Young cancer patients who could not get a key medicine because of a national drug shortage were more likely to suffer a relapse than others who were able to get the preferred treatment, doctors report. It's the first evidence that a long-standing drug-supply problem probably has affected cancer treatment results in specific patients.
The study involved more than 200 children and young adults with a blood cancer called Hodgkin lymphoma. Like childhood leukemia, it can be cured nearly 80 percent of the time. But a drug shortage that has worsened since 2009 is threatening that success rate, doctors report in Thursday's New England Journal of Medicine.
Hundreds of drugs, including sedatives, antibiotics, painkillers, and cancer treatments, have gone in and out of short supply in recent years. Reasons include manufacturing and contamination problems, plant shutdowns, and fewer makers and lower profits for certain drugs, especially generics infused during surgery or cancer treatment.
Doctors sometimes substitute different drugs for ones in short supply. But proving that the swaps led to poorer results has been tough, especially for cancer patients whose disease and response to treatment vary so much.
"We really couldn't put our finger on, did anybody really suffer?" said Michael Link, a cancer specialist at Stanford University and past president of the American Society of Clinical Oncology.
The new study, led by Monika Metzger of St. Jude Children's Research Hospital in Memphis, gives the best evidence so far that patients are suffering. It focused on mechlorethamine, or nitrogen mustard, a drug that has been in short supply until last month, when more became available.
Doctors compared results among 181 Hodgkin lymphoma patients who received the drug with 40 others who were given a different chemotherapy, cyclophosphamide, when the first choice was unavailable. Only 75 percent of those given the substitute drug stayed free of cancer for two years vs. 88 percent who received the preferred treatment.
"We can think of no credible explanation for this dramatic difference" other than the drug substitution, the authors wrote.
No patients died, but those who relapsed were given more aggressive treatments, including stem-cell transplants that have more side effects and can harm fertility.