Phase I/II Study of Rituxan (R) in Combination with Doxil (D) in Patients (pts) with Relapsing or Refractory B-Cell Lymphoma: Promising Early Results.

In the past, the most common initial combination chemotherapy regimen used by most oncologists to treat B-cell lymphoma was the CHOP regimen. Although doxorubicin (DOX) is a major component of CHOP, it is associated with myelosuppression, alopecia, and potential cardiotoxicity. In vitro data has demonstrated synergistic activity between rituximab and certain drugs, including DOX. Because of D’s unique liposomal encapsulation, delivery, and toxicity profile, it may prove to be a more effective, less toxic anthracycline to combine with R. A formal Phase I/II trial to evaluate the safety and efficacy of R+D in pts with relapsing B-cell lymphoma was undertaken. R (375 mg/m²/dose) was given on day 1 and D (30 mg/m²/dose) on day 3 on q 21 day cycles for 6 cycles. Thirteen pts have completed therapy to date: 9F, 4M; Follicular lymphoma, grade 1 (n=6), grade 2 (n=1), grade 3 (n=3), DLBCL (n=3); med age = 63 (38–78); median number of prior Rx’s = 3 (range 1–8); prior anthracycline exposure (n=8). Overall, the combination of R + D was well-tolerated. Transient grade 3 cytopenias were noted in 3 pts with limited bone marrow reserve and grade 3 palmar/plantar erythrodysesthesia seen in 2 pts. All 13 pts completed the planned 6 courses of Rx. Objective responses were seen in 85% (11 of 13 pts), including 54% CR, 31% PR. Median time-to-progression has not been reached at 7+ months (range 4.5+ to 19+ months). No cardiac toxicity was seen and comparison of pre-Rx to post-Rx LVEF remained unchanged in 9, increased in 2, and decreased in 2 (yet still remaining > 50%). D + R immunochemotherapy is a well-tolerated, unique, non-cardiotoxic, and apparently effective salvage therapy for relapsed B-cell lymphoma. The study will continue until accrual of 42 pts has been reached.