Sarcoma in patients with Lynch syndrome and response to immunotherapy.

BACKGROUND: Lynch syndrome (LS) is an autosomal dominant genetic predisposition to multiple malignancies and is characterized by deficient DNA mismatch repair. Increased incidence of sarcomas is not formally ascribed to LS; however, increasing evidence suggests a preponderance of these malignancies in affected families. Sarcomas typically possess a low tumor mutational burden and incite a poor immune infiltrate, thereby rendering them poorly responsive to immunotherapy. METHODS: We searched the University of California, Los Angeles (UCLA) sarcoma program database for patients with a diagnosis of sarcoma and LS from 2016 to 2023. Three such patients were identified and all three were treated with PD1 blockade. RESULTS: We present three cases of LS-associated sarcomas (two soft tissue sarcoma and one osteosarcoma) with increased tumor mutational burdens. These patients were each treated with an anti-PD1 antibody and experienced a response far superior to that reported for non-LS-associated sarcomas. CONCLUSIONS: Increased mutational burden and immune infiltrate are observed for sarcomas associated with LS. Although unselected patients with sarcoma have demonstrated poor response rates to immunotherapy, our findings suggest that patients with Lynch-associated sarcomas are more likely to respond to treatment with anti-PD1. These patients should be given consideration for immunotherapy.

Lifelong Imaging Surveillance is Indicated for Patients with Primary Retroperitoneal Liposarcoma.

BACKGROUND: Surveillance imaging of patients with retroperitoneal liposarcoma (RP-LPS) after surgical resection is based on a projected risk of locoregional and distant recurrence. The duration of surveillance is not well defined because the natural history of RP-LPS after treatment is poorly understood. This study evaluated the long-term risk of recurrence and disease-specific survival (DSS) for a cohort of patients with at least 10 years of progression-free survival (10yr-PFS) from their primary resection. METHODS: The prospective University of California, Los Angeles (UCLA) Sarcoma Database identified RP-LPS patients with 10yr-PFS after initial resection. The patients in the 10yr-PFS cohort were subsequently evaluated for recurrence and DSS. The time intervals start at date of initial surgical resection. Cox proportional hazards models were used to determine factors associated with recurrence and DSS. RESULTS: From 1972 to 2010, 76 patients with RP-LPS had at least 10 years of follow-up evaluation. Of these 76 patients, 39 (51%) demonstrated 10yr-PFS. The median follow-up period was 15 years (range 10-33 years). Among the 10yr-PFS patients, 49% (19/39) experienced a recurrence at least 10 years after surgery. Of those who experienced recurrence, 42% (8/19) died of disease. Neither long-term recurrence nor DSS were significantly associated with age, sex, tumor size, LPS subtype, surgical margin, or perioperative treatment with radiation or chemotherapy. CONCLUSION: Patients who have primary RP-LPS treated with surgical resection ± multimodality therapy face a long-term risk of recurrence and disease-specific death unacknowledged by current surveillance imaging guidelines. Among the patients with 10yr-PFS, 49% experienced a recurrence, and 42% of those died of disease. These findings suggest a need for lifelong surveillance imaging for patients with RP-LPS.

Translating Knowledge About the Immune Microenvironment of Gastrointestinal Stromal Tumors into Effective Clinical Strategies.

OPINION STATEMENT: The role of targeted therapy is firmly established for gastrointestinal stromal tumors (GISTs); other modalities for targeting this disease are necessary for recurrent and refractory disease. There are several lines of evidence pointing to an active role of the immune system in GIST. Preclinical and clinical studies revealed that the most common type of immune cell infiltration in GISTs is tumor-associated macrophages (TAMs). The mechanism of how TAMs sculpt the tumor microenvironment in GIST is not clear, but it seems that the presence of immunosuppressive regulatory T cells (Tregs) is correlated with the number of TAMs, thus linking macrophages to immunosuppression. CD3+ T cells and NK infiltrates are found in the GIST microenvironment and carry some prognostic value. In early clinical trials, there is evidence for an active role for immunotherapy in treating GIST patients. Moreover, preclinical evidence has indicated that combining TKIs with checkpoint blockers may be synergistic in murine GIST models. Overall, there is substantial preclinical and clinical evidence to support a role for immunoregulation in GIST and further studies will be important for the development of immunotherapies for GIST.

