main downstream signaling effectors, such as Akt and MAPK. Interestingly, we observed a downregulation of ErbB3 upon elisidepsin treatment that correlates with a reduction in the Akt phosphorylation levels in the most sensitive cell lines, whereas ErbB3 levels are not affected in the less sensitive ones. Also, we observed that the basal levels of ErbB3 protein expression show a significant correlation with cell viability response against elisidepsin treatment in 14 different cell lines. Furthermore, we analyzed the combination of elisidepsin with different chemotherapeutics agents, such as cisplatin, paclitaxel and gemcitabine, in a panel of different breast (MDA-MB-435, MDA-MB-231 and MCF7), lung (HOP62, DV90 and A549) and colorectal cancer cell lines (DLD1 and HT29). IC50 values for the different drugs were tested. We observed a synergistic effect in all cell lines tested with any chemotherapeutic agent. More importantly, the two in vitro elisidepsin-resistant cell lines (MDA-MB-231 and HOP62) presented a synergistic effect in combination with cisplatin and paclitaxel, respectively. These results provide a rationale for further development of these combinations in an ongoing clinical trial.

ERCC5/XPG, ERCC1, and BRCA1 gene status and clinical benefit of trabectedin in patients with soft tissue sarcoma

BACKGROUND

The objective of this study was to determine whether specific single nucleotide polymorphisms (SNPs) from nucleotide excision repair (NER) and homologous recombination (HR) DNA repair pathways are associated with sensitivity to trabectedin in patients with soft tissue sarcoma (STS).

METHODS

The authors analyzed excision repair cross-complementation group 5/xeroderma pigmentosum group G (ERCC5/XPG) (NER), excision repair cross-complementation group 1 (ERCC1) (NER), and breast cancer 1 (BRCA1) (HR) SNPs and messenger RNA expression levels in tumor specimens from 113 patients with advanced STS who were enrolled in previously published phase 2 trials or in a compassionate-use program. The 6-month progression-free rate (PFR), progression-free survival (PFS), and overall survival (OS) were analyzed according to ERCC5, ERCC1, and BRCA1 status using log-rank tests.

RESULTS

High expression of the common allele (aspartic acid at codon 1104) of ERCC5, high expression of ERCC1, and BRCA1 haplotype were associated significantly with improved PFR, PFS, and OS. The ERCC1 thymine-to-cytosine (T→C) SNP at codon 19007 and BRCA1 expression were not associated with outcome. On univariate analysis, tumor histology, favorable NER status (high expression of common ERCC5 and/or high ERCC1 expression status), and favorable BRCA1 haplotype (at least 1 triple-adenine plus guanine [AAAG] allele) were the sole variables associated significantly with PFS and OS.

CONCLUSIONS

In the current study, ERCC5, ERCC1, and BRCA1 status represented a potential DNA repair signature that could be used for the prediction of clinical response to trabectedin in patients with STS.

Heparin and suramin alter plitidepsin uptake via inhibition of GPCR coupled signaling

Plitidepsin (Aplidin) is a novel antitumor agent, derived from the mediterranean tunicate Aplidium albicans, and is currently in phase ii clinical trials with evidence of activity in heavily pretreated multiple myeloma, renal cell carcinoma, melanoma and neuroblastoma patients. As compared to its parental compound didemnin B, plitidepsin has shown a better therapeutic index with less bone marrow toxicity, cardiotoxicity and neurotoxicity in patients and a more potent cytotoxic effect in several tumor cell lines. As sensitivity to the drug varies between cell lines and fresh leukemia samples, we performed studies on transport of plitidepsin in leukemia and lymphoma cell lines to determine the mechanism of uptake. The drug is taken up by an active transport process, i.e. the process is temperature and energy dependent, and has a high-affinity binding site with Kt =212 nM and Vmax = 15 pmoles/min. Importantly, once inside the cell, efflux of plitidepsin is minimum, suggesting that the drug is bound to intracellular macromolecules. Further work showed that plitidepsin binds to G-Protein Coupled Receptors (GPCRs), since GPCR and GRK (GPCR kinases) inhibitors suramin and heparin respectively, markedly reduce the drug uptake and its cytotoxic activity. Signaling via Jak/Stat pathway is inhibited by pharmacological concentrations of plitidepsin, further confirming the relationship between plitidepsin and GPCRs.

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.

Clinical impact of trabectedin (ecteinascidin-743) in advanced/metastatic soft tissue sarcoma

BACKGROUND

Patients with advanced or metastatic non-gastrointestinal stromal tumour soft tissue sarcoma (STS) whose disease progresses during or after chemotherapy with doxorubicin or ifosfamide have few options and very limited life expectancy. In this setting, the DNA and transcription interacting agent trabectedin (ecteinascidin-743), isolated originally from the tunicate Ecteinascidia turbinata, has encouraging activity and is now approved in the European Union.

OBJECTIVE

To review evidence for the efficacy of trabectedin in STSs.

METHODS

This review includes material known to the authors through preclinical and clinical work with trabectedin, and information from relevant papers and abstracts.

