Posted by July 29th, 2011
Frequently Asked Questions
What drugs for colorectal cancer patients are in short supply?
The list of drugs on the short supply list can change week to week, but there are two drugs that have been low for some time: leucovorin and fluorouracil (5-FU).
Leucovorin is a folic acid that has long been used with 5-FU to treat colorectal and other cancers. Leucovorin boosts the effectiveness of 5-FU, by lengthening the time that the very short-acting 5-FU works to kill cancer cells.
Why are there leucovorin and 5-FU shortages?
For several years, manufacturing problems at the US companies that make and distribute generic leucovorin and 5-FU and have limited the amount of the drug that they are able to ship to pharmacies and doctors. Many oncologists now cannot obtain it at all. Others can only get limited supplies, so they are reducing doses for patients. Additionally, one of the companies that makes 5-FU has blamed their shortage on manufacturing delays.
Both the FDA and the American Society of Health-System Pharmacists track drug shortages, the reasons for those shortages, and when the shortage for each drug might be resolved. But the national picture does not always reflect day-to-day shortages in specific parts of the country or individual cancer centers.
What choices do I have if my doctor doesn’t have leucovorin?
The National Comprehensive Cancer Network (NCCN), which provides cancer treatment guidelines, has recommended that doctors do one of the following:
- Use a lower dose of leucovorin for all patients. (Several studies have shown equivalent effectiveness at lower doses.)
- Use Fusilev® (levoleucovorin) a brand-name drug with a chemical structure similar to leucovorin. Although the dosage is different, levoleucovorin has the same effectiveness as leucovorin when combined with 5-FU. It was approved by the FDA in April 2011 to treat advanced colorectal cancer.
- If there are no other options, “treatment without leucovorin would be reasonable.” For patients who can tolerate it without side effects, NCCN suggests increasing the bolus dose of 5-FU in the range of 10 percent.
The FDA has also approved temporarily importing injectable calcium folinate–the form of leucovorin most commonly used in Europe.
What choices do I have if my doctor doesn’t have 5-FU?
The Association of Health System Pharmacists recommends that doctors:
- Evaluate the health-care system’s total supply of fluorouracil before beginning patients on combination chemotherapy regimens containing fluorouracil. If adequate supplies are not available, select an alternative regimen.
- Consult a Hematology/Oncology specialist for patient- and neoplasm-specific recommendations.
- Refer to the ASHP Guidelines on Managing Drug Product Shortages for more guidance on developing a multidisciplinary plan when the supply must be allocated.
It is possible to use Xeloda® (capecitabine) in place of some 5-FU and leucovorin regimens, but there are important safety concerns to think about. Some research has found that an immediate switch from 5-FU to Xeloda may mean severe side effects.
A waiting period to allow folate build-up in cells may be necessary. Be sure your doctor is aware of this possibility.
What is Fight Colorectal Cancer doing to help patients, and to solve this problem?