SAN DIEGO – The median survival for patients with tumor stage mycosis fungoides who received oral bexarotene therapy was 3.3 years, compared with a median of 7.7 years for patients who did not receive the drug, results from a long-term, single-center study demonstrated.
The finding "was not intuitive, because approximately 54% of patients who took bexarotene responded to the drug, but it had a negative impact on survival," Dr. John A. Zic said in an interview following a poster session at the annual meeting of the American Academy of Dermatology, where the study was presented.
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Dr. John A. Zic
Mycosis fungoides accounts for the majority of cutaneous T-cell lymphoma cases, yet no randomized controlled trials exist to compare existing therapies head to head. "Therefore, it is important to gather long-term clinical data for retrospective analysis when these patient cohorts exist to analyze how different therapies contribute to patient outcome," Dr. Zic and his associates wrote in their poster abstract.
For the current study, the researchers reviewed data from 39 patients with tumor stage mycosis fungoides who were followed at the Vanderbilt University Cutaneous Lymphoma Clinic in Nashville, Tenn., between July of 1995 and July of 2010. They set out to determine if patients who received therapy with oral bexarotene for the treatment of tumor stage mycosis fungoides had improved outcome, compared with those who did not take the drug. Bexarotene is a synthetic retinoid approved by the Food and Drug Administration in 1999 for the treatment of refractory, advanced-stage cutaneous T-cell lymphoma, including mycosis fungoides.
Of the 39 patients 27 (69%) were male. More than half of patients (67%) received oral bexarotene while 33% did not. Patients in the bexarotene group were older than those who did not receive the drug (a mean of 61 vs. 56 years, respectively), and a higher proportion had late clinical stage disease at diagnosis (19 patients vs. 10 patinets). They were also more likely to have large cell transformation, "which is a negative prognostic indicator," said Dr. Zic, associate professor of dermatology at Vanderbilt University.
He went on to report that 54% of patients in the bexarotene group achieved durable response, which was defined as a greater than 50% clearing for at least 1 month. However, the median overall survival for patients in the bexarotene group was 3.3 years, compared with 7.7 years for patients who did not receive the drug.
The researchers also found that patients who were diagnosed with mycosis fungoides before the year 2000 "seemed to have a longer survival than patients who were diagnosed after 2000," Dr. Zic said. "You would think that with the introduction of newer therapies we might be able to impact survival in the past decade versus survival two decades ago. We didn’t find that, and we’re not sure why. However, the more recently enrolled patients appear to be sicker; they have higher stages of disease and more [large cell] transformation. That might explain the difference."
Dr. Zic acknowledged that a chief limitation of the study was its retrospective design. "There could be certain biases introduced such as selection bias and referral bias that might help to explain some of the differences that were seen," he said.
Further analyses of the patients are planned.
Dr. Zic said that he had no relevant financial disclosures.