RESULTS

Pooled analysis of Phase II studies suggests that around 50% of STS patients, failing conventional chemotherapy, experienced long lasting tumour control (either objective response or stabilization of disease) when treated with trabectedin. Twenty-nine per cent of patients were alive at 2 years, and median overall survival was 10.3 months. Leiomyosarcomas and liposarcomas appear particularly sensitive to the drug. In myxoid and round-cell liposarcomas trabectedin seems exceptionally active. A link between specific translocations underlying this disease and the drug's mechanism of action is being explored. Trabectedin is also active in synovial, ewing sarcoma and other translocation-related STSs. Trabectedin is not cardio- or neurotoxic. The neutropenia and hepatic toxicity that occur are non-cumulative, reversible, and lessened by steroid premedication. The lack of cumulative toxicities could make trabectedin appropriate for prolonged treatment.

CONCLUSION

The potential of trabectedin should be further explored in STSs in general and in specific subtypes, both in combination with other cytotoxic agents and with modulators of intracellular signalling.

Aplidin synergizes with cytosine arabinoside: functional relevance of mitochondria in Aplidin-induced cytotoxicity

Aplidin (plitidepsin) is a novel marine-derived antitumor agent presently undergoing phase II clinical trials in hematological malignancies and solid tumors. Lack of bone marrow toxicity has encouraged further development of this drug for treatment of leukemia and lymphoma. Multiple signaling pathways have been shown to be involved in Aplidin-induced apoptosis and cell cycle arrest in G1 and G2 phase. However, the exact mechanism(s) of Aplidin action remains to be elucidated. Here we demonstrate that mitochondria-associated or -localized processes are the potential cellular targets of Aplidin. Whole genome gene-expression profiling (GEP) revealed that fatty acid metabolism, sterol biosynthesis and energy metabolism, including the tricarboxylic acid cycle and ATP synthesis are affected by Aplidin treatment. Moreover, mutant MOLT-4, human leukemia cells lacking functional mitochondria, were found to be resistant to Aplidin. Cytosine arabinoside (araC), which also generates oxidative stress but does not affect the ATP pool, showed synergism with Aplidin in our leukemia and lymphoma models in vitro and in vivo. These studies provide new insights into the mechanism of action of Aplidin. The efficacy of the combination of Aplidin and araC is currently being evaluated in clinical phase I/II program for the treatment of patients with relapsed leukemia and high-grade lymphoma.

Sensitivity of myxoid-round cell liposarcoma (MRCL) to trabectedin (T) may be related to a direct effect on the fusion transcript

10000

Background: Myxoid-round cell liposarcomas (MRCL) is a variant of liposarcoma, associated with t(12;16)(q13;p11) and the rarer t(12;22)(q13;q12) chromosomal translocation, resulting in the FUS-CHOP and EWS-CHOP fusion proteins, supposed to act as aberrant transcription factors. We reported the exceedingly high clinical efficacy of T against MRCL, which is a magnitude higher in comparison to other liposarcomas and sarcomas. Reasons thereof remain unknown, but a distinct mechanism of action of T in MRCL is suspected on clinical grounds. Methods: Tumor biopsies were taken from 9 MRCL patients (pts) before starting T, and the tumor was fully characterized by cytogenetic and molecular analysis. Primary cultures were set up, and tumor fragments were transplanted in scid mice, to develop an experimental model aimed at investigating the mechanism of action of T. Chromatin immunoprecipitation (ChIP) analysis on the 402–91 myxoid liposarcoma cell line was performed, to characterize the DNA binding capability of FUS-CHOP. Finally, in vivo ChIP analyses are currently ongoing, using tumor samples obtained before and after therapy with T. Tumor samples from 3 patients have been processed so far. Results: All patients had t(12–16) by FISH. Molecular characterization showed that 7 pts had the type II transcript, 1 had the type III, and 1 both type II and III. Primary cultures evaluated after the first 3 passages were morphologically, cytogenetically and molecularly consistent with the original tumor, as well as the 4 tumours grown in mice so far. In the myxoid liposarcoma cell line carrying the type I transcript, selective binding of FUS-CHOP to some promoters was seen. Impairment of this binding activity was observed after treatment with T at concentration 1–4 nM. Conclusions: There is in vitro evidence of a direct effect of T on the fusion protein's ability to bind to promoters. In vivo studies on the experimental model are ongoing, and results will be presented.

No significant financial relationships to disclose.

Trabectedin (T) in metastatic Ewing's family tumors (EFT) patients (pts) progressing after standard chemotherapy

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Background: T is a formerly marine-derived agent which is active in human cancers, such as ovarian cancer and adult soft tissue sarcomas (STS). Efficacy of T in pts with unresectable/metastatic pretreated advanced STS was demonstrated in phase II settings. Leiomyosarcoma and liposarcoma were shown to be sensitive, with myxoid liposarcoma being exceedingly responsive. Data are lacking on “small round blue cell” sarcomas, including EFT. In 2000 a phase II study was launched by SENDO in a sarcoma population including EFT. At Istituto Nazionale Tumori, Milano, Italy, some EFT pts were treated after the completion of this study. We analyzed treatment efficacy in EFT pts treated within these two settings. Methods: Overall 15/29 of the pts were female, and age ranged from 15 to 55 years. Pts received T at a starting dose between 1,650 and 1,100 mcg/sqm every 3 weeks as 24-hour or 3-hour infusion. Each pt received at least 2 cycles of treatment, except in case of disease progression or unacceptable toxicity. Tumor response was assessed by RECIST criteria after the first 2 cycles and then every other cycle. Dose reductions were based on the worst toxicity (hematological or non-hematological) in the previous cycle. Results: As of December 2006, 20 pts were treated in the Phase II study, and 9 on a compassionate use basis. Two pts were still on therapy. A total of 79 treatment cycles (2–14 per pt) were administered. Three pts (10.3%) demonstrated a partial response, 3 had a minor response (10.3%), and 4 (13.7%) stable disease. PFS rate at 6 months was 25%. The most common all-causality AEs were acute reversible liver toxicity, fatigue, and myelosuppression. Following the introduction of steroid pre-medication, thrombocytopenia and fatigue were less frequent. Conclusions: In this cohort, T was overall well tolerated and showed antitumor activity in pts with advanced EFT. This calls for further evaluation of this compound, alone or in combination, in pts suffering from EFT.

