Final Results of a Multicenter Phase II Trial with Translational Elements to Investigate the Possible Infective Causes of Ocular Adnexal Marginal Zone B-Cell Lymphoma (OAMZL) with Particular Reference to Chlamydia Species and the Efficacy of Doxycycline As First-Line Lymphoma Treatment (the IELSG#27 TRIAL)

Chlamydophila psittaci (Cp) infection carries a potential pathogenic role in OAMZL and has been detected in tumor tissue of a high proportion of patients (pts), with geographic differences in its prevalence rates. The use of immunohistochemistry, immunofluorescence and electronic microscopy techniques has identified monocyte/macrophage as carriers of Cp in OAMZL, and bacteria eradication with doxycycline (DOXY) has been associated with lymphoma regression in half of pts. Notwithstanding these achievements, clinical and therapeutic knowledge on this association mainly result from retrospective studies or trials including also patients with relapsed disease after wide-ranging follow-up. Prospective studies focusing exclusively on pts with newly diagnosed OAMZL do not exist. Herein, we report the final results of the first international prospective phase II trial aimed to investigate Cp prevalence and DOXY efficacy as first-line therapy in pts with newly diagnosed OAMZL (ClinicalTrial.gov NCT01010295).

To elucidate prevalence of Chlamydiae infections, and to evaluate the efficacy of DOXY both in terms of bacterial eradication and as upfront anti-lymphoma therapy in pts with newly diagnosed OAMZL.

This trial included two different parts, named A and B. The part A included pts with newly diagnosed stage-IEA OAMZL and measurable/parametrable disease; these pts were assessed for chlamydial infection and were treated with DOXY 100 mg orally twice daily for 21 days. The part B included pts with lymphoma categories other than MZL, non neoplastic lesions of the ocular adnexae or OAMZL not eligible for part A; these pts were treated following local guidelines.

Chlamydial infections were assessed on diagnostic tumor samples, conjunctival swabs and peripheral blood mononuclear cells (PBMC) from A and B pts by three different PCR protocols targeting 16rRNS and intergenic spacer 16S–23S, ompA and hsp60, respectively. Bacterial eradication was tested on conjunctival swabs and PBMC collected at basal time, at 3 and 12 months after DOXY (only part A pts). Clinical and ophthalmologic examination and MRI imaging were performed at the same timepoints, and every six months during follow-up.

From August 2006 to November 2010, 54 pts from 6 centers were enrolled; 34 pts with OAMZL entered the part A, while 13 pts with non-parametrable OAMZL and 7 pts with other lymphoproliferative disorders entered the part B. Diagnostic material was available for molecular analysis in 44 cases; Cp was detected in biopsies of 32/37 OAMZL (86%) and in 4/7 non-MZL. All cases were negative for C. pneumoniae and C. trachomatis. Among 36 Cp+ pts, infection was detected in 100% of swabs and in 75% of PBMC; swabs or PBMCs from pts with Cp-negative OAMZL were invariably negative.

All pts completed the planned DOXY treatment; no relevant toxicity was reported. Among 34 pts entering the part A, 28 were evaluable for bacteria eradication (Cp detected in swabs in 8 pts, in PBMC in one, in both samples in 19). At 3 months from DOXY, Cp was not detected in swabs and PBMC of 14 evaluable pts, with an eradication rate of 50%; at one year of follow-up, Cp was still detected in three of these apparently eradicated pts.

Lymphoma regression after DOXY treatment (part A) was complete in six pts (18%; 95%CI: 5–31%), and partial in 16 (ORR= 65%, 95%CI: 49–81%); 11 had SD and one PD. At a median follow-up of 27 months (range 3–51), 13 pts experienced relapse, with a 2-year PFS of 55±9%. A trend to a higher response rate (82% vs. 53%; p=0.12) and 3-yr PFS (72% vs. 52%; p=0.14) was observed in eradicated pts. No significant association between site of presentation (conjunctiva vs. orbit) and clinical outcome was detected. There was no association between animal exposure and bacteria eradication or lymphoma response. All patients but two (stroke and myocardial infarction) are alive, with a 3-yr OS of 92%.

Cp infection is frequent in newly diagnosed OAMZL, and could be also present in other lymphoproliferative disorders of the ocular adnexae. First-line DOXY is an active, safe and rational strategy in pts with limited-stage OAMZL, with lymphoma regression in 65% of cases. However, DOXY failed to eradicate Cp infection in half of pts, with a negative impact on outcome. Further investigations aimed to identify additional potential infective agents associated with OAMZL and more active antibiotic regimens are warranted.

Montalban:Red Temática de Investigación Cooperativa en Cancer (RETICC): Research Funding; Asociación Española contra el Cancer: Research Funding.