The primary objective of this study is to allow rollover of the two remaining subjects from the other XL999 studies to continue to receive XL999.

The secondary objectives of this study are as follows:

• To evaluate tumor response after long term repeat administration of XL999 in two subjects rolled over from other XL999 studies.
• To characterize the long term safety and tolerability of XL999 after repeat administration in two subjects rolled over from other XL999 studies.
• To characterize the long term effects of XL999 on cardiac function after repeat administration in two subjects rolled over from other XL999 studies.

Inclusion Criteria:

• The subject is currently enrolled in Protocols XL999-001 or XL999-204
• The subject has received XL999 for at least one year prior to enrollment
• Per the respective parent XL999 protocol, the subject is eligible to continue to receive XL999 in the absence of progressive disease (PD) or unacceptable drug-related toxicity

Exclusion Criteria:

• Progressive disease
• Any development(s) that would meet the exclusion criteria from the subject's respective XL999 protocol (XL999-001 or XL999-204)