No significant financial relationships to disclose.

Extreme sensitivity to Yondelis (Trabectedin, ET-743) in low passaged sarcoma cell lines correlates with mutated p53

Yondelis (Trabectedin, ET-743) is a marine anticancer agent currently in Phase II/III development in patients with advanced pretreated soft tissue sarcoma. In the present study, we generated a panel of low passaged tumor cell lines from samples explanted from chemonaive sarcoma patients with different tumor types. We assessed in vitro sensitivity/resistance to Trabectedin and doxorubicin in a panel of sarcoma cell lines and examined the correlation between molecular alterations in DNA repair genes and sensitivity to Trabectedin. We treated cell lines with Trabectedin and doxorubicin in both 96-h and clonogenic assays. In both assays, well-defined groups of resistant and sensitive cell lines were observed. Resistance to Trabectedin did not correlate with resistance to doxorubicin, indicating that the two drugs may have different mechanisms of resistance. p53 mutations and deletions correlated with extreme sensitivity (IC50 < 1 nM) to Trabectedin (P < 0.01). In a pair of isogenic cell lines differing only in the presence or absence of wild-type p53, the absence of p53 rendered cells threefold more sensitive to Trabectedin.

Phase I study of Aplidine in a dailyx5 one-hour infusion every 3 weeks in patients with solid tumors refractory to standard therapy. A National Cancer Institute of Canada Clinical Trials Group study: NCIC CTG IND 115

BACKGROUND

Aplidine is a cyclic depsipeptide isolated from the marine tunicate Aplidium albicans.

METHODS

This phase I study of Aplidine given as a 1-hour i.v. infusion daily for 5 days every 3 weeks was conducted in patients with refractory solid tumors. Objectives were to define the dose limiting toxicities, the maximal tolerated dose, and the recommended phase II dose.

RESULTS

Thirty-seven patients were accrued on study. Doses ranged from 80 microg/m(2) to 1500 microg/m(2)/day. Eleven patients received more than three cycles of Aplidine. Dose-limiting toxicities occurred at 1500 microg/m(2) and 1350 microg/m(2)/day and consisted of nausea, vomiting, myalgia, fatigue, skin rash and diarrhea. Mild to moderate muscular pain and weakness was noted in patients treated with multiple cycles with no significant drug related neurotoxicity. Bone marrow toxicity was not observed. The recommended dose for phase II studies was 1200 microg/m(2) daily for 5 days, every 3 weeks. Pharmacokinetic studies performed during the first cycle demonstrated that therapeutic plasma levels of Aplidine are reachable well below the recommended dose. Nine patients with progressive disease at study entry had stable disease and two had minor responses, one in non-small cell lung cancer and one in colorectal cancer.

CONCLUSIONS

Aplidine given at a dose of 1200 microg/m(2) daily for 5 days, every 3 weeks is well tolerated with few severe adverse events. This schedule of Aplidine is under evaluation in phase II studies in hematological malignancies and solid tumors.

A phase II study of Yondelis (trabectedin, ET-743) as a 24-h continuous intravenous infusion in pretreated advanced breast cancer

Yondelis® (trabectedin, ET-743) is a novel marine-derived anticancer compound found in the ascidian Ecteinascidia turbinata. It is currently under phase II/III development in breast cancer, hormone refractory prostate cancer, sarcomas and ovarian cancer. Activity in breast cancer experimental models has been reported, and preliminary evidence of activity in this setting during the phase I programme has also been observed. The present study assessed the activity and feasibility of trabectedin in women with advanced breast cancer previously treated with conventional therapies. Patients with advanced disease previously treated with at least one but not more than two regimens that included taxanes or anthracyclines as palliative therapy were eligible. Trabectedin 1.5 mg m⁻² was administered as a 24-h continuous infusion every 3 weeks. Patients were kept on therapy until disease progression, unacceptable toxicity or patient refusal. Twenty-seven patients were included between April 1999 and September 2000. Their median age was 54 years (range: 36–67) and 63% of them had two metastatic sites. Twenty-two patients were performance status 1. All patients had previously received anthracyclines, and 23 out of 27 patients had received taxanes. Of 21 patients with measurable disease, three confirmed partial responses, one unconfirmed partial response and two minor responses (49 and 32% tumour shrinkage) were observed; six patients had stable disease. Median survival was 10 months (95% confidence interval: 4.88–15.18). Transient and noncumulative transaminitis was observed in most of the patients. The pharmacokinetic profile of trabectedin in this patient's population is in line with the overall data available with this schedule. The policy of dose adjustments based on the intercycle peaks of bilirubin and alkaline phosphatase appears to have a positive impact in the therapeutic index of trabectedin. Trabectedin can induce response and tumour control in previously treated advanced breast cancer, with manageable toxicity, thus warranting further development as a single agent or in combination regimens.