Kaposi sarcoma in anti-neutrophil cytoplasmic antibody-associated vasculitis: a case-based review.

Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) are systemic necrotizing vasculitides associated with significant morbidity and mortality. Given the immunosuppression used to manage these conditions, it is important for clinicians to recognize complications, especially infectious ones, which may arise during treatment. Kaposi sarcoma (KS) is a lymphoangioproliferative neoplasm caused by human herpes virus 8 (HHV-8). Its cutaneous manifestations can mimic vasculitis. We describe a 77-year-old man with microscopic polyangiitis with pulmonary-renal syndrome treated with prednisone and intravenous cyclophosphamide who developed KS (HHV-8 positive) after 2 months of treatment. Cyclophosphamide was discontinued and prednisone gradually lowered with improvement and clinical stabilization of KS lesions. This comprehensive review includes all published cases of KS in patients with AAV, with a goal to summarize potential risk factors including the clinical characteristics of vasculitis, treatment and outcomes of patients with this rare complication of immunosuppressive therapy. We also expanded our literature review to KS in other forms of systemic vasculitis. Our case-based review emphasizes the importance of considering infectious complications of immunosuppressive therapy, especially glucocorticoids, and highlights the rare association of KS in systemic vasculitis.

Low Rates of Chemotherapy Use for Primary, High-Grade Soft Tissue Sarcoma: A National Cancer Database Analysis.

BACKGROUND: There is conflicting evidence regarding the role of chemotherapy for high-grade soft tissue sarcoma (STS) in adults. We sought to characterize patterns of chemotherapy use, including multiagent and neoadjuvant chemotherapy, in the United States. PATIENTS AND METHODS: Using the National Cancer Database, we identified 19,969 adult patients who underwent surgical resection for primary high-grade STS from 2004 to 2016. Using logistic regression, we examined factors associated with overall, multiagent, and neoadjuvant chemotherapy use. RESULTS: Chemotherapy was administered to 22% (n=4,377) of the study population. Among patients treated using chemotherapy, 85% received multiagent treatment and 47% received neoadjuvant treatment. On multivariate analysis, factors associated with chemotherapy use included tumor size, depth, histology, and primary site; receipt of radiation treatment; younger age; higher patient income; and academic treatment facility. Factors associated with multiagent chemotherapy use included tumor histology, tumor primary site, and younger age. Factors associated with neoadjuvant chemotherapy use included tumor size, depth, margin status, and primary site; receipt of radiation treatment; higher patient income; academic treatment facility type; and distance to treatment facility. Treatment at a high-volume facility was the only factor associated with overall, multiagent, and neoadjuvant chemotherapy use. No significant temporal trend was seen in overall, multiagent, or neoadjuvant chemotherapy use. CONCLUSIONS: Overall chemotherapy use was low (22%). The variability in chemotherapy use was driven by clinical, patient, demographic, and facility factors. Among patients treated with chemotherapy, the use of multiagent chemotherapy was high (85%), and nearly half received neoadjuvant therapy. There was a discrepancy in the use of chemotherapy-including neoadjuvant and multiagent chemotherapy-between high- and low-volume treatment centers.

Temozolomide regresses a doxorubicin-resistant undifferentiated spindle-cell sarcoma patient-derived orthotopic xenograft (PDOX): precision-oncology nude-mouse model matching the patient with effective therapy.

