Phase II study of paclitaxel in patients with previously treated osteosarcoma and its variants

Anoikis patterns exhibit distinct prognostic and immune landscapes in Osteosarcoma

OBJECTIVES

Osteosarcoma is highly aggressive and prone to metastasis, with a poor prognosis. Increasing evidence identified anoikis has a critical effect in tumor metastasis and invasion. However, the prognostic value of anoikis-related genes (ANRGs) in osteosarcoma and their role in the immune landscape of osteosarcoma remain unclear.

METHODS

The RNA sequencing and clinical data of patients with osteosarcoma were extracted from the TARGET and GEO databases, and ANRGs were identified from the GeneCards database. Unsupervised clustering analysis was employed to identify anoikis-related patterns. The ESTIMATE, TIMER and ssGSEA algorithms were used to assess the immune microenvironment of different subtypes. A prognostic signature based on the identified ANRGs was constructed via univariate, LASSO and multivariate Cox regression analyses. KEGG, GO and GSEA were used for functional enrichment of genes associated with different risk subtypes. qPCR, WB and IHC were used to validate the expression of candidate genes.

RESULTS

Two anoikis-related patterns with distinct clinical features and immune statuses were identified based on prognosis-related ANRGs. Cluster 2 had more active immunogenicity and a better prognosis than Cluster 1. Subsequently, we developed and validated an anoikis prognostic signature demonstrating excellent predictive ability for the prognosis of osteosarcoma. Anoikis risk score was positively associated with osteosarcoma metastasis and was identified as an independent prognostic marker. Additionally, a nomogram was established to predict the 3- and 5-year survival probability of patients with osteosarcoma. Functional enrichment analysis revealed that immune dysregulation was correlated with poor prognosis. Besides, patients in the low-risk group had higher infiltration levels of immune cells and more active immune function than patients in the high-risk group. Drug sensitivity analysis revealed several chemotherapeutic agents for the treatment of different subtypes of osteosarcoma.

CONCLUSION

Our study demonstrated the role of ANRGs in osteosarcoma progression, providing insights into clinical decision making in osteosarcoma.

Concurrent paclitaxel and radiation therapy for the treatment of cutaneous angiosarcoma

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Cutaneous angiosarcoma has poor outcomes with no standardized treatment regimen.

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Paclitaxel-based chemoRT (CRT) was compared to other therapies at two US institutions.

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Similar oncologic outcomes and improved survival with paclitaxel CRT.

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Paclitaxel CRT + surgery provided best oncologic outcomes and survival.

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Paclitaxel CRT + surgery regimen now being studied in a prospective phase II trial.

Introduction

We compared clinical outcomes in patients with cutaneous angiosarcoma receiving concurrent paclitaxel-based chemoradiotherapy (CRT) vs. other modalities (Non-CRT).

Materials and methods

Patients with non-metastatic cutaneous angiosarcoma diagnosed from 1998 to 2018 at two institutions were identified. In the CRT cohort, paclitaxel 80 mg/m² weekly was given for up to 12 weeks and patients received radiotherapy (RT) during the final 6 weeks of chemotherapy. The RT dose was 50–50.4 Gy delivered in 1.8–2 Gy per fraction with an optional post-operative boost of 10–16 Gy. Kaplan-Meier and log-rank statistics were used to compare the outcomes between the two groups. P < 0.05 was considered statistically significant.

Results

Fifty-seven patients were included: 22 CRT and 35 Non-CRT. The CRT cohort had more patients > 60 years (100% vs. 60%, p < 0.001) and tumors >5 cm (68.2% vs 54.3%, p = 0.023). The median follow-up was 25.8 (1.5–155.2) months. There was no significant difference in 2-year local control (LC), distant control (DC), or progression-free survival (PFS) between the two groups. The 2-year overall survival (OS) was significantly higher for the CRT cohort (94.1% vs. 71.6%, p = 0.033). Amongst the subset of patients in the CRT cohort who received trimodality therapy, the 2-year LC, DC, PFS, and OS was 68.6%, 100%, 68.6%, and 100%, respectively.