Steroid premedication markedly reduces liver and bone marrow toxicity of trabectedin in advanced sarcoma

Trabectedin is a marine-derived cytoxic alkaloid which has shown promising antitumour activity in a variety of human malignancies including sarcoma. Fifty-four patients with advanced sarcoma (age 43 yrs, range 18-70), all pretreated with prior chemotherapy, were enrolled on a named individual basis for treatment with trabectedin. Diagnosis was adult soft tissue sarcoma (STS) in 46 patients, Ewing's family tumour (EFT) in 4, and osteosarcoma (OS) in 4. The initial 23 patients (total number of courses administered: 68) did not receive premedication prior to trabectedin, while the other 31 patients (total number of courses administered: 134) received premedication with dexamethasone 4 mg po bid 24 hours before therapy. Incidence of toxicity (grade 3-4), expressed as percentage of courses, was as follows: in patients without dexamethasone, elevation of transaminases 34%, neutropenia 24% and thrombocytopenia 25%; in patients with prior dexamethasone, elevation of transaminases 2%, neutropenia 2% and no thrombocytopenia. The median received dose intensity of trabectedin was superimposable in the two groups (404 microg and 400 microg per week, respectively), as well as progression-free survival (19% at 6 months). Among STS patients, 9% had objective responses. In this unselected patient series, premedication with dexamethasone strongly reduced drug-induced hepatotoxicity and myelosuppression.

Patterns of tumor response to trabectedin (ET743) in myxoid liposarcomas

9511

Background: Trabectedin (T) is a marine-derived agent found to be active in ovarian cancer and sarcomas. Among sarcomas, activity has been notable in leiomyosarcomas and liposarcomas. Since liposarcomas are a heterogeneous group, including well/de-differentiated, pleomorphic, and myxoid/round cell subtypes, we have noted particularly interesting patterns of responsiveness to T in myxoid liposarcomas, which are associated with t(12;16)(q13;p11) or t(12;22)(q13;q12) chromosomal translocations, resulting in CHOP-TLS or CHOP-EWS fusion products. Methods: 15 cases of myxoid liposarcomas treated with T at the Istituto Nazionale Tumori, Milan, were retrospectively reviewed. In most cases, T was given as a 24-hr continuous infusion every 21 days, at dose levels from 1.0 to 1.5 mg/sqm. 108 courses were delivered, with a median of 5 courses per patient (range 2–20). Observations made in this series were shared with five other institutions having treated myxoid liposarcoma cases with T, all of which also report a significant response rate, for a total of 44 pts. A centralized radiological review of all pts is ongoing. Results: In the Milan series, early tissue alterations in tumors were observed in 14 patients, mainly with a decrease in tumor density on CT scan and/or decrease in contrast enhancement on MRI. These changes were followed by tumor shrinkage amounting to a conventional PR/CR in 8 (pending final review), while 3 others have responses which continue to evolve. Progression followed treatment interruption in one patient, with a minor response occurring at treatment restart. Treatment is continuing in 12 pts (median duration of therapy in excess of 5 months). Further results of the central radiological review from all centres will be reported. Conclusions: Tumor response to T seen in myxoid liposarcoma appears to be marked by early radiological alterations in tumor tissue, often preceding tumor shrinkage, which may be delayed. A selective mechanism of action for this chromosomal translocation-related sarcoma is suggested, and is being actively investigated at the moment.

[Table: see text]

Ecteinascidin-743 (ET-743) for chemotherapy-naive patients with advanced soft tissue sarcomas: multicenter phase II and pharmacokinetic study

PURPOSE

To evaluate the response rate, toxicity profile, and pharmacokinetics of ecteinascidin-743 (ET-743) as first-line therapy in patients with unresectable advanced soft tissue sarcoma (STS).

PATIENTS AND METHODS

Thirty-six patients with STS were enrolled onto the study between September 1999 and August 2000. Patients were treated with 1.5 mg/m2 of ET-743 given as a 24-hour continuous intravenous (IV) infusion every 21 days. Pharmacokinetic sampling was performed in 23 patients.

RESULTS

One complete and five partial responses were achieved in 35 assessable patients for an overall response rate of 17.1% (95% CI, 6.6% to 33.6%). In addition, one patient had a minor response, leading to an overall clinical benefit of 20%. Neutropenia and transaminitis were the main grade 3 to 4 toxicities, which occurred in 33% and 36% of the patients. The estimated 1-year progression-free and overall survival rates were 21% (95% CI, 11% to 41%) and 72% (95% CI, 59% to 88%), respectively. Total body clearance (L/h) was not significantly correlated with body-surface area (r = -0.28; P = .21). Mild hepatic impairment or the extent of prior cytotoxic therapy does not seem to contribute significantly to the high interpatient variability (49%) in the clearance of this drug. Severity of treatment-related toxicity was not correlated with pharmacokinetic variables.

