Arthur P. Staddon

Pazopanib for metastatic soft-tissue sarcoma (PALETTE): a randomised, double-blind, placebo-controlled phase 3 trial.

BACKGROUND Pazopanib, a multitargeted tyrosine kinase inhibitor, has single-agent activity in patients with advanced non-adipocytic soft-tissue sarcoma. We investigated the effect of pazopanib on progression-free survival in patients with metastatic non-adipocytic soft-tissue sarcoma after failure of standard chemotherapy. METHODS This phase 3 study was done in 72 institutions, across 13 countries. Patients with angiogenesis inhibitor-naive, metastatic soft-tissue sarcoma, progressing despite previous standard chemotherapy, were randomly assigned by an interactive voice randomisation system in a 2:1 ratio in permuted blocks (with block sizes of six) to receive either pazopanib 800 mg once daily or placebo, with no subsequent cross-over. Patients, investigators who gave the treatment, those assessing outcomes, and those who did the analysis were masked to the allocation. The primary endpoint was progression-free survival. Efficacy analysis was by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00753688. FINDINGS 372 patients were registered and 369 were randomly assigned to receive pazopanib (n=246) or placebo (n=123). Median progression-free survival was 4·6 months (95% CI 3·7-4·8) for pazopanib compared with 1·6 months (0·9-1·8) for placebo (hazard ratio [HR] 0·31, 95% CI 0·24-0·40; p<0·0001). Overall survival was 12·5 months (10·6-14·8) with pazopanib versus 10·7 months (8·7-12·8) with placebo (HR 0·86, 0·67-1·11; p=0·25). The most common adverse events were fatigue (60 in the placebo group [49%] vs 155 in the pazopanib group [65%]), diarrhoea (20 [16%] vs 138 [58%]), nausea (34 [28%] vs 129 [54%]), weight loss (25 [20%] vs 115 [48%]), and hypertension (8 [7%] vs 99 [41%]). The median relative dose intensity was 100% for placebo and 96% for pazopanib. INTERPRETATION Pazopanib is a new treatment option for patients with metastatic non-adipocytic soft-tissue sarcoma after previous chemotherapy. FUNDING GlaxoSmithKline.

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

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

Phase II Study of the Mammalian Target of Rapamycin Inhibitor Ridaforolimus in Patients With Advanced Bone and Soft Tissue Sarcomas

PURPOSE Ridaforolimus is an inhibitor of mammalian target of rapamycin, an integral component of the phosphatidyl 3-kinase/AKT signaling pathway, with early evidence of activity in sarcomas. This multicenter, open-label, single-arm, phase II trial was conducted to assess the antitumor activity of ridaforolimus in patients with distinct subtypes of advanced sarcomas. PATIENTS AND METHODS Patients with metastatic or unresectable soft tissue or bone sarcomas received ridaforolimus 12.5 mg administered as a 30-minute intravenous infusion once daily for 5 days every 2 weeks. The primary end point was clinical benefit response (CBR) rate (complete response or partial response [PR] or stable disease ≥ 16 weeks). Safety, progression-free survival (PFS), overall survival (OS), time to progression, and duration of response were also evaluated. RESULTS A total of 212 patients were treated in four separate histologic cohorts. In this heavily pretreated population, 61 patients (28.8%) achieved CBR. Median PFS was 15.3 weeks; median OS was 40 weeks. Response Evaluation Criteria in Solid Tumors (RECIST) confirmed response rate was 1.9%, with four patients achieving confirmed PR (two with osteosarcoma, one with spindle cell sarcoma, and one with malignant fibrous histiocytoma). Archival tumor protein markers analyzed were not correlated with CBR. Related adverse events were generally mild or moderate and consisted primarily of stomatitis, mucosal inflammation, mouth ulceration, rash, and fatigue. CONCLUSION Single-agent ridaforolimus in patients with advanced and pretreated sarcomas led to PFS results that compare favorably with historical metrics. A phase III trial based on these data will further define ridaforolimus activity in sarcomas.