Conclusion

The use of concurrent paclitaxel CRT demonstrates promising outcomes. Given these results, we are currently evaluating the safety and efficacy of this regimen in prospective, phase 2 trial (NCT 03921008).

Hydroxyapatite-Bovine Serum Albumin-Paclitaxel Nanoparticles for Locoregional Treatment of Osteosarcoma

Osteosarcoma is the most primary type of bone tumor occurring in the pediatric and adolescent age groups. In order to obtain the most appropriate prognosis, both tumor recurrence inhibition and bone repair promotion are required. In this study, a ternary nanoscale biomaterial/antitumor drug complex including hydroxyapatite (HA), bovine serum albumin (BSA) and paclitaxel (PTX) is prepared for post-surgical cancer treatment of osteosarcoma in situ. The HA-BSA-PTX nanoparticles, about 55 nm in diameter with drug loading efficiency (32.17 wt%), have sustained release properties of PTX and calcium ions (Ca²⁺ ) and low cytotoxicity to human fetal osteoblastic (hFOB 1.19) cells in vitro. However, for osteosarcoma (143B) cells, the proliferation, migration, and invasion ability are significantly inhibited. The in situ osteosarcoma model studies demonstrate that HA-BSA-PTX nanoparticles have significant anticancer effects and can effectively inhibit tumor metastasis. Meanwhile, the detection of alkaline phosphatase activity, calcium deposition, and reverse transcription-polymerase chain reaction proves that the HA-BSA-PTX nanoparticles can promote the osteogenic differentiation. Therefore, the HA-BSA-PTX nanodrug delivery system combined with sustained drug release, antitumor, and osteogenesis effects is a promising agent for osteosarcoma adjuvant therapy.

Albumin-bound paclitaxel and gemcitabine combination therapy in soft tissue sarcoma

BACKGROUND

The evidence that albumin-bound paclitaxel (nab-paclitaxel) is safe and efficacious for the treatment of many types of malignant tumors is continuously increasing. However, the evidence and clinical data of nab-paclitaxel and gemcitabine in metastatic soft tissue sarcoma (STS) treatment are rare.

METHODS

The clinical data of metastatic STS patients who received nab-paclitaxel/ gemcitabine chemotherapy between January 2019 and February 2020 were retrospectively analysed. All these patients were treated with nab-paclitaxel/ gemcitabine only after doxorubicin-based chemotherapy had failed. We evaluated the effectiveness and safety of nab-paclitaxel and gemcitabine in these patients.

RESULTS

A total of 17 patients treated with nab-paclitaxel/ gemcitabine were enrolled in this study. One patient with angiosarcoma achieved complete response, 6 patients had partial response, 5 patients achieved stable disease, and 5 patients had progressive disease. The average diameter change in target lesion from baseline was - 19.06 ± 45.74%. And median progression free survival was 6 months (95% CI, 2-9 months). Grade 3 / 4 adverse events were not common, included neutropenia (17.6%), fatigue (11.8%), anemia (11.8%), leukopenia (11.8%), nausea (5.9%), peripheral neuropathy (5.9%), diarrhea (5.9%), and thrombocytopenia (5.9%). No treatment-related deaths occurred.

CONCLUSION

Nab-paclitaxel/ gemcitabine combination chemotherapy is comparatively effective in the treatment of STS, demonstrates low toxicity, and is worthy of further study.