CONCLUSION

ET-743 demonstrates clinical activity as first-line therapy against STS with acceptable toxicity. Additional studies to establish empirical dosing guidelines may be necessary to improve the safety of the drug in patients with varying degrees of hepatic dysfunction and definitively establish the role of ET-743 for patients with these malignancies.

VEGF inhibition and cytotoxic effect of aplidin in leukemia cell lines and cells from acute myeloid leukemia

BACKGROUND

Aplidine (APL) is a marine depsipeptide isolated from the Mediterranean tunicate Aplidium albicans that is under clinical phase II development. In contrast to the lack of bone marrow toxicity reported in phase I/II studies, it has been shown to induce cytotoxicity at very low concentration against lymphoblastic leukemia blast, as well as having an impact in the vascular endothelial growth factor (VEGF)/VEGF receptor 1 loop.

PATIENTS AND METHODS

To confirm these findings we investigated APL-related VEGF inhibition and its cytotoxic effect on myeloid leukemic cells lines (K-562, HEL and HL60) and fresh leukemia blasts derived from 30 patients with acute myeloid leukemia (AML). The conventional active 4-demetoxi-daunorubicin (idarubicin; IDA) was included as a positive control.

RESULTS

APL was found to be significantly (P<0.001) more active than IDA in obtaining 50% growth-inhibition in K-562, HEL and HL60 cell lines. Results obtained with AML blast cells were super imposible. ID(50) ranged from 0.024 to 0.610 microM for IDA (0.200+/-0.176) and from 0.001 to 0.108 microM for APL (0.020+/-0.031). Annexin V tests and cell cycle analysis performed on cell lines confirmed the stronger citotoxic capability of APL as apoptotic inducer and as a G(1) blocker. The inhibitory effects of APL on VEGF release and secretion have been confirmed by ELISA tests performed on HEL: the VEGF concentration in cell surnatant was reduced from 169 to 36 pg/ml after 24 h of exposure to a pharmacological concentration of APL.

CONCLUSIONS

APL harbors a strong in vitro antileukemic activity at a concentration achievable in patients at non-myelotoxic doses. Our data also support the notion of an impact on VEGF secretion. Clinical studies with this new marine-derived compound in relapsed/resistant leukemia are underway.

Aplidin reduces growth of anaplastic thyroid cancer xenografts and the expression of several angiogenic genes

BACKGROUND

Anaplastic thyroid cancer (ATC) is one of the most aggressive and highly lethal human cancers. Median survival after diagnosis is 4-6 months despite available radiotherapy and chemotherapy. Additional treatments are needed for ATC. Vascular endothelial growth factor (VEGF) is a potent angiogenic stimulus, which is expressed by ATC. Previously, anti-VEGF antibody was used to block VEGF-dependent angiogenesis in ATC xenografts. This treatment induced partial (56%) but not complete tumor regression. Aplidin (APLD) is a marine derived antitumor agent currently in phase II clinical studies. Multiple activities of this compound have been described which likely contribute to its antiproliferative effect. Notably, APLD has been shown to have antiangiogenic properties which include: inhibition of VEGF secretion, reduction in the synthesis of the VEGF receptor (FLT-1), and blockade of matrix metalloproteinase production by endothelial cells. We hypothesized that Aplidin, with its broad spectrum of action and antiangiogenic properties, would be a potentially effective drug against ATC.

METHODS

Thirty BALB/c nu/nu mice were injected with ATC cells (ARO-81, 1 x 10(6)) and allowed to implant for 3 weeks. Animals were randomized to receive daily intraperitoneal injections of vehicle, low dose (0.5 mg/kg/day), or high dose (1.0 mg/kg/day) APLD. After 3 days, the animals were killed and the tumors were removed, weighed, and divided for RNA and protein analyses.

RESULTS

APLD significantly reduced ATC xenograft growth (low dose, 20% reduction, P = 0.01; high dose, 40% reduction, P < 0.001). This was associated with increased levels of apoptosis related proteins polyadenosylribose polymerase 85 (PARP-85, 75% increase, P = 0.024) and caspase 8 (greater than fivefold increase, P = 0.03). APLD treatment was further associated with lost or reduced expression of several genes that support angiogenesis to include: VEGF, hypoxia inducible factor 1(HIF-1), transforming growth factor-beta (TGFbeta), TGFbeta receptor 2 (TGFbetaR2), melanoma growth stimulating factor 1 (GRO1), cadherin, and vasostatin.

CONCLUSIONS

This data supports the hypothesis that APLD may be an effective adjunctive therapy against ATC. The demonstrated molecular impact against angiogenic related genes specifically supports future strategies combining APLD with VEGF interacting agents.

Phase II study of ET-743 in advanced soft tissue sarcomas: a European Organisation for the Research and Treatment of Cancer (EORTC) soft tissue and bone sarcoma group trial

PURPOSE

This nonrandomized multicenter phase II study was performed to evaluate the activity and safety of Ecteinascidin (ET-743) administered at a dose of 1.5 mg/m(2) as a 24-hour continuous infusion every 3 weeks in patients with pretreated advanced soft tissue sarcoma.

PATIENTS AND METHODS

Patients with documented progressive advanced soft tissue sarcoma received ET-743 as second- or third-line chemotherapy. Antitumor activity was evaluated every 6 weeks until progression, excessive toxicity, or patient refusal.