Undifferentiated spindle-cell sarcoma (USCS) is a recalcitrant cancer, resistant to conventional chemotherapy. A patient with high-grade USCS from a striated muscle was implanted orthotopically in the right biceps femoris muscle of mice to establish a patient-derived orthotopic xenograft (PDOX) model. The PDOX models were randomized into the following groups when tumor volume reached 100 mm3 : G1, control without treatment; G2, doxorubicin (DOX) (3 mg/kg, intraperitoneal [i.p.] injection, weekly, for 2 weeks); G3, temozolomide (TEM) (25 mg/kg, p.o., daily, for 14 days). Tumor size and body weight were measured with calipers and a digital balance twice a week. TEM significantly inhibited tumor volume growth compared to the untreated control and the DOX-treated group on day 14 after treatment initiation: control (G1): 343 ± 78 mm3 ; DOX (G2): 308 ± 31 mm3 , P = 0.272; TEM (G3): 85 ± 21 mm3 , P < 0.0001. TEM significantly regressed the tumor volume compared to day 0 (P = 0.019). There were no animal deaths in any group. The body weight of treated mice was not significantly different in any group. Tumors treated with DOX were comprised of spindle-shaped viable cells without apparent necrosis or inflammatory changes. In contrast, tumors treated with TEM showed extensive tumor necrosis. The present study demonstrates the potential power of matching the patient with an effective drug and saving the patient needless toxicity from ineffective drugs.

Tumor-targeting Salmonella typhimurium A1-R arrests a doxorubicin-resistant PDGFRA-amplified patient-derived orthotopic xenograft mouse model of pleomorphic liposarcoma.

Pleomorphic liposarcoma (PLPS) is a recalcitrant soft-tissue sarcoma (STS) subtype in need of transformative therapy. We have previously established a patient-derived orthotopic xenograft (PDOX) model, of PLPS with PDGFRA amplification, using surgical orthotopic implantation. In the current study, the PLPS PDOX model was randomized into 3 groups of 7 mice each: untreated control; doxorubicin (DOX)-treated; and treated with Salmonella typhimurium A1-R (S. typhimurium A1-R) expressing green fluorescent protein (GFP). Tumor volume and body weight were monitored during the treatment period. The PLPS PDOX was resistant to DOX. In contrast, the PLPS PDOX was highly sensitive to S. typhimurium A1-R. There was no significant body-weight loss among these 3 groups. Fluorescence imaging demonstrated that S. typhimurium A1-R-GFP was very effective to target the PLPS PDOX tumor. The current study demonstrates that a PLPS PDOX, resistant to first-line therapy DOX, was highly sensitive to tumor targeting S. typhimurium A1-R.

Eribulin regresses a doxorubicin-resistant Ewing's sarcoma with a FUS-ERG fusion and CDKN2A-deletion in a patient-derived orthotopic xenograft (PDOX) nude mouse model.

Ewing's sarcoma is a recalcitrant tumor greatly in need of more effective therapy. The aim of this study was to determine the efficacy of eribulin on a doxorubicin (DOX)-resistant Ewing's sarcoma patient derived orthotopic xenograft (PDOX) model. The Ewing's sarcoma PDOX model was previously established in the right chest wall of nude mice from tumor resected form the patient's right chest wall. In the previous study, the Ewing's sarcoma PDOX was resistant to doxorubicin (DOX) and sensitive to palbociclib and linsitinib. In the present study, the PDOX models were randomized into three groups when the tumor volume reached 60 mm3 : G1, untreated control (n = 6); G2, DOX treated (n = 6), intraperitoneal (i.p.) injection, weekly, for 2 weeks); G3, Eribulin treated (n = 6, intravenous (i.v.) injection, weekly for 2 weeks). All mice were sacrificed on day 15. Changes in body weight and tumor volume were assessed two times per week. Tumor weight was measured after sacrifice. DOX did not suppress tumor growth compared to the control group (P = 0.589), consistent with the previous results in the patient and PDOX. Eribulin regressed tumor size significantly compared to G1 and G2 (P = 0.006, P = 0.017) respectively. No significant difference was observed in body weight among any group. Our results demonstrate that eribulin is a promising novel therapeutic agent for Ewing's sarcoma.

