Rituximab: enhancing outcome of autologous stem cell transplantation in non-Hodgkin's lymphoma

CD20-targeted T cells after stem cell transplantation for high risk and refractory non-Hodgkin's lymphoma

A phase I trial of infusing anti-CD3 × anti-CD20 bispecific antibody (CD20Bi) armed activated T cells (aATC) was conducted in high-risk/refractory non-Hodgkin's lymphoma patients to determine whether aATC infusions are safe, affect immune recovery, and induce an antilymphoma effect. Ex vivo expanded ATC from 12 patients were armed with anti-CD20 bispecific antibody, cryopreserved, and infused after autologous stem cell transplantation (SCT). Patients underwent SCT after high-dose chemotherapy, and aATC infusions were started on day +4. The patients received 1 infusion of aATC per week for 4 weeks after SCT with doses of 5, 10, 15, and 20 × 10(9). aATC infusions were safe and did not impair engraftment. The major side effects were chills, fever, hypotension, and fatigue. The mean number of IFN-γ Enzyme-linked Immunosorbent Spots (ElSpots) directed at CD20 positive lymphoma cells (DAUDI, P = .0098) and natural killer cell targets (K562, P < .0051) and the mean specific cytotoxicity directed at DAUDI (P = .037) and K562 (P = .002) from pre-SCT to post-SCT were significantly higher. The increase in IFN-γ EliSpots from pre-SCT to post-SCT in patients who received armed ATC after SCT were significantly higher than those in patients who received SCT alone (P = .02). Serum IL-7, IL-15, Macrophage inflammatory protein (MIP)-1 beta, IP-10, MIP-1α, and Monokine induced by gamma interferone increased within hours after infusion. Polyclonal and specific antibodies were near normal 3 months after SCT. aATC infusions were safe and increased innate and specific antilymphoma cell immunity without impairing antibody recovery after SCT.

Autografting followed by rituximab for chemosensitive mantle cell lymphoma: A pilot study and literature review

Mantle cell lymphoma (MCL) is rarely cured with either conventional-dose chemotherapy or autografting. Recent evidence suggests that anti-CD20 monoclonal antibody therapy (rituximab) in combination with chemotherapy may improve the response rate. We report a pilot study of autografting using busulfan-melphalan conditioning followed by rituximab in 9 patients (median age 52 years) with chemosensitive MCL. Rituximab was given for 4 doses of 375 mg/m(2) between 4 and 10 weeks post-transplant. Three of 5 patients autografted after induction therapy remain alive in clinical and molecular complete remission at 33-50 months post-transplant. Only 1 of 4 patients autografted after relapse remains in complete remission. Two of the 3 patients with persistent marrow molecular positivity post-autograft became negative after rituximab therapy. Molecular negativity was first observed in 2 patients only after rituximab therapy. Overall, 2 patients have relapsed and the remaining 3 died of late-onset respiratory failure, probably reflecting infection and/or aggressive conditioning in an older patient population. These preliminary results, together with a review of the literature, suggest that the combination of autografting and rituximab may lead to durable molecular remissions in patients with chemosensitive MCL. Further studies are required to clarify whether the administration of rituximab: (1) is optimal pre- or post-autograft and (2) impacts on the incidence of infection and idiopathic pneumonitis in this context.

Use of rituximab in diffuse large B-cell lymphoma in the salvage setting

The addition of rituximab (R) to CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy was a milestone in the development of front-line therapy for diffuse large B-cell lymphoma (DLBCL). R-CHOP and equivalent rituximab-containing anthracycline-based regimens are now widely accepted as the standard of care in this setting. However, the optimal treatment for patients with DLBCL relapsing or progressing after front-line therapy is not yet established. This review explores the role of rituximab in the treatment of DLBCL in the salvage setting, as monotherapy, in combination with chemotherapy or novel agents, and in the context of autologous stem cell transplantation (ASCT). Current evidence suggests that rituximab may improve outcomes in several ways: the higher response rates achieved with rituximab-based induction in the salvage setting optimize the number of patients who are able to proceed to high-dose therapy -ASCT; rituximab may improve outcomes following ASCT when used as post-transplantation consolidation/maintenance therapy; and addition of rituximab to salvage regimens may improve outcomes for patients ineligible for transplantation. However, patients refractory to or relapsing after first-line therapy (including rituximab-based regimens) still have a poor prognosis. In conclusion, rituximab in salvage therapy for DLBCL is effective and well tolerated. Ongoing studies will further clarify the optimal use of rituximab in the salvage setting.