RESULTS

One hundred four patients from eight European institutions were included in the study (March 1999 to November 2000). A total of 410 cycles were administered in 99 assessable patients. Toxicity mainly involved reversible grade 3 to 4 asymptomatic elevation of transaminases in 40% of patients, and grade 3 to 4 neutropenia was observed in 52% of patients. There were eight partial responses (PR; objective regression rate, 8%), 45 no change (NC; > 6 months in 26% of patients), and 39 progressive disease. A progression arrest rate (PR + NC) of 56% was observed in leiomyosarcoma and 61% in synovialosarcoma. The median duration of the time to progression was 105 days, and the 6-month progression-free survival was 29%. The median duration of survival was 9.2 months.

CONCLUSION

ET-743 seems to be a promising active agent in advanced soft tissue sarcoma, with no cumulative toxicities. The 6-months progression-free survival observed in advanced soft tissue sarcoma compares favorably with those obtained with other active drugs tested in second-line chemotherapy in previous European Organisation for the Research and Treatment of Cancer trials. The median overall survival was unusually long in these heavily pretreated patients mainly due to the high number of patients who benefit from the drug in terms of tumor control.

A phase I and pharmacokinetic study of ecteinascidin-743 (Yondelis) in children with refractory solid tumors. A Children's Oncology Group study

PURPOSE

To determine the dose-limiting toxicity (DLT) and the maximum tolerated dose of ecteinascidin-743 (ET-743, Yondelis) in children with refractory solid tumors, to establish the recommended dose for pediatric phase II trials, and to characterize the pharmacokinetics of ET-743 in children.

EXPERIMENTAL DESIGN

ET-743 was administered as a 3-hour i.v. infusion every 21 days. The starting dose was 1,100 microg/m(2) with planned dose escalation of 200 microg/m(2) increments. Pharmacokinetic sampling was done during the first treatment course.

RESULTS

Twelve evaluable patients received a total of 29 courses. One grade 4 DLT (prolonged grade 4 neutropenia) was noted at the first dose level. At the second dose level (1,300 microg/m(2)), there were two DLTs (reversible grade 4 elevations of hepatic transaminase); hence the maximum tolerated dose was defined as 1,100 microg/m(2). Overall, reversible hepatic toxicity, manifested as grade 3 or 4 elevations in hepatic transaminase, occurred in more than 50% of the patients. No grade 3 or 4 thrombocytopenia was reported at either dose level and only one episode of isolated creatine phosphokinase grade 4 elevation was observed. One complete response was documented after six courses in a patient with metastatic Ewing sarcoma. The pharmacokinetics of ET-743 in 8 children was characterized by a terminal disposition phase with a mean half-life of 43.8 +/- 18.4 hours, a total body clearance of 28.2 +/- 10.5 L/h/m(2), and a 959 +/- 807 L/m(2) steady-state apparent volume of distribution.

CONCLUSION

ET-743 is safe. The phase II recommended dose of ET-743 administered as a 3-hour i.v. infusion following premedication with dexamethasone is 1,100 microg/m(2).

A Phase I and Pharmacokinetic Study of Ecteinascidin-743 (Yondelis) in Children with Refractory Solid Tumors. A Children's Oncology Group Study

Purpose: To determine the dose-limiting toxicity (DLT) and the maximum tolerated dose of ecteinascidin-743 (ET-743, Yondelis) in children with refractory solid tumors, to establish the recommended dose for pediatric phase II trials, and to characterize the pharmacokinetics of ET-743 in children.

Experimental Design: ET-743 was administered as a 3-hour i.v. infusion every 21 days. The starting dose was 1,100 μg/m2 with planned dose escalation of 200 μg/m2 increments. Pharmacokinetic sampling was done during the first treatment course.

Results: Twelve evaluable patients received a total of 29 courses. One grade 4 DLT (prolonged grade 4 neutropenia) was noted at the first dose level. At the second dose level (1,300 μg/m2), there were two DLTs (reversible grade 4 elevations of hepatic transaminase); hence the maximum tolerated dose was defined as 1,100 μg/m2. Overall, reversible hepatic toxicity, manifested as grade 3 or 4 elevations in hepatic transaminase, occurred in more than 50% of the patients. No grade 3 or 4 thrombocytopenia was reported at either dose level and only one episode of isolated creatine phosphokinase grade 4 elevation was observed. One complete response was documented after six courses in a patient with metastatic Ewing sarcoma. The pharmacokinetics of ET-743 in 8 children was characterized by a terminal disposition phase with a mean half-life of 43.8 ± 18.4 hours, a total body clearance of 28.2 ± 10.5 L/h/m2, and a 959 ± 807 L/m2 steady-state apparent volume of distribution.

Conclusion: ET-743 is safe. The phase II recommended dose of ET-743 administered as a 3-hour i.v. infusion following premedication with dexamethasone is 1,100 μg/m2.