Low-dose eribulin reduces lung metastasis of osteosarcoma in vitro and in vivo

Lung metastasis markedly reduces the prognosis of osteosarcoma. Moreover, there is no effective treatment for lung metastasis, and a new treatment strategy for the treatment of osteosarcoma lung metastasis is required. Therefore, in this study, we investigated the suppressive effect of the microtubule inhibitor eribulin mesylate (eribulin) on lung metastasis of osteosarcoma. At concentrations >proliferation IC₅₀, eribulin induced cell cycle arrest and apoptosis in a metastatic osteosarcoma cell line, LM8. However, at concentrations <proliferation IC₅₀, (low dose), eribulin changed cell morphology and decreased LM8 migration. Low eribulin concentrations also reduced directionality during migration, peripheral localization of adenomatous polyposis coli protein, and turnover of focal adhesions. In a three-dimensional collagen culture system, low eribulin concentrations inhibited tumor cell proliferation and colony formation. Higher doses of eribulin administered on a standard schedule inhibited lung metastasis and primary tumor growth in a murine osteosarcoma metastasis model. Frequent low-dose eribulin administration (0.3 mg/kg every 4 days × 4) effectively inhibited lung metastasis but had little effect on primary tumor growth. Overall, our results indicate that eribulin could reduce osteosarcoma lung metastasis.

Functionalized Keratin as Nanotechnology-Based Drug Delivery System for the Pharmacological Treatment of Osteosarcoma

Osteosarcoma therapy might be moving toward nanotechnology-based drug delivery systems to reduce the cytotoxicity of antineoplastic drugs and improve their pharmacokinetics. In this paper, we present, for the first time, an extensive chemical and in vitro characterization of dual-loaded photo- and chemo-active keratin nanoparticles as a novel drug delivery system to treat osteosarcoma. The nanoparticles are prepared from high molecular weight and hydrosoluble keratin, suitably functionalized with the photosensitizer Chlorin-e6 (Ce6) and then loaded with the chemotherapeutic drug Paclitaxel (PTX). This multi-modal PTX-Ce6@Ker nanoformulation is prepared by both drug-induced aggregation and desolvation methods, and a comprehensive physicochemical characterization is performed. PTX-Ce6@Ker efficacy is tested on osteosarcoma tumor cell lines, including chemo-resistant cells, using 2D and 3D model systems. The single and combined contributions of PTX and Ce6 is evaluated, and results show that PTX retains its activity while being vehiculated through keratin. Moreover, PTX and Ce6 act in an additive manner, demonstrating that the combination of the cytostatic blockage of PTX and the oxidative damage of ROS upon light irradiation have a far superior effect compared to singularly administered PTX or Ce6. Our findings provide the proof of principle for the development of a novel, nanotechnology-based drug delivery system for the treatment of osteosarcoma.

Pharmacogenomics of second-line drugs used for treatment of unresponsive or relapsed osteosarcoma patients

Second-line treatment of high-grade osteosarcoma (HGOS) patients is based on different approaches and chemotherapy protocols, which are not yet standardized. Although several drugs have been used in HGOS second-line protocols, none of them has provided fully satisfactory results and the role of rescue chemotherapy is not well defined yet. This article focuses on the drugs that have most frequently been used for second-line treatment of HGOS, highlighting the present knowledge on their mechanisms of action and resistance and on gene polymorphisms with possible impact on treatment sensitivity or toxicity. In the near future, validation of the so far identified candidate genetic biomarkers may constitute the basis for tailoring treatment by taking the patients' genetic background into account.

Preclinical evaluation of nanoparticle albumin-bound paclitaxel for treatment of pediatric bone sarcoma

The combination of docetaxel and gemcitabine is frequently used to treat recurrent bone sarcoma. Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) is less toxic and more active than docetaxel or paclitaxel for breast cancer patients. The combination of nab-paclitaxel and gemcitabine has preclinical synergy and is approved to treat pancreatic cancer. We observed growth inhibition and improved survival with nab-paclitaxel in a Ewing sarcoma xenograft, and activity was additive with gemcitabine in an osteosarcoma model. Primary Ewing sarcoma tumors expressed the transport protein SPARC, previously associated with nab-paclitaxel activity. These findings provide rationale for further evaluation of nab-paclitaxel with gemcitabine for bone sarcoma.