Growth of doxorubicin-resistant undifferentiated spindle-cell sarcoma PDOX is arrested by metabolic targeting with recombinant methioninase.

Undifferentiated spindle-cell sarcoma (USCS) is a recalcitrant -cancer in need of individualized therapy. A high-grade USCS from a striated muscle of a patient was grown orthotopically in the right biceps femoris muscle of nude mice to establish a patient-derived orthotopic xenograft (PDOX) model. In a previous study, we evaluated the efficacy of standard first-line chemotherapy of doxorubicin (DOX), gemcitabine (GEM) combined with docetaxel (DOC), compared to pazopanib (PAZ), a multi-targeting tyrosine-kinase inhibitor, in an USCS PDOX model. In the present study, mice-bearing the USCS PDOX tumors were randomized into the following groups when tumor volume reached 100 mm3 : G1, untreated control without treatment; G2, DOX (3 mg/kg, intraperitoneal (i.p.) injection, weekly, for 2 weeks); G3, L-methionine α-deamino-γ-mercaptomethane lyase (recombinant methioninase [rMETase]) (100 U/mouse, i.p., daily, for 2 weeks). Tumor size and body weight were measured with calipers and a digital balance twice a week. The methionine level of supernatants derived from sonicated tumors was also measured. rMETase inhibited tumor growth, measured by tumor volume, compared to untreated controls and the DOX-treated group on day 14 after initiation of treatment: control (G1): 347.6 ± 88 mm3 ; DOX (G2): 329.5 ± 79 mm3 , P = 0.670; rMETase (G3): 162.6 ± 51 mm3 , P = 0.0003. The mouse body weight of the treated mice was not significantly different from the untreated controls. Tumor L-methionine levels were reduced after the rMETase-treatment compared to untreated control and pre-rMETase treatment. We previously reported efficacy of rMETase against Ewing's sarcoma and melanoma in a PDOX models. These studies suggest clinical development of rMETase, especially in recalcitrant cancers such as sarcoma.

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.).

Tumor-targeting Salmonella typhimurium A1-R is a highly effective general therapeutic for undifferentiated soft tissue sarcoma patient-derived orthotopic xenograft nude-mouse models.

Undifferentiated soft tissue sarcoma (USTS) is a recalcitrant and heterogeneous subgroup of soft tissue sarcoma with high risk of metastasis and recurrence. Due to heterogeneity of USTS, there is no reliably effective first-line therapy. We have generated tumor-targeting Salmonella typhimurium A1-R (S. typhimurium A1-R), which previously showed strong efficacy on single patient-derived orthotopic xenograft (PDOX) models of Ewing's sarcoma and follicular dendritic cell sarcoma. In the present study, tumor resected from 4 patients with a biopsy-proven USTS (2 undifferentiated pleomorphic sarcoma [UPS], 1 undifferentiated sarcoma not otherwise specified [NOS] and 1 undifferentiated spindle cell sarcoma [USS]) were grown orthotopically in the biceps femoris muscle of mice to establish PDOX models. One USS model and one UPS model were doxorubicin (DOX) resistant. One UPS and the NOS model were partially sensitive to DOX. DOX is first-line therapy for these diseases. S. typhimurium A1-R arrested tumor growth all 4 models. In addition to arresting tumor growth in each case, S. typhimurium A1-R was significantly more efficacious than DOX in each case, thereby surpassing first-line therapy. These results suggest that S. typhimurium A1-R can be a general therapeutic for USTS and possibly sarcoma in general.

Combination therapy of tumor-targeting Salmonella typhimurium A1-R and oral recombinant methioninase regresses a BRAF-V600E-negative melanoma.