A phase II study of ET-743/trabectedin (`Yondelis') for patients with advanced gastrointestinal stromal tumours

Primary or secondary resistance to imatinib may occur in patients with gastrointestinal stromal tumours (GISTs) while these tumours have repeatedly been shown to be highly resistant to conventional doxorubicin- and ifosfamide-containing regimens. The investigation of new drugs is therefore warranted in GIST. A phase II study was conducted between May 1999 and November 2000 in eight centres of the EORTC STBSG group to establish the efficacy and safety of ET743 ('Yondelis') in GIST previously untreated with cytotoxic chemotherapy before the imatinib era. ET-743 was given was given at 1.5 mg/m(2) per course as a 24-h continuous intravenous infusion every 3 weeks. Twenty-eight patients were included, 16 males and 12 females. Median age was 54 years (range 25-73 years). Median performance status was 0 (range 0-1). 17 (63%), 4 (12%) and 7 (25%) patients, received 0-2, 3-5, and > or = 6 courses of ET-743, respectively. The best response was stable disease in 9 (33%) patients, and disease progression in 18 patients (67%), with a median time to disease progression and overall survival of 51 days and 589 days, respectively. The treatment was well tolerated: there were grades 3-4 neutropenia, thrombocytopenia, and transaminase increases in 13 (48%), 1 (4%) and 16 (59%) patients, respectively. There were no toxic deaths. ET-743 at this dose and schedule is not an effective treatment for advanced GIST.

Phase II and pharmacokinetic study of ecteinascidin 743 in patients with progressive sarcomas of soft tissues refractory to chemotherapy

PURPOSE

To assess the efficacy of the marine-derived alkaloid ecteinascidin 743 (ET-743) in patients with soft tissue sarcomas that progressed despite prior conventional chemotherapy and to characterize the pharmacokinetic profiles of ET-743 in this patient population.

PATIENTS AND METHODS

Thirty-six previously treated soft tissue sarcoma patients from three institutions received ET-743 as a 24-hour continuous intravenous (IV) infusion at a dose of 1,500 microg/m(2) every 3 weeks. Pharmacokinetic studies were also performed. Patients were restaged every two cycles for response by objective criteria.

RESULTS

Objective responses were observed in three patients, with one complete response and two partial responses, for an overall response rate of 8% (95% CI, 2% to 23%). Responses were durable for up to 20 months. Two minor responses (43% and 47% tumor reduction) were observed, for an overall clinical benefit rate of 14%. The predominant toxicities were neutropenia and self-limited transaminitis of grade 3 to 4 severity in 34% and 26% of patients, respectively. The estimated 1-year time to progression and overall survival rates were 9% (95% CI, 3% to 27%) and 53% (95% CI, 39% to 73%), respectively. The maximum observed plasma concentration and total plasma clearance of ET-743 (mean +/- standard deviation), 1.04 +/- 0.48 ng/mL and 35.6 +/- 16.2 L/h/m(2), respectively, were consistent with previously reported values from phase I studies of the drug given as a 24-hour IV infusion.

CONCLUSION

ET-743 is a promising new option for the management of several histologic subtypes of sarcoma. Durable objective responses were obtained in a subset of sarcoma patients with disease progression despite prior chemotherapy. Additionally, the relatively high survival rate noted in this series of previously treated patients further justifies development of this agent.

Progress in the clinical development of new marine-derived anticancer compounds

Naturally derived anticancer agents continue to be instrumental in the systemic therapeutic intervention against solid tumors and hematological malignancies. Such compounds now have a relevant role in contemporary models of combination with targeted agents, thus providing a rationale to consider nature as a valid tool to discover new innovative anticancer agents. The marine ecosystem has increasingly been the focus of interest for new discoveries in the field that are expected to be of significant therapeutic impact in cancer patients. A critical review of the integrated data generated in our marine-derived anticancer program seems to confirm such expentancies. ET-743 (Yondelis) represents the first new agent developed against advanced pretreated soft tissue sarcoma in the past 25 years, and also harbors activity in women bearing pretreated ovarian cancer and a solid potential in combination therapy. The lack of cumulative toxicities makes this compound suitable for long-lasting therapies, reversible transaminitis being the most prevalent toxicity. Aplidin has shown a positive therapeutic index in phase I trials and phase II studies are ongoing. In contrast to the lack of bone marrow toxicity, a set of translational results anticipates a potential in leukemia. Kahalalide F has also successfully completed the phase I program in solid tumors with evidence of activity in resistant tumors and phase II studies are under way. Finally, the mechanistic data generated in parallel with the clinical program confirms the potential of the marine ecosystem in the discovery of new agents acting against new cellular targets of relevance in cancer cell biology.

Phase II study of ecteinascidin-743 in advanced pretreated soft tissue sarcoma patients

PURPOSE

A multicenter phase II study evaluating efficacy, safety, and pharmacokinetics of ecteinascidin-743 (ET-743) in pretreated advanced soft tissue sarcoma patients.

PATIENTS AND METHODS

Patients received ET-743 1,500 microg/m(2) (24-hour intravenous infusion) every 3 weeks (group 1, 26 patients with one to two prior single agents or one previous combination chemotherapy; group 2, 28 patients with three or more prior single agents or two or more previous combination chemotherapies). Results Patients (30 women, 24 men) had a median age of 48 years (range, 22 to 71 years); 41% had leiomyosarcoma (eight of 22 of uterine origin), a median of two involved organs (range, one to four), and 93% had documented progressive disease at study entry. Patients received a median of three cycles (range, one to 20); 28% received six or more cycles. Fifty-two patients were assessable for response (WHO criteria): two partial responses, four minor responses, and nine with stable disease (> or = 6 months). Three patients were rendered tumor free after surgery. Median progression-free survival was 1.9 months (range, 0.69 to 17.90 months); 24% of patients were progression free at 6 months. Median survival was 12.8 months, with 30% of patients alive at 2 years. Four patients withdrew because of treatment-related toxicity. Two treatment-related deaths occurred (renal failure and febrile neutropenia, and rhabdomyolysis and decompensated cirrhosis, respectively) that were probably related to protocol eligibility violations. Reversible grade 3 to 4 AST or ALT occurred in 50% of patients and grade 3 to 4 neutropenia occurred in 61% of patients, with six episodes of febrile neutropenia. Nausea, vomiting, and asthenia were prevalent but mild and manageable.