Exploration of paclitaxel (Taxol) as a treatment for malignant tumors in cats: a descriptive case series

Paclitaxel, an effective chemotherapeutic agent in human oncology, has received little evaluation in feline patients. The diluent used to solubilize paclitaxel, polyoxyethylated castor oil (Cremophor EL), causes anaphylactoid reactions in human and dogs, which limits enthusiasm for use of this agent in veterinary oncology. Nine feline patients with measurable malignant tumors were treated with paclitaxel at a dosage of 80 mg/m(2) intravenously every 21 days for up to two doses. Adverse effects, including evidence of toxicity and anaphylactoid reactions, were assessed. Tumor response, progression and patient time to progression (TTP) were also recorded. Adverse effects included grade III and IV thrombocytopenia, grade III gastrointestinal signs (vomiting and constipation) and hypersensitivity reactions, seen in a total of five patients. Anaphylactoid reactions resolved with appropriate management. Stable disease and partial response were observed in 56% of feline patients. Median TTP was 28 days (range 15-45 days). Intravenous paclitaxel is a safe treatment option for feline malignant tumor patients. Future investigation is warranted to explore the effectiveness and appropriate application of this agent for specific tumor types.

Cell-cycle synchronization reverses Taxol resistance of human ovarian cancer cell lines

Background

Taxol is a powerful chemotherapy agent leading to mitotic arrest and cell death; however, its clinical efficacy has been hampered due to the development of drug resistance. Taxol specifically targets the cell cycle. Progress through mitosis (M stage) is an absolute requirement for drug-induced death because cell death is markedly reduced in cells blocked at the G₁-S transition. The measured doubling time for ovarian cancer cells is about 27 h. As such, during treatment with Taxol most of the cells are not in the M stage of the cell cycle. Thus, the effect of cell-cycle synchronization was investigated in regard to reversing Taxol resistance in ovarian cancer cells.

Methods

Giemsa-Wright staining was used for assessing the morphology of the cells. The doubling time of the cells was calculated using formula as follows: Td = In2/slope. The resistant index and cell cycle were measured via MTT assays and flow cytometry. Thymidine was used to induce cell-cycle synchronization, and cell apoptosis rates following exposure to Taxol were measured using a flow cytometer.

Results

The growth doubling time of two Taxol-resistant cell lines were longer than that of Taxol-sensitive cells. Apoptotic rates in Taxol-sensitive and -resistant cell lines after synchronization and exposure to Taxol were all higher compared to unsynchronized controls (p <0.05).

Conclusions

Synchronization of the cell-cycle resulted in an increased effectiveness of Taxol toward ovarian cancer cell lines. We speculated that formation of drug resistance toward Taxol in ovarian cancer could be partly attributed to the longer doubling time of these cells.

The efficacy of abraxane on osteosarcoma xenografts in nude mice and expression of secreted protein, acidic and rich in cysteine

BACKGROUND

Although there have been previous efforts to optimize dose intensity or change the chemotherapy protocol for osteosarcoma, long-term survival has not been markedly improved during the past 15 years.

METHOD

Nude mice bearing established OS-732 human osteosarcoma received varying doses of Adriamycin, paclitaxel and Abraxane to assess tumor growth inhibition. For the dose-response experiments, mice were treated with the following agents at the indicated doses: (A) Adriamycin (2.5 mg/kg, ip), (B) paclitaxel (20 mg/kg, ip), (C-E) Abraxane (10, 20 and 40 mg/kg, ip, respectively) and (F) Saline (20 mg/kg, ip). All agents were administered every 4 days. Mean tumor volume and mice weight measurements were recorded every 3 days. Tumor weights were examined after mice were killed. Real-time polymerase chain reaction and Western blot were used to detect the expression levels of secreted protein, acidic and rich in cysteine (SPARC) in osteosarcoma specimens.

RESULTS

Administration of 40 mg/kg Abraxane showed a tumor inhibitory rate of 98.8% (tumor weight, 0.033 ± 0.044 g, P < 0.01), which was significantly higher than Adriamycin (46.1%, tumor weight, 1.455 ± 1.115 g, P < 0.01) and paclitaxel (40.8%, tumor weight, 1.597 ± 1.834 g, P < 0.05). Real-time polymerase chain reaction and Western blot showed higher expression of SPARC in tumor tissues than in normal tissues.