Melanoma is a recalcitrant cancer. To improve and individualize treatment for this disease, we previously developed a patient-derived orthotopic xenograft (PDOX) model for melanoma. We previously reported the individual efficacy of tumor-targeting Salmonella typhimurium A1-R (S. typhimurium A1-R) and recombinant methioninase (rMETase) for melanoma in the PDOX models of this disease. In the present study, we evaluated the efficacy of the combination of S. typhimurium A1-R with orally-administered rMETase (o-rMETase) for BRAF-V600E-negative melanoma in a PDOX model. Three weeks after implantation, 60 PDOX mouse models were randomized into six groups of 10 mice each: untreated control, temozolomide (TEM); o-rMETase; S. typhimurium A1-R; TEM + rMETase, S. typhimurium A1-R + rMETase. All treatments inhibited tumor growth compared to untreated control (TEM: p < 0.0001, rMETase: p < 0.0001, S. typhimurium A1-R: p < 0.0001, TEM + rMETase: p < 0.0001, S. typhimurium A1-R + rMETase: p < 0.0001). The most effective was the combination of S. typhimurium A1-R + o-rMETase which regressed this melanoma PDOX, thereby indicating a new paradigm for treatment of metastatic melanoma.

Metabolic targeting with recombinant methioninase combined with palbociclib regresses a doxorubicin-resistant dedifferentiated liposarcoma.

Liposarcoma is the most common type of soft tissue sarcoma. Among the subtypes of liposarcoma, dedifferentiated liposarcoma (DDLPS) is recalcitrant and has the lowest survival rate. The aim of the present study is to determine the efficacy of metabolic targeting with recombinant methioninase (rMETase) combined with palbociclib (PAL) against a doxorubicin (DOX)-resistant DDLPS in a patient-derived orthotopic xenograft (PDOX) model. A resected tumor from a patient with recurrent high-grade DDLPS in the right retroperitoneum was grown orthotopically in the right retroperitoneum of nude mice to establish a PDOX model. The PDOX models were randomized into the following groups when tumor volume reached 100 mm3: G1, control without treatment; G2, DOX; G3, PAL; G4, recombinant methioninase (rMETase); G5, PAL combined with rMETase. Tumor length and width were measured both pre- and post-treatment. On day 14 after initiation, all treatments significantly inhibited tumor growth compared to the untreated control except DOX. PAL combined with rMETase was significantly more effective than both DOX, rMETase alone, and PAL alone. Combining PAL and rMETase significantly regressed tumor volume on day 14 after initiation of treatment and was the only treatment to do so. The relative body weight on day 14 compared with day 0 did not significantly differ between each treatment group. The results of the present study indicate the powerful combination of rMETase and PAL should be tested clinically against DDLPS in the near future.

A combination of irinotecan/cisplatinum and irinotecan/temozolomide or tumor-targeting Salmonella typhimurium A1-R arrest doxorubicin- and temozolomide-resistant myxofibrosarcoma in a PDOX mouse model.

Myxofibrosarcoma (MFS) is the most common sarcomas in elderly patients and is either chemo-resistant or recurs with metastasis after chemotherapy. This recalcitrant cancer in need of improved treatment. We have established a patient-derived orthotopic xenograft (PDOX) of MFS. The MFS PDOX model was established in the biceps femoris of nude mice and randomized into 7 groups of 7 mice each: control; doxorubicin (DOX); pazopanib (PAZ); temozolomide (TEM); Irinotecan (IRN); IRN combined with TEM; IRN combined with cisplatinum (CDDP) and Salmonella typhimurium A1-R (S. typhimurium A1-R). Treatment was evaluated by relative tumor volume and relative body weight. The MFS PDOX models were DOX, PAZ, and TEM resistant. IRN combined with TEM and IRN combined with CDDP were most effective on the MFS PDOX. S. typhimurium A1-R arrested the MFS PDOX tumor. There was no significant body weight loss in any group. The present study suggests that the combination of IRN with either TEM or CDDP, and S. typhimurium have clinical potential for MFS.