Results of an International Randomized Phase III Trial of the Mammalian Target of Rapamycin Inhibitor Ridaforolimus Versus Placebo to Control Metastatic Sarcomas in Patients After Benefit From Prior Chemotherapy

PURPOSE Aberrant mammalian target of rapamycin (mTOR) signaling is common in sarcomas and other malignancies. Drug resistance and toxicities often limit benefits of systemic chemotherapy used to treat metastatic sarcomas. This large randomized placebo-controlled phase III trial evaluated the mTOR inhibitor ridaforolimus to assess maintenance of disease control in advanced sarcomas. PATIENTS AND METHODS Patients with metastatic soft tissue or bone sarcomas who achieved objective response or stable disease with prior chemotherapy were randomly assigned to receive ridaforolimus 40 mg or placebo once per day for 5 days every week. Primary end point was progression-free survival (PFS); secondary end points included overall survival (OS), best target lesion response, safety, and tolerability. RESULTS A total of 711 patients were enrolled, and 702 received blinded study drug. Ridaforolimus treatment led to a modest, although significant, improvement in PFS per independent review compared with placebo (hazard ratio [HR], 0.72; 95% CI, 0.61 to 0.85; P = .001; median PFS, 17.7 v 14.6 weeks). Ridaforolimus induced a mean 1.3% decrease in target lesion size versus a 10.3% increase with placebo (P < .001). Median OS with ridaforolimus was 90.6 weeks versus 85.3 weeks with placebo (HR, 0.93; 95% CI, 0.78 to 1.12; P = .46). Adverse events (AEs) more common with ridaforolimus included stomatitis, infections, fatigue, thrombocytopenia, noninfectious pneumonitis, hyperglycemia, and rash. Grade ≥ 3 AEs were more common with ridaforolimus than placebo (64.1% v 25.6%). CONCLUSION Ridaforolimus delayed tumor progression to a small statistically significant degree in patients with metastatic sarcoma who experienced benefit with prior chemotherapy. Toxicities were observed with ridaforolimus, as expected with mTOR inhibition. These data provide a foundation on which to further improve control of sarcomas.

Structure-Guided Blockade of CSF1R Kinase in Tenosynovial Giant-Cell Tumor

BACKGROUND Expression of the colony-stimulating factor 1 (CSF1) gene is elevated in most tenosynovial giant-cell tumors. This observation has led to the discovery and clinical development of therapy targeting the CSF1 receptor (CSF1R). METHODS Using x-ray co-crystallography to guide our drug-discovery research, we generated a potent, selective CSF1R inhibitor, PLX3397, that traps the kinase in the autoinhibited conformation. We then conducted a multicenter, phase 1 trial in two parts to analyze this compound. In the first part, we evaluated escalations in the dose of PLX3397 that was administered orally in patients with solid tumors (dose-escalation study). In the second part, we evaluated PLX3397 at the chosen phase 2 dose in an extension cohort of patients with tenosynovial giant-cell tumors (extension study). Pharmacokinetic and tumor responses in the enrolled patients were assessed, and CSF1 in situ hybridization was performed to confirm the mechanism of action of PLX3397 and that the pattern of CSF1 expression was consistent with the pathological features of tenosynovial giant-cell tumor. RESULTS A total of 41 patients were enrolled in the dose-escalation study, and an additional 23 patients were enrolled in the extension study. The chosen phase 2 dose of PLX3397 was 1000 mg per day. In the extension study, 12 patients with tenosynovial giant-cell tumors had a partial response and 7 patients had stable disease. Responses usually occurred within the first 4 months of treatment, and the median duration of response exceeded 8 months. The most common adverse events included fatigue, change in hair color, nausea, dysgeusia, and periorbital edema; adverse events rarely led to discontinuation of treatment. CONCLUSIONS Treatment of tenosynovial giant-cell tumors with PLX3397 resulted in a prolonged regression in tumor volume in most patients. (Funded by Plexxikon; ClinicalTrials.gov number, NCT01004861.).