CONCLUSION

The antitumor effect of Abraxane was demonstrated in osteosarcoma xenografts in vivo. It suggests that SPARC tends to be highly expressed in osteosarcoma and further experiments need to explore its clinical relevance and the possible mechanisms.

Comprehensive analysis of published phase I/II clinical trials between 1990-2010 in osteosarcoma and Ewing sarcoma confirms limited outcomes and need for translational investment

Background

High grade primary bone sarcomas are rare cancers that affect mostly children and young adults. Osteosarcoma and Ewing sarcoma are the most common histological subtypes in this age group, with current multimodality treatment strategies achieving 55-70% overall survival. As there remains an urgent need to develop new therapeutic interventions, we have reviewed published phase I/II trials that have been reported for osteosarcoma and Ewing sarcoma in the last twenty years.

Results

We conducted a literature search for clinical trials between 1990 and 2010, either for trials enrolling bone sarcoma patients as part of a general sarcoma indication or trials specifically in osteosarcoma and Ewing sarcoma. We identified 42 clinical trials that fulfilled our search criteria for general sarcoma that enrolled these patient groups, and eight and twenty specific trials for Ewing and osteosarcoma patients, respectively. For the phase I trials which enrolled different tumour types our results were incomplete, because the sarcoma patients were not mentioned in the PubMed abstract. A total of 3,736 sarcoma patients were included in these trials over this period, 1,114 for osteosarcoma and 1,263 for Ewing sarcoma. As a proportion of the worldwide disease burden over this period, these numbers reflect a very small percentage of the potential patient recruitment, approximately 0.6% for Ewing sarcoma and 0.2% for osteosarcoma. However, these data show an increase in recent activity overall and suggest there is still much room for improvement in the current trial development structures.

Conclusion

Lack of resources and commercial investment will inevitably limit opportunity to develop sufficiently rapid improvements in clinical outcomes. International collaboration exists in many well founded co-operative groups for phase III trials, but progress may be more effective if there were also more investment of molecular and translational research into disease focused phase I/II clinical trials. Examples of new models for early translational and early phase trial collaboration include the European based EuroBoNeT network, the Sarcoma Alliance for Research through Collaboration network (SARC) and the new European collaborative translational trial network, EuroSarc.

Metastatic osteosarcoma: a review of current issues in systemic treatment

Purpose. Original articles and abstracts published between January 1991 and January 1997 were selected according to specified criteria and reviewed to provide answers to five interesting questions about the systemic treatment of metastatic osteosarcoma.

Results.

(1) In patients with metastatic disease at presentation, what is the outcome after intensive multi-agent chemotherapy?

Historically, survival has been poor, but may be improving with the use of ifosfamide-containing regimens.

(2) Can response to new agents be evaluated better in patients who have received no previous chemotherapy?

Based on limited data, this is probably true.

(3) Is the response to neo-adjuvant chemotherapy, as determined by histopathology, similar for the primary tumor and synchronous pulmonary metastases?

With intensive multi-agent chemotherapy, good histological response rates are in the range 70–90% for both groups.

(4) What is the outcome, after intensive combined modality treatment with chemotherapy and surgery, in patients relapsing with metastases after previous adjuvant chemotherapy, and what are the important prognostic factors?

Outcome is highly variable, but 5-year survival ranges between 25 and 50% and a good outcome is more likely if recurrent disease is limited to resectable lung metastases.

(5) Can a biological agent (L-MTP-PE) prolong the time to relapse in patients with resected metastatic osteosarcoma?

Preliminary data suggest that this is possible, but more studies are required.

A Phase II Study of Docetaxel for the Treatment of Recurrent Osteosarcoma

Purpose: To determine the response and toxicity of docetaxel in recurrent osteosarcoma and related spindle cell tumours of bone.