Trabectedin arrests a doxorubicin-resistant PDGFRA-activated liposarcoma patient-derived orthotopic xenograft (PDOX) nude mouse model.

BACKGROUND: Pleomorphic liposarcoma (PLPS) is a rare, heterogeneous and an aggressive variant of liposarcoma. Therefore, individualized therapy is urgently needed. Our recent reports suggest that trabectedin (TRAB) is effective against several patient-derived orthotopic xenograft (PDOX) mouse models. Here, we compared the efficacy of first-line therapy, doxorubicin (DOX), and TRAB in a platelet-derived growth factor receptor-α (PDGFRA)-amplified PLPS. METHODS: We used a fresh sample of PLPS tumor derived from a 68-year-old male patient diagnosed with a recurrent PLPS. Subcutaneous implantation of tumor tissue was performed in a nude mouse. After three weeks of implantation, tumor tissues were isolated and cut into small pieces. To match the patient a PDGFRA-amplified PLPS PDOX was created in the biceps femoris of nude mice. Mice were randomized into three groups: Group 1 (G1), control (untreated); Group 2 (G2), DOX-treated; Group 3 (G3), TRAB-treated. Measurement was done twice a week for tumor width, length, and mouse body weight. RESULTS: The PLPS PDOX showed resistance towards DOX. However, TRAB could arrest the PLPS (p < 0.05 compared to control; p < 0.05 compared to DOX) without any significant changes in body-weight. CONCLUSIONS: The data presented here suggest that for the individual patient the PLPS PDOX model could specifically distinguish both effective and ineffective drugs. This is especially crucial for PLPS because effective first-line therapy is harder to establish if it is not individualized.

Combining Tumor-Selective Bacterial Therapy with Salmonella typhimurium A1-R and Cancer Metabolism Targeting with Oral Recombinant Methioninase Regressed an Ewing's Sarcoma in a Patient-Derived Orthotopic Xenograft Model.

BACKGROUND: Ewing's sarcoma (ES) is a recalcitrant disease in need of transformative therapeutics. OBJECTIVES: The aim of this study was to investigate the efficacy of tumor-selective Salmonella typhimurium A1-R combined with tumor metabolism targeting with oral administration of recombinant methioninase (o-rMETase), on an ES patient-derived orthotopic xenograft (PDOX) model. METHODS: The ES PDOX models were previously established in the right chest wall. The ES PDOX models were randomized into 5 groups when the tumor volume reached 80 mm3: G1: untreated control; G2: doxorubicin; G3: S. typhimurium A1-R; G4: o-rMETase; G5: S. typhimurium A1-R combined with o-rMETase. All mice were sacrificed on day 15. Body weight and tumor volume were assessed twice a week. RESULTS: S. typhimurium A1-R and o-rMETase respectively suppressed tumor growth as monotherapies (p = 0.050 and p = 0.032). S. typhimurium A1-R combined with o-rMETase regressed tumor growth significantly compared to untreated group on day 15 (p < 0.032). S. typhimurium A1-R combined with o-rMETase group was significantly more effective than S. typhimurium A1-R or o-rMETase monotherapy (p = 0.032, p = 0.032). CONCLUSIONS: The present results suggest that the combination of S. typhimurium A1-R and o-rMETase has promise to be a transformative therapy for ES.

High Efficacy of Pazopanib on an Undifferentiated Spindle-Cell Sarcoma Resistant to First-Line Therapy Is Identified With a Patient-Derived Orthotopic Xenograft (PDOX) Nude Mouse Model.

