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Sunitinib (Sutent) Basics for GIST

This page includes answers to the following questions. Click a question to jump to the corresponding section.

What is sunitinib (Sutent)?
Which GIST patients take sunitinib (Sutent)?
How does sunitinib (Sutent) work?
How should I take my sunitinib (Sutent)?
What is the typical dose and schedule for sunitinib (Sutent)?
What drug interactions occur with sunitinib (Sutent)?
Where can I see more information about sunitinib (Sutent) for GIST?
Can I get financial assistance for my sunitinib (Sutent) prescription?

What is sunitinib (Sutent)?

Sunitinib (Sutent) is a tyrosine kinase inhibitor that has anti-cancer and anti-angiogenesis effects. It was previously known as SU-11248, and its chemical name is sunitinib malate.  Pfizer is the manufacturer of sunitiniib.

Sutent was approved by the FDA for imatinib-resistant and imatinib-intolerant GIST and for renal cell carcinoma (kidney cancer) on January 26, 2006. This approval means that in the USA and other countries where sunitinib is approved, patients can get a prescription for sunitinib from their physicians.  Here is the link to the FDA approval notice.

Patients in countries where sunitinib (Sutent) has not yet been approved can obtain access to the drug through a clinical trial process.  Access this trial link and look for a site in the country of interest to you.  You may also call the international phone number for the Emerging Med trial matching service at  646-277-4065. 

There is a patient information sheet at the FDA site.  Full prescribing information, including clinical trial information, safety, dosing, drug-drug interactions and contraindications, is available at this FDA link

Pfizer provides information about sunitinib at www.sutent.com

Which GIST patients take sunitinib (Sutent)?

Sunitinib is "second-line" therapy for gastrointestinal stromal tumor (GIST cancer).  GIST patients may use sunitinib if they:

  • show primary resistance to imatinib (lack of response, GIST not controlled)
  • show secondary resistance to imatinib (after initial control at the start of imatinib therapy, one or more tumors begin growing again) 
  • are intolerant of imatinib (cannot take it due to severe side effects).
     

How does sunitinib (Sutent) work?

Sunitinib malate (Sutent) is a multi-targeted tyrosine kinase inhibitor that inhibits these cell-surface receptors: KIT, PDGFRA and PDGFRB, FLT3, CSF-1R, and all three VEGF receptors.  Its anti-tumor effects against gastrointestinal stromal tumor (GIST cancer) occur primarily through inhibition of KIT and PDGFRA, receptors for the growth factors stem cell factor and platelet derived growth factor.  Although anti-angiogenesis action of sunitinib could occur through inhibition of VEGF receptors, this mode of action does not appear to be prominent in GIST.

How should I take my sunitinib (Sutent)?

Sunitinib (Sutent) is an oral drug in capsule form, usually taken once per day. It comes in capsules of 12.5 mg, 25 mg, and 50 mg.  It may be taken with or without food, at any time of day that you find convenient to establish as a routine (same time each day).  Avoid grapefruit and grapefruit juice when taking sunitinib, as these substances increase the blood levels of the medication by inhibiting the liver enzyme CYP3A4 that eliminates sunitinib from the body.

What is the typical dose and schedule for sunitinib (Sutent)?


 

The starting dose and schedule used in clinical trials of sunitinib was 50 mg per day taken for 4 weeks, followed by a 2-week "washout" period during which the patients did not take sunitinib.  30-40% of patients required dose reductions on this schedule.

More recently a continuous-dosing (no washout period) schedule of 37.5 mg per day of sunitinib has been studied (George et al, 2008, George et al, 2009 ).  Results appear comparable to the higher-dose regimen, and side effects are reduced.

You can discuss your starting dose with your oncologist.  If your oncologist wants you to take a 50-mg dose, it may be desirable to begin at a lower dose and increase it gradually in order to let your body accommodate to the drug more easily.

Some patients who are unable to tolerate one certain dose every day have developed alternating schedules under the supervision of their oncologists, such as alternation between 50 mg one day and 37.5 mg the next day, or 37.5 mg and 25 mg.

What drug interactions occur with sunitinib (Sutent)?

Sunitinib, like imatinib, is primarily metabolized by liver enzyme CYP3A4.  Therefore, any drugs or foods that increase the production of CYP3A4 (CYP3A4 inducers) will enable the body to eliminate sunitinib more quickly, reducing your effective dose of the drug.  In contrast, any drugs or foods that decrease CYP3A4 (CYP3A4 inhibitors) will increase your exposure to sunitinib.  The following drugs and substances of concern are named in the Sutent prescribing information and/or the NCCN Task Force Report: Optimal Management of Patients with GIST -- Update of the NCCN Clinical Practice Guidelines:

CYP3A4 Inducers to avoid or requiring dosage increases of sunitinib:
dexamethasone, phenytoin, carbamazepine, rifampin, rifabutin, rifapentin, phenobarbital, St. John’s Wort

CYP3A4 Inhibitors to avoid or requiring dosage decreases of sunitinib:
Aprepitant, ketoconazole, itraconazole, clarithromycin, Erythromycin, atazanavir, indinavir, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, voriconazole

For a free-access medical paper with tables detailing many different drug interactions with imatinib and sunitinib, see the following (click title to link to the free paper):
Haouala A, Widmer N, Duchosal MA, Montemurro M, Buclin T, Decosterd LA.
Drug interactions with the tyrosine kinase inhibitors imatinib, dasatinib, and nilotinib.
Blood. 2011 Feb 24;117(8):e75-87. PubMed PMID: 20810928.

 

Where can I see more information about sunitinib (Sutent) for GIST?

Pfizer, the manufacturer of sunitinib, maintains several informative websites:
a patient education website at http://www.sutent.com
a health care professional website at this link

Can I get financial assistance for my sunitinib (Sutent) prescription?

Pfizer provides financial assistance through its First Resource website or phone (877) 744-5675.  Patients can also access numerous other sources of prescription assistance listed on our links page.

 

 

 

 



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