Patients and methods: Fourteen patients, 10 males and four females, were enrolled, median age 30.5 years (range, 17–46). Diagnosis was: conventional osteosarcoma, 12 patients; periosteal osteosarcoma, one patient; and malignant fibrous histiocytoma of bone, one patient. Initial chemotherapy had been with doxorubicin and cisplatin in 10 patients, and multiagent regimens in four. Nine had been treated with second line chemotherapy before receiving docetaxel. Thirteen patients had lung metastases and one intra-abdominal disease. Docetaxel 100 mg/mα² was given as a 1-h infusion every 3 weeks. Response was assessed every two cycles to a maximum of six.

Results: A total of 43 cycles were given, median of two per patient (range 1–6). Thirteen patients were evaluable for response. A single partial remission was seen, for a response rate of 8%. Two patients had stable disease, and one patient a mixed response. Forty cycles were evaluable for toxicity. The principle toxicity was haematological, with a median neutrophil count of 0.9 (range 0–9.6). There were four episodes of neutropenic sepsis (10%). The only non-haematological toxicity ≥grade 3 was stomatitis, occurring in just one patient. There were no toxic deaths.

Conclusion: Docetaxel at this dose and schedule is well tolerated, but is not associated with significant activity in patients with relapsed osteosarcoma.

Phase II Study of Paclitaxel in Patients With Soft Tissue Sarcomas

Purpose. Patients with soft tissue sarcoma (STS) who have previously received standard chemotherapy including adriamycin (doxorubicin), ifosfamide, cyclophosphamide and DTIC (dacarbazine) have very limited therapeutic options. It is important to identify new drugs with some activity in this disease and we therefore undertook this trial to determine the antitumor activity of paclitaxel (Taxol).Methods. We conducted a phase II study of paclitaxel in patients with STS who had received prior standard chemotherapy. Paclitaxel was administered at a starting dose of 200 mg m(-2) as a 24-h infusion with STS premedication, every 21 days or upon hematologic recovery (absolute granulocyte count (AGC) >/= 1500/mul, platelets >/= 100 000/mul). Neupogen was not used routinely. The study was conducted based on a two-stage design proposed by Simon. Responses were assessed radiographically using standard criteria.Results. Nineteen eligible patients were treated in the first stage of the study. The median age was 50 years (range 20-68 years), and there were nine females and 10 males with Zubrod performance status of 1 or 2. One patient achieved a minor response. Median AGC nadir was 0.1/mul on day 12 with absolute neutropenia lasting 5 days. Median platelet nadir was 171 000/mul on day 9. There were no grade 3/4 non-hematologic toxicities and no deaths related to treatment.Discussion. Paclitaxel, at this dose and schedule, is well tolerated but inactive in this patient population.

Management of osteosarcoma

Improving cure rates for osteosarcoma continues to be a major challenge. The clinical management of individual patients is exacting and requires a skilled, experienced team including a surgeon, pathologist, oncologist, and radiologist, with support from specialist nurses and rehabilitation teams. Outcomes from treatment have improved little in 20 years and remain disappointing. Chemotherapy for osteosarcoma is among the most grueling of any given for solid tumors, and treatment of the primary tumor is associated with permanent disability of some degree in a significant proportion of patients. New systemic treatments remain beyond the horizon. In recognition of these difficulties, an international cooperation has begun with the opening of a randomized trial, European and American Osteosarcoma (EURAMOS) 1, in Europe and the United States. This study heralds a new era of clinical investigation into osteosarcoma, with the promise of valuable biologic insights and rapid evaluation of investigational strategies. Osteosarcoma should always be treated under the guidance of a specialist team, and we recommend that whenever possible, patients be offered entry into EURAMOS 1 or other well-designed clinical trials.

Isolated lung perfusion for pulmonary metastases

Isolated lung perfusion is an experimental surgical technique evaluated for the delivery of high-dose chemotherapy to improve 5-year survival after pulmonary metastasectomy. Extensive experimental work in animal models has demonstrated superior pharmacokinetics and efficacy compared with systemic therapy. Phase I clinical trials of isolated lung perfusion found a maximum tolerated dose**** of TNF-alpha, doxorubicin, cisplatin, and melphalan, whereas the combination of isolated lung perfusion with a complete metastasectomy was feasible. The combination of isolated lung perfusion and regional lung perfusion techniques needs further investigation.