Undifferentiated spindle-cell sarcoma (USCS) is a recalcitrant -cancer. Our laboratory pioneered the patient-derived orthotopic xenograft (PDOX) nude mouse model with the technique of surgical orthotopic implantation (SOI). In the present study, we evaluated the efficacy of standard first-line chemistry of doxorubicin (DOX), gemcitabine (GEM) combined with docetaxel (DOC), compared to pazopanib (PAZ), a multi-targeting tyrosine-kinase inhibitor, in an USCS PDOX model. A high-grade USCS from a striated muscle of the patients was grown orthotopically in the right biceps femoris muscle of nude mice to establish the PDOX model. The PDOX models were randomized into the following groups when tumor volume reached 100 mm3 : G1, control without treatment; G2, DOX (3 mg/kg, intraperitoneal (i.p.) injection, weekly, for 2 weeks); G3, GEM (100 mg/kg, i.p., weekly, for 2 weeks) combined with DOC (20 mg/kg, i.p., once); G4, PAZ (100 mg/kg, p.o., daily, for 14 days). All treatments except DOX significantly inhibited tumor growth compared to untreated control on day 14 after treatment initiation. Tumor sizes were as fallows: control (G1): 332.0 ± 58.7 mm3 ; DOX (G2): 316.9 ± 55.9 mm3 , P = 0.605; GEM + DOC (G3): 228.9 ± 39.8 mm3 , P = 0.001; PAZ (G4): 173.8 ± 23.3 mm3 , P < 0.0001. PAZ showed significantly more efficacy compared to other therapies evaluated: DOX (P < 0.0001), GEM + DOC (P = 0.006). There were no animal deaths in any group and body weight of treated mice was not significantly different in each group. The present results demonstrate that the PDOX model of USCS can identify a promising novel agent with significantly greater efficacy than first-line therapy for this recalcitrant disease. J. Cell. Biochem. 118: 2739-2743, 2017. © 2017 Wiley Periodicals, Inc.

A Phase Ib/II Study of Gemcitabine and Docetaxel in Combination With Pazopanib for the Neoadjuvant Treatment of Soft Tissue Sarcomas.

LESSONS LEARNED: Our results highlight some of the challenges in the management of soft tissue sarcomas, which requires close cooperation between surgeons and medical oncologists and a careful selection of patients. The incidence of hepatotoxicity was a concerning finding and had been previously reported in patients treated with pazopanib.Although pharmacokinetic analysis was not part of this study, concomitant treatment with pazopanib has been recently reported to increase docetaxel exposure, which may explain the increased toxicity of combination regimens. It remains possible that lower doses of combined gemcitabine, docetaxel, and pazopanib may be tolerable. However, caution should be exercised in future trials investigating similar combinations. BACKGROUND: For extremity soft tissue sarcomas (STS), surgical resection remains the standard of care, and the addition of chemotherapy is controversial. This was a phase Ib/II trial of neoadjuvant therapy for patients with STS. METHODS: Patients with high grade, extremity STS of >8 cm and amenable to definitive resection were treated with up to four 21-day cycles of 900 mg/m(2) gemcitabine on days 1 and 8, 75 mg/m(2) docetaxel on day 8, and 400 mg of pazopanib daily (GDP), followed by surgery and, if indicated, radiation therapy. Primary and secondary endpoints (phase Ib portion) were the safety and rate of pathologic response. RESULTS: The trial was discontinued because of slow accrual after inclusion of five patients (leiomyosarcoma: two; undifferentiated pleomorphic sarcoma: three). Two patients completed four treatment cycles: one underwent surgery and one had insufficient response and received additional therapies. Three patients discontinued treatment because of toxicity. Grade 3 adverse events included hypertension, fatigue, aspartate aminotransferase (AST) or alanine aminotransferase (ALT) elevation, hoarseness, and myelotoxicity. There were no complete or partial responses. One patient had ≥ 90% pathologic response. Among four patients who underwent resection, three remain free of disease, and one patient eventually relapsed. CONCLUSION: GDP combination used in the neoadjuvant setting resulted in significant toxicity; despite pathologic responses, no objective responses occurred.