Phospho-S6 ribosomal protein : a potential new predictive sarcoma marker for targeted mTOR therapy

Metastatic sarcomas are commonly resistant to chemotherapy. The serine/threonine kinase, mammalian target of rapamycin (mTOR), is a protein kinase of the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway thought to have a key role in controlling cancer growth and thus is an important target for cancer therapy. Several inhibitors of mTOR are in clinical trials, including AP23573, which is being tested on metastatic sarcomas and other tumors. We hypothesized that a marker for the activity of mTOR, phosphorylated S6 ribosomal protein, would be predictive of clinical response to the drug, that is, high tumor expression would signify better response than low expression. This was a blinded study. Of 26 patients treated, 20 remained on study, with available paraffin blocks. Fourteen patients received AP23573 alone and six patients received AP23573 in combination with adriamycin. An antibody to the phosphorylated S6 ribosomal protein was used to stain the tumors, all high-grade sarcomas. Pretreatment biopsy or resection material was tested: the original tumor (n=6) or tumor recurrence/metastasis (n=14); either of these may have been after treatment with other agents. Staining was scored for both quantity/percentage of tumor cells and intensity. Scoring was performed without knowledge of tumor response. Staining quantity could be categorized into two natural groups: high expressors (≥20% of tumor cells, 11 cases) and low expressors (0–10% of tumor cells, 9 cases). The high-expression group had eight stable and three progressive cases (73% stable disease); the low-expression group had three stable and six progressive cases (67% progressive disease). Chi-square analysis showed statistical significance (P≤0.05) at this initial cutoff (10%) selected blindly. The level of phosphorylated S6 ribosomal protein expression was predictive of early tumor response to the mTOR inhibitor, suggesting that this is a promising new predictive sarcoma marker for targeted mTOR inhibitor therapy.

Randomised phase III trial of trabectedin versus doxorubicin-based chemotherapy as first-line therapy in translocation-related sarcomas

AIM This randomised phase III trial evaluated first-line trabectedin versus doxorubicin-based chemotherapy (DXCT) in patients with advanced/metastatic translocation-related sarcomas (TRS). METHODS Patients were randomly assigned (1:1) to receive trabectedin 1.5mg/m2 24-h intravenous (i.v.) infusion every 3 weeks (q3wk) (Arm A), or doxorubicin 75 mg/m2 i.v., q3wk, or doxorubicin 60 mg/m2 i.v. plus ifosfamide (range, 6-9 g/m2) i.v. q3wk (Arm B). Progression-free survival (PFS) by independent review was the primary efficacy end-point. RESULTS One hundred and twenty-one patients were randomised; 88 of them had TRS confirmed by central pathology review (efficacy population). Twenty-nine PFS events were assessed by independent review (16 with trabectedin; 13 with DXCT). PFS showed non-significant difference between arms (stratified log rank test, p=0.9573; hazard ratio=0.86, p=0.6992). At the time of this analysis, 63.9% and 58.3% of patients were alive in trabectedin and DXCT arms, respectively. There was no statistically significant difference in survival curves. Response rate according to Response Evaluation Criteria in Solid Tumours (RECIST) v.1.0 was significantly higher in DXCT arm (27.0% versus 5.9%), but response according to Choi criteria showed fewer differences between treatment arms (45.9% versus 37.3%). Safety profile was as expected for both arms, with higher incidence of severe neutropenia, alopecia and mucositis in the DXCT arm. CONCLUSION Neither trabectedin nor doxorubicin-based chemotherapy showed significant superiority in the first-line treatment of patients with advanced translocation-related sarcoma.

Improved Survival after Pulmonary Metastasectomy for Soft Tissue Sarcoma

Introduction:Survival after pulmonary metastasectomy for soft tissue sarcoma (STS) has been lower than in osteosarcoma (14–40% versus 40–50%). With improved patient selection criteria and advanced chemotherapy agents, we hypothesized that survival after metastasectomy for STS has improved in recent years. Methods:Retrospective study of 48 patients undergoing pulmonary metastasectomy for STS between 1995 and 2007. Potential predictors of overall survival and disease-free survival (DFS) were examined using the log-rank test or Cox regression. Multivariate analysis was conducted using Cox regression. Results:Overall survival after initial metastasectomy was 67% and 52% at 3 and 5 years, respectively; DFS was 17% and 10% at 3 and 5 years. Univariate analysis indicated that ≤2 pulmonary metastases (p = 0.03), diameter of largest metastasis ≤2 cm (p = 0.09), and the absence of extrapulmonary metastases (p = 0.10) were associated with longer overall survival. Absence of extrapulmonary metastases (p = 0.07) and smaller size of the largest pulmonary metastasis (p = 0.06) were associated with longer DFS. Before 2001, 46.7% of patients received adjuvant chemotherapy versus 72.7% after (p = 0.10). Neither use of chemotherapy nor chemotherapy type was related to overall survival or DFS. Conclusion:Five-year overall survival is substantially higher after pulmonary metastasectomy for STS in our study relative to previously published results (52% versus 14–40%). This improvement does not seem to be the result of greater use of, or newer, chemotherapeutic regimens. Among potential explanations, improved patient selection is the most likely factor.