CONCLUSION

With a 4% overall response rate (95% CI, 0.5 to 12.8) and an 11% rate of third-party-verified tumor regression (overall response rate + minor response), ET-743 has a 24% 6-month disease progression control rate, confirming evidence of antitumoral activity and a manageable safety profile in patients experiencing disease progression with pretreated soft tissue sarcoma.

Dietary agent indole-3-carbinol protects female rats against the hepatotoxicity of the antitumor drug ET-743 (trabectidin) without compromising efficacy in a rat mammary carcinoma

ET-743, an experimental antitumor drug with promising activity in sarcoma, breast and ovarian carcinoma, is currently under phase 2 clinical evaluation. It is hepatotoxic in animals and patients. We tested the hypothesis that indole-3-carbinol (I3C), the hydrolysis product of glucosinolates occurring in cruciferous vegetables, may protect against ET-743-induced hepatotoxicity in the female Wistar rat, the animal species with the highest sensitivity toward the adverse hepatic effect of this drug. Hepatotoxicity was adjudged by measurement of plasma levels of bilirubin, alkaline phosphatase (ALP) and aspartate aminotransferase (AST) and by liver histopathology. The effect of I3C on the kinetics of ET-743 in rat plasma and liver was investigated by high-pressure liquid chromatography. The effect of I3C on the antitumor efficacy of ET-743 was explored in rats bearing the 13762 mammary carcinoma. ET-743 (40 microg/kg i.v.) alone caused an elevation of plasma bilirubin, ALP and AST levels and degeneration and patchy focal necrosis of bile duct epithelial cells. Addition of I3C to the diet (0.5%) for 6 days prior to ET-743 administration almost completely abolished manifestations of hepatotoxicity. In contrast, a dietary concentration of 0.1% I3C did not protect, nor did dietary diindolylmethane (0.2%), an acid-catalyzed condensation product of I3C. Ingestion by rats of I3C for 6 days prior to ET-743 (40 microg/kg i.v.) decreased plasma but not hepatic concentrations of ET-743 compared to animals that received ET-743 alone. I3C did not interfere with the antitumor efficacy of ET-743. The results suggest that ingestion of I3C may counteract the unwanted effect of ET-743 in the liver. I3C should be investigated as a hepatoprotectant in patients who receive ET-743 therapy.

Comparison of four modulators of drug metabolism as protectants against the hepatotoxicity of the novel antitumor drug yondelis (ET-743) in the female rat and in hepatocytes in vitro

PURPOSE

Yondelis (ET-743), a tetrahydroisoquinoline alkaloid isolated from a marine tunicate, is a novel drug with demonstrated anticancer activity in early clinical trials against sarcoma, breast and ovarian carcinoma. Yondelis has myelotoxic and hepatotoxic side effects, the latter reflected by reversible transaminitis and cholangitis. In the female rat pretreatment with high-dose dexamethasone has been shown to abrogate yondelis-mediated hepatotoxicity, an effect tentatively linked to its ability to induce cytochrome P450 CYP3A isoenzymes, which metabolize yondelis. Here we tested the hypothesis that pretreatment of rats with modulators of hepatic drug metabolism, beta-naphthoflavone, phenobarbitone or N-acetylcysteine, protect rat livers against the effects of yondelis.

METHODS

Female rats received yondelis (40 microg/kg intravenously) and liver damage in vivo was assessed in terms of changes in plasma levels of bilirubin, alkaline phosphatase (ALP) and aspartate aminotransferase (AST) and by histopathology. In order to investigate yondelis toxicity in vitro, hepatocytes isolated from untreated rats or from rats pretreated with dexamethasone, beta-naphthoflavone or phenobarbitone were maintained in culture and exposed to yondelis.

RESULTS

Pretreatment with beta-naphthoflavone and phenobarbitone ameliorated yondelis-mediated hepatotoxicity in vivo. The former abrogated plasma indicators on day 3, but hardly on day 6, and the latter suppressed elevation of bilirubin, but not of ALP or AST. Pretreatment with N-acetylcysteine did not protect from, but slightly exacerbated, yondelis-induced liver changes. Hepatocytes from naive animals or from pretreated rats did not differ in their susceptibility towards yondelis-induced cytotoxicity in vitro. Nor did inclusion of N-acetylcysteine (1 m M) in the cellular incubation medium affect yondelis-induced hepatocytotoxicity.

CONCLUSIONS

The results suggest that certain inducers of cytochrome P450 enzymes such as dexamethasone and beta-naphthoflavone can protect rat liver against the unwanted effects of yondelis, but such protection cannot be mimicked in in vitro experiments using liver cells in culture.