Response rates up to 50% have been observed in patients with relapsed CD20-positive non-Hodgkin’s lymphoma after treatment with the chimeric monoclonal anti-CD20 antibody rituximab(Drug information on rituximab) (Rituxan). The malignant cell population in lymphocyte-predominant Hodgkin’s disease (LPHD) also expresses the CD20 antigen in high density, while only 20% of all Hodgkin-Reed-Sternberg cells in classical Hodgkin’s disease (HD) are CD20 positive.
This phase II study investigates the safety and efficacy of 4 × 375 mg/m2 rituximab in patients with relapsed LPHD or CD20-positive classical HD. Eligibility criteria included expression of the CD20 antigen on more than 30% of all malignant cells; histologic slides had to be reviewed by a reference panel.
Six patients (five males, one female) have been treated so far (as of June 2000). Median age was 37 years (range: 26 to 52 years); median time since first diagnosis was 3 years (range: 1.7 to 5.9 years). All patients had at least one prior chemotherapy: all five patients with LPHD were in first relapse, while the HD patient had been treated with two previous therapeutic regimens, including autologous peripheral stem cell transplantation. With 375 mg/m2 rituximab weekly × 4 toxicity was moderate and transient. Side effects comprised chills, fever, and hypotension. At 5 months of median follow-up (range: 1 to 9 months), response rates were 100% (4 complete remissions, 1 partial remission) for patients with relapsed LPHD. The patient with the relapsed classical HD is in complete remission 10 months after completion of therapy.
CONCLUSION: Administration of rituximab to patients with LPHD or CD20-positive classical HD is safe and feasible. These preliminary data suggest high efficacy with response rates up to 100%. Longer follow-up is necessary. Because the number of patients with LPHD and CD20-positive classical HD is small, international cooperation has been started.