Early outcomes for malignant peripheral nerve sheath tumor treated with chemotherapy

Objectives:Malignant peripheral nerve sheath tumors (MPNST) are rare soft-tissue sarcomas with a tendency for recurrence and metastasis. Treatment using chemotherapy is controversial, but benefit with some agents has been described. This study aimed to analyze early survival outcomes using doxorubicin and ifosfamide chemotherapy for MPNST. Methods:Pathology records at our musculoskeletal tumor center were searched for patients with a new diagnosis of MPNST between 2003 and 2008. Treatment involved surgical resection, radiation, and chemotherapy with doxorubicin and ifosfamide. Ten patients met inclusion criteria, with mean age 40 years (range, 20–70). Four patients had metastatic disease on presentation. Four patients had neurofibromatosis type I (NF1). Results:Of 6 patients with nonmetastatic disease on presentation, 5 had no evidence of disease post-treatment. The sixth had positive margins after surgery and initially received no further treatment due to noncompliance. Three from this subgroup developed local recurrence, but none developed distant metastases and 1 died of disease at last follow-up. One- and 2-year disease-free survival (DFS) for this subgroup was 80% and 60%, respectively. One- and 2-year overall survival (OS) for the subgroup was 100%. Of 4 patients with metastatic disease on presentation, 2 had no evidence of disease post-treatment. One of these 2 developed local recurrence, but none from the subgroup developed new metastatic disease. Two of these 4 died of disease at last follow-up. One- and 2-year DFS for this subgroup was 100% and 50%, respectively. One- and 2-year OS was 75% and 50%, respectively. Two of the 4 patients presenting with metastatic disease had NF1. All 3 local recurrences and 2 of the 3 deaths in this study occurred in NF1 patients. Conclusions:For all patients, when combined with surgery and radiation, chemotherapy using doxorubicin and ifosfamide yielded 57% DFS and 80% OS at 2 years. NF1 patients appeared to have worse outcomes, with a statistically significantly lower DFS than non-NF1 patients. Limitations of this study include a small sample size, retrospective design, and use of different chemotherapy regimens.

Effects of denosumab on pain and analgesic use in giant cell tumor of bone: Interim results from a phase II study

Abstract Background. Giant cell tumor of bone (GCTB) is an aggressive primary osteolytic tumor. GCTB often involves the epiphysis, usually causing substantial pain and functional disability. Denosumab, a fully human monoclonal antibody against receptor activator of nuclear factor κΒ ligand (RANKL), is an effective treatment option for patients with advanced GCTB. This analysis of data from an ongoing, open-label study describes denosumabs effects on pain and analgesic use in patients with GCTB. Material and methods. Patients with unresectable disease (e.g. sacral or spinal GCTB, or multiple lesions including pulmonary metastases) were enrolled into Cohort 1 (N = 170), and patients with resectable disease whose planned surgery was associated with severe morbidity (e.g. joint resection, limb amputation, or hemipelvectomy) were enrolled into Cohort 2 (N = 101). Patients received denosumab (120 mg) subcutaneously every four weeks, with additional doses on study days 8 and 15. Patients assessed worst pain severity with the Brief Pain Inventory – Short Form (BPI-SF) at baseline, at each visit for the first six months, and every three months thereafter. Results. Clinically relevant pain improvement was reported by 29% of patients in Cohort 1 and 35% in Cohort 2 during week 1 and by ≥ 50% of patients in each cohort at each study visit from months 2–30. Median time to clinically relevant improvement was 30 (95% CI 16, 57) days in Cohort 1 and 15 (95% CI 15, 29) days in Cohort 2. Results in patients with moderate/severe pain at baseline were similar. Fewer than 30% of patients in Cohort 1 and 10% in Cohort 2 experienced clinically relevant pain worsening at any visit through 27 months. Most patients had no/low analgesic use during the study. Conclusion. Most patients treated with denosumab experienced clinically relevant decreases in pain within two months.