• Safety and Tolerability of cG250 and sunitinib in patients with advanced RCC: Adverse events of cG250 administered concurrently with sunitinib [ Time Frame: 7 -13 weeks ] [ Designated as safety issue: Yes ]
  

• Tumour response assessed according to standard clinical criteria (RECIST) [ Time Frame: 7 - 13 weeks ] [ Designated as safety issue: No ]
  
• Presence of radioactivity in tumour and whole body, assessed by ¹²⁴I-cG250 PET imaging, serum levels of monoclonal antibody cG250 pharmacokinetics (¹²⁴I activity and ELISA) [ Time Frame: 7 weeks ] [ Designated as safety issue: No ]
  
• Serum HACA assayed by ELISA [ Time Frame: 7 - 13 weeks ] [ Designated as safety issue: Yes ]
  
• Tumour glycolytic metabolism and tumour blood flow assessment by serial [18]F-FDG and [15]O-H₂O PET scans [ Time Frame: 7 weeks ] [ Designated as safety issue: No ]
  

This study explores the safety, efficacy and effects on functional imaging of the combination of cG250 and sunitinib in patients with advanced renal cell carcinoma (kidney cancer).

When kidney cancer has spread beyond the kidney it is usually not possible to cure it with surgery. Other treatments such as radiotherapy or chemotherapy are also of limited value. Kidney cancers often rely on certain proteins for their growth, particularly proteins that affect the ways that blood vessels grow into the cancer. Ingrowth of blood vessels supplies cancer cells with oxygen and nutrition; without the blood vessels, cancer deposits can not grow in size. When growth of the blood vessels is blocked, established cancers may stop growing or may shrink. This has been shown to work for some drugs that target this process in kidney cancers. One of these drugs is called sunitinib.

A protein, called G250, is also thought to be important in helping kidney cancers to grow. G250 is found on the cell surface of many kidney cancers. One possible method of interfering with the function of G250 is to target G250 with an antibody known as cG250. Clinical trials with cG250 and have shown it to be safe, to home in on kidney cancer cells, and to persist in the blood and the cancer tissue for a long period of time.

The main purpose of this study is to explore whether the combination of sunitinib and cG250 is safe in patients with advanced kidney cancer. The study will also assess whether this combination is able to cause kidney cancer to shrink; will determine where cG250 travels within the body, whether the immune system reacts to the cG250 and whether sunitinib affects that; and whether the combination affects how kidney cancers grow or how blood flows within the tumour.

Patients with advanced kidney cancer who have never previously received cG250, sunitinib (or similar drugs) may be eligible to participate in the study. A total of 14 patients are expected to be recruited.

Eligible patients will receive cG250 10 mg/m² by weekly intravenous infusion for five weeks, followed by a two-week break (one cycle). The first and fifth dose will be trace-labeled with a radioactive substance (¹²⁴I-cG250) detectable by a special scan called a Positron Emission Tomography (PET scan) to allow studies of the distribution of cG250. Sunitinib 50 mg by daily oral dose will also be given for 4 weeks (commencing on day 8 of the first treatment cycle), followed by a two-week break. Up to two cycles of treatment will be given. If a second cycle is given, cG250 will be given as four weekly doses and daily sunitinib will start on the same day. No ¹²⁴I-cG250 will be administered after the first treatment cycle.

The extent of the kidney cancer will be assessed by CT scan at baseline and at the end of each treatment cycle. Safety assessments (physical examination, blood tests, gated cardiac blood pool scan, ECG-heart trace) will be performed at the beginning of each treatment cycle, repeated throughout the cycle and end of study. A number of blood tests and PET scans will be done in the first cycle to show how and in what amounts the ¹²⁴I-cG250 distributes in the body. Other PET scans ([18]F-FDG and [15]O-H₂O) will be performed to allow assessment of tumour growth and blood flow. Blood tests will also show whether the immune system recognises the infused cG250 by making an antibody against it.