Sunitinib and Radiation in Patients With Resectable Soft-tissue Sarcoma

The presence of hypoxia has been documented in soft-tissue sarcomas, where it may contribute to radioresistance. Combinations of radiosensitisers such as ifosfamide and doxorubicin with radiotherapy have demonstrated promise in sarcomas, but with significant toxicity.

The rationale for this study is based on:

• the frequency of hypoxia in soft-tissue sarcomas
• the importance of radiotherapy in neoadjuvant treatment of soft-tissue sarcomas
• targeting hypoxic vasculature with sunitinib
• the single agent activity of sunitinib in soft-tissue sarcomas. This study will assess the feasibility and tolerability of the combination of sunitinib with standard preoperative radiotherapy. The surrogate endpoints of tumor necrosis and functional and RECIST imaging response will provide early evidence of response rate. Toxicities will be assessed both during chemoradiation and following surgery. The impact of treatment on the hypoxic component of the tumor will be investigated with F18 azamycin arabinoside PET scans.

Because the combination of sunitinib and radiotherapy has not been studied before, we propose a phase Ib design with dose reductions in the event of excessive toxicity. Sunitinib treatment will precede the commencement of radiotherapy by 2 weeks because there is preclinical evidence that priming the tumor vasculature may increase synergy with radiotherapy, and because sunitinib may have single agent activity in sarcomas, including measurable effects on tumor vasculature. Because it is anticipated that the likelihood of complications attributable to the combination of sunitinib and radiotherapy will be small, the starting dose of sunitinib will be 50mg/day for the two week lead-in period and then 25mg for 5 weeks with concurrent radiotherapy.

• Drug: Sunitinib malate
  Sunitinib dose 50 mg/day orally for 2 weeks prior to radiotherapy. Treatment Dose Levels during radiotherapy: Dose level 0: Sunitinib 50mg/day for 2 weeks prior to radiotherapy, followed by 25mg/day given concurrently with radiotherapy; Dose level 1: Sunitinib 50mg/day for 2 weeks prior to radiotherapy, followed by 37.5mg/day given concurrently with radiotherapy; Dose level -1: Sunitinib 37.5mg/day for 2 weeks prior to radiotherapy, followed by 37.5mg/day given concurrently with radiotherapy. Dose escalation/de-escalation: first 6 patients will be accrued at dose level 0. The dose levels at which subsequent patients will be accrued will be determined using a dose modification schedule.
  Other Name: Sutent
• Radiation: Radiotherapy
  Preoperative radiotherapy consisting of external beam radiotherapy at a dose of 50.4 Gy given in 28 fractions, five days a week, over five weeks and 3 days to the planning target volume.

Inclusion Criteria:

• Histologically confirmed soft-tissue sarcoma suitable for neoadjuvant radiotherapy and surgery
• minimum age 16 years
• ECOG performance status =1
• life expectancy of greater than 6 months
• patients must have normal organ and marrow function
• no evidence of a bleeding or thrombotic tendency, and no evidence of arterial or venous thrombosis
• not pregnant or breastfeeding
• the ability to give written informed consent.

Exclusion Criteria:

• Soft-tissue sarcoma located in sites where radiotherapy is associated with significant exposure of abdominal viscera
• patients with other invasive malignancies, with the exception of non-melanoma skin cancer, in the last 5 years
• patients receiving any other therapeutic investigational agents
• patients who are receiving concurrent treatment with any other anti-cancer therapy
• evidence of distant metastases
• uncontrolled intercurrent illness
• patients who are pregnant or breast feeding.

• Peter MacCallum Cancer Centre, Australia
• Pfizer