Background: Clarithromycin displays immunomodulatory and antineoplastic properties. As single agent, this macrolide is associated with tumor responses in anecdotal cases of relapsed/refractory extranodal marginal zone lymphoma (rrEMZL), with a putative dose-dependent effect. Tolerability and activity of high-dose clarithromycin (HD-K) in patients with rrEMZL were addressed in a phase II trial (clinicaltrials.gov NCT01516606).
Methods: HIV-negative adults with rrEMZL and at least one measurable/parametrable lesion were enrolled and treated with four courses of oral clarithromycin 2 g/day, days 1-14, every 21 days. Activity (overall response rate, ORR) was the primary end point.
Results: Twenty-three patients were registered (median age 70 years, range 47-88 years; M:F ratio: 0.27). HD-K was given at greater than or equal to second relapse in 11 patients. Ocular adnexae were the most commonly involved organs. Five patients had hepatitis B virus/hepatitis C virus (HBV/HCV) infections; Helicobacter pylori and Chlamydophila psittaci infections were excluded at the time of patient registration.Tolerability was excellent, even among HBV/HCV-positive patients; only two patients had grade >2 toxicity (nausea). Six patients achieved a complete remission and six a partial response (ORR = 52%; 95% confidence interval 32% to 72%). Age, previous treatment and stage did not influence activity. At a median follow-up of 24 (16-33) months, only two patients with responsive disease experienced relapse, with a 2-year progression-free survival of 56 ± 10%; all patients are alive.
Conclusions: HD-K is a safe and active salvage treatment in EMZL patients. This macrolide deserves to be further investigated in EMZL and other lymphoma categories.
Keywords: MALT lymphoma; clarithromycin; extranodal marginal zone lymphoma; macrolides.
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