Inactivation of the mitotic checkpoint as a determinant of the efficacy of microtubule-targeted drugs in killing human cancer cells

Drugs that disrupt microtubule dynamics include some of the most important of cancer chemotherapies. While these drugs, which include paclitaxel (Taxol), are known to invoke the mitotic checkpoint, the factors that determine cancer cell killing remain incompletely characterized. Cells that are relatively resistant to killing by these drugs block robustly in mitosis, whereas cells sensitive to killing block only transiently in mitosis before undergoing nuclear fragmentation and death. Passage through mitosis was an absolute requirement of drug-induced death, because death was markedly reduced in cells blocked at both G1-S and G2. Cell killing was at least in part linked to the absence or inactivation of BubR1, a kinetochore-associated phosphoprotein that mediates the mitotic checkpoint. Sensitivity to paclitaxel correlated with decreased BubR1 protein expression in human cancer cell lines, including those derived from breast and ovarian cancers. Silencing of BubR1 via RNA interference inactivated the mitotic checkpoint in drug-resistant cells, and reversed resistance to paclitaxel and nocodazole. Together, these results suggest that the mitotic checkpoint is an important determinant of the efficacy of microtubule-targeting drugs in killing cancer cells, potentially providing novel targets for increasing treatment efficacy.

Pharmacokinetics of paclitaxel administered by hyperthermic retrograde isolated lung perfusion techniques

OBJECTIVE

Although paclitaxel is widely used as a systemic agent for the treatment of solid tumors, limited information is available concerning administration of this taxane by regional techniques. The present study was undertaken to evaluate the pharmacokinetics and acute toxicity of paclitaxel administered by hyperthermic retrograde isolated lung perfusion techniques to ascertain its potential for the regional therapy of unresectable pulmonary neoplasms.

METHODS

Adult sheep underwent 90 minutes of retrograde isolated lung perfusion with escalating doses of paclitaxel and moderate hyperthermia using a protein-free, oxygenated extracorporeal circuit and a steady perfusion pressure of 14 to 16 mm Hg. An additional animal received paclitaxel by means of 1-hour central venous infusion. Paclitaxel concentrations in lung tissues, perfusates, and systemic circulation were determined by high-performance liquid chromotography techniques. Cytotoxicity of paclitaxel in cancer cells and in normal human bronchial epithelial cells was evaluated in vitro using 4, 5-dimethylthiazo-2-yl-25-dipagnyl tetrazolium bromide assays. Lung tissues were examined by hematoxylin-and-eosin techniques.

RESULTS

Paclitaxel concentrations (maximum concentration and area under the plasma concentration time curve) in perfused tissues increased with escalating perfusate doses. Uptake of drug into lung parenchyma appeared saturable at high paclitaxel exposure; a substantial pharmacokinetic advantage was observed. Paclitaxel concentrations in systemic circulation were undetectable or exceedingly low after perfusion. Histopathologic examination of lung tissues harvested 3 hours after completion of isolated lung perfusion revealed no immediate toxicity, even at a paclitaxel exposure 20-fold higher than that achievable after 1 hour of intravenous administration at the maximum tolerable dose in human subjects. Moderate hyperthermia enhanced paclitaxel-mediated cytotoxicity 5- to 100-fold in cultured cancer lines. No paclitaxel toxicity was observed in cultured normal human bronchial epithelial cells after exposure to paclitaxel under normothermic or hyperthermic conditions.

CONCLUSIONS

These data support further evaluation of paclitaxel administered by hyperthermic retrograde isolated lung perfusion techniques for the treatment of unresectable malignant pulmonary tumors.

