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MedKoo CAT#: 205665

CAS#: 705946-27-6

Description: XL999, a Spectrum Selective Kinase Inhibitor(TM) (SSKIs), is a potent inhibitor of key RTKs implicated in the development and maintenance of tumor vasculature and in the proliferation of some tumor cells. It inhibits the FGFR, VEGFR and PDGFR RTKs and exhibited excellent activity in target-specific cellular functional assays. In addition, XL999 is a potent inhibitor of FLT3, an important driver of leukemia cell proliferation in some patients with acute myelogenous leukemia (AML). In several preclinical models of human tumors, including breast, lung, colon and prostate cancer, XL999 demonstrated potent inhibition of tumor growth, and also caused regression of large well-established tumors.

Price and Availability

Size Price Shipping out time Quantity
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Pricing updated 2020-09-23. Prices are subject to change without notice.

XL999 is not in stock, but may be available through custom synthesis. For cost-effective reason, minimum 1 gram order is requested. The product will be characterized by NMR, HPLC and MS analysis. Purity (HPLC) is usually >98%. CoA, QC data, MSDS will be provided when product is successfully made. The estimated lead time is 2-3 months. Please send email to sales@medkoo.com to inquire quote.

Chemical Structure


Theoretical Analysis

MedKoo Cat#: 205665
Name: XL999
CAS#: 705946-27-6
Chemical Formula: C26H28FN5O
Exact Mass: 445.2278
Molecular Weight: 445.5424
Elemental Analysis: C, 70.09; H, 6.33; F, 4.26; N, 15.72; O, 3.59

Synonym: XL999, XL-999, XL 999

IUPAC/Chemical Name: (Z)-5-((1-ethylpiperidin-4-yl)amino)-3-((3-fluorophenyl)(5-methyl-1H-imidazol-2-yl)methylene)indolin-2-one


InChi Code: InChI=1S/C26H28FN5O/c1-3-32-11-9-19(10-12-32)30-20-7-8-22-21(14-20)24(26(33)31-22)23(25-28-15-16(2)29-25)17-5-4-6-18(27)13-17/h4-8,13-15,19,30H,3,9-12H2,1-2H3,(H,28,29)(H,31,33)/b24-23-

SMILES Code: O=C1NC2=C(C=C(NC3CCN(CC)CC3)C=C2)/C1=C(C4=CC=CC(F)=C4)/C5=NC=C(C)N5

Technical Data

Solid powder

>98% (or refer to the Certificate of Analysis)

Shipping Condition:
Shipped under ambient temperature as non-hazardous chemical. This product is stable enough for a few weeks during ordinary shipping and time spent in Customs.

Storage Condition:
Dry, dark and at 0 - 4 C for short term (days to weeks) or -20 C for long term (months to years).

Soluble in DMSO, not in water

Shelf Life:
>5 years if stored properly

Drug Formulation:
This drug may be formulated in DMSO

Stock Solution Storage:
0 - 4 C for short term (days to weeks), or -20 C for long term (months).

HS Tariff Code:

Additional Information

XL999 is a potent spectrum-selective inhibitor of receptor tyrosine kinases including VEGFR2/KDR, FGFR1/3, PDGFR-ß, FLT3, RET, KIT, & SRC. A Ph 1 clinical study in pts w/advanced malignancies evaluating weight-based (0.2 - 6.4 mg/kg) & fixed dose (200 mg & 160 mg) XL999 administered by 4hr IV infusion on a wkly or every other wk schedule has shown preliminary evidence of anti-tumor activity (3 PRs & 10 pts w/SD lasting 3-26+ months). The safety profile was characterized by hypertension & cardiovascular changes including EKG, LVEF decrease &/or cardiac enzyme elevation following 1st dose administration. DLTs were cardiac failure & transaminase elevation. A dose of 2.4 mg/kg/wk was selected for phase II evaluation. (source : Journal of Clinical Oncology, 2007 ASCO Annual Meeting Proceedings Part I. Vol 25, No. 18S (June 20 Supplement), 2007: 18112 ).


 1: You WK, Sennino B, Williamson CW, Falcón B, Hashizume H, Yao LC, Aftab DT, McDonald DM. VEGF and c-Met blockade amplify angiogenesis inhibition in pancreatic islet cancer. Cancer Res. 2011 Jul 15;71(14):4758-68. doi: 10.1158/0008-5472.CAN-10-2527. Epub 2011 May 25. PubMed PMID: 21613405; PubMed Central PMCID: PMC3138890.

2: Bayes M. Gateways to clinical trials. Methods Find Exp Clin Pharmacol. 2007 Mar;29(2):153-73. PubMed PMID: 17440629.