Cancer/testis antigen CSAGE is concurrently expressed with MAGE in chondrosarcoma

Differential display-polymerase chain reaction was used to compare gene expression between human chondrosarcoma cell lines and normal cartilage. A new gene, CSAGE, has been cloned and belongs to a gene family that includes the taxol resistance associated gene (TRAG)-3. CSAGE, like TRAG-3, does not confer resistance to taxol when transfected in vitro. Both genes have alternatively spliced variants. CSAGE and TRAG-3 are expressed in chondrosarcoma, melanoma, and cartilage and testis, but not in other normal tissues. TRAG-3 has been reported to be a cancer/testis antigen. Our results suggest that CSAGE belongs to the growing list of cancer/testis antigens as well. In all of the CSAGE positive samples, the melanoma antigen gene family was also expressed. This is the first report on the expression of cancer/testis antigens in chondrosarcoma.

Selective drug resistant human osteosarcoma cell lines

Chemotherapy in combination with surgery has been shown to be effective for the control of osteosarcoma. Development of resistance to chemotherapeutic agents is a recurring clinical problem. To investigate this phenomena, human osteosarcoma cells, TE-85, were exposed to increasing doses of Taxol or Taxotere during a 9-month period. Highly resistant subclones (TE-85TXL; TE-85TXR, respectively) were developed. Chemosensitivities are presented for TE-85 cell line and these new lines to Taxol, Taxotere, doxorubicin, cisplatin, and topotecan. Drug concentrations that inhibited cell growth by 50% compared with untreated cells were determined. The TE-85TXL cells showed resistance greater than 1,000-fold to Taxol and Taxotere and 60-fold to doxorubicin. The TE-85TXR cells showed resistance greater than 1,000-fold to Taxol, 800-fold to Taxotere, and 90-fold to doxorubicin. There was little cross resistance to topotecan and enhanced sensitivity to cisplatin. The role of P-170 glycoprotein in Taxol and Taxotere resistance was explored. Coincubation with verapamil, to block the actions of P-170 glycoprotein, partly reversed resistance to Taxol, Taxotere, and doxorubicin in both cell lines. Anti-P-170 glycoprotein antibodies revealed positive staining in TE-85TXL and TE-85TXR cell lines. Flow cytometry revealed reduced accumulation of doxorubicin in resistant cells. These data indicate that a human osteosarcoma cell line will develop resistance to Taxol and Taxotere, which is mediated in part by the P-170 glycoprotein.

Phase II trial of paclitaxel in patients with soft-tissue sarcoma

The response rate (RR) to single-agent chemotherapy with doxorubicin or ifosfamide in patients with advanced soft-tissue sarcoma (STS) is in the range of 20%. Paclitaxel is clinically useful in treating several solid tumors and has demonstrated activity in a series of human sarcoma cell lines. Twenty-eight patients with measurable advanced STS participated in this phase II trial of paclitaxel at 250 mg/m2 administered as a 3-hr i.v. infusion once every 3 weeks. All patients received granulocyte colony-stimulating factor (G-CSF) beginning on the day after paclitaxel and lasting until recovery from neutropenia. No prior chemotherapy had been used in 17 patients; 10 patients had had prior doxorubicin-based therapy; and 1 patient had had intraperitoneal therapy with edatrexate. Two partial responses (PRs) (7%; 95% confidence interval [CI] = 1-23%) were observed. The responding patients included a patient with angiosarcoma of the scalp who had complete regression of cutaneous lesions and improvement of nonmeasurable pulmonary disease lasting 6 months. The other PR occurred in a woman with metastatic uterine leiomyosarcoma and lasted 9 months. Seven patients had stable disease for 3-4 months. Median time to progression for all patients was 3.5 months (range: 2.5-9 months). The mean nadir in the white-blood-cell (WBC) count was 3.8 x 10(3)/microliter (range: [0.2-16.2] x 10(3)/microliter), with a mean nadir in the absolute neutrophil count (ANC) of 2.4 x 10(3)/microliter (range: [0.0-7.1] x 10(3)/microliter). Three patients died while in the study. Two patients with angiosarcoma of the scalp who did not qualify for this study were treated with paclitaxel off protocol, and experienced dramatic tumor regression. The overall response to paclitaxel observed in this heterogeneous group of patients was disappointing. However, the activity seen in angiosarcoma of the scalp suggests that further evaluation is warranted in patients with STS.