Mobilization of peripheral blood progenitor cells after DHAP regimen with or without rituximab: a large multicenter comparative study in patients with malignant lymphoma

DHAP regimen is commonly used in patients with lymphoma. It is routinely used in combination with the monoclonal anti-CD20 antibody rituximab (R-DHAP), particularly for peripheral blood stem cell (PBSC) mobilization. The aim of this study was to assess the impact of rituximab on PBSC mobilization in patients with lymphoma receiving DHAP chemotherapy. We retrospectively reviewed the data of patients treated by DHAP or R-DHAP regimens as PBSC mobilization protocol between July 1998 and June 2005. Sixty-nine patients were included in the study: 21 in the DHAP group and 48 in the R-DHAP group. Both groups were not statistically different in term of clinical and biological presentation of the disease. The first cytapheresis was performed at day 10 in the R-DHAP group versus day 11 in the DHAP group. In contrast, the number of circulating CD34(+) cells was higher, but not significant, in the R-DHAP group than the DHAP group, namely 9.7x10(6) CD34(+) cells/kg and 6.1x10(6) CD34(+) cells/kg, respectively. Finally, the complete remission status at time of harvest was the only one factor associated with poor mobilization on multivariate analysis. In conclusion, our results show that rituximab does not impair PBSC collection.

Tolerability and safety of rituximab (MabThera)

Rituximab, a human/mouse chimeric anti-CD20 antibody, has become part of standard therapy for patients with CD20-expressing B-cell lymphoma, and is currently under investigation for other indications including autoimmune diseases, in particular rheumatoid arthritis (RA). Its characteristic tolerability profile was established soon after clinical testing began and compares favourably with chemotherapy. The majority of patients experience mild to moderate infusion-related reactions (IRRs) during the first administration of rituximab, but the incidence decreases markedly with subsequent infusions. Current data suggest that the type of adverse events in patients with RA are similar to those in lymphoma, but that adverse events related to the rituximab infusions are less severe and less frequent. Rituximab induces a rapid depletion of normal CD20-expressing B-cells in the peripheral blood, and levels remain low or undetectable for 2-6 months before returning to pretreatment levels, generally within 12 months. Serum immunoglobulin levels remain largely stable, although a reduction in IgM has been described. T-cells are unaffected by rituximab and consequently opportunistic infections rarely occur in association with rituximab therapy. When used in combination with a variety of chemotherapeutic regimens, rituximab does not add to the toxicity of chemotherapy, with the exception of a higher rate of neutropenia. However, this does not translate into a higher infection rate. Over 540,000 patients worldwide have now received rituximab and serious adverse reactions have occurred in a small minority of patients, but for the great majority of patients, rituximab is safe and well tolerated.

High-dose treosulfan in patients with relapsed or refractory high-grade lymphoma receiving tandem autologous blood stem cell transplantation

This phase I/II study evaluated high-dose treosulfan in patients with high-grade lymphoma. In all, 21 patients (median age 51, 25-60 years) with primary refractory disease (n=3) or early (n=11) or late (n=7) relapse received DexaBEAM and one course etoposide for cytoreduction and PBPC mobilization. Subsequently, 16 patients received 30 g/m2 treosulfan and 140 mg/m2 melphalan, followed by autologous transplantation. Nine patients received a 2nd high-dose treatment (HDT) with 30 g/m2 treosulfan and 750 mg/m2 thiotepa. Recovery time to >1/nl leukocytes and >25/nl thrombocytes was 8.9 (range 8-11) and 11.9 (8-16) days after 1st and 9.6 (7-13) and 13 (9-19) days after 2nd HDT. Reversible grade 3 or 4 nonhematologic toxicities included mucositis (n=7), infection (n=7) and one episode of re-entry tachycardia. Two treatment-related deaths occurred after 2nd HDT. Since three dose-limiting toxicities occurred among nine patients receiving tandem HDT, 30 g/m2 of treosulfan was considered MTD in this setting. Patients with late compared to early relapse or refractory disease had a higher probability of CR (6/7 vs 3/14 patients, P=0.017) and overall survival (71 vs 21%, P<0.05, 24-49 months follow-up). In conclusion, high-dose treosulfan as major therapy component induces sustained complete remissions in relapsed high-grade lymphoma with acceptable toxicity.

Clinical use of rituximab in haematological malignancies

Rituximab is a chimeric human/mouse monoclonal antibody that is approved for the treatment of relapsed and refractory non-Hodgkin's lymphoma (NHL) and in combination with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy as first-line therapy for diffuse large B-cell NHL, where it has shown the first survival advantage over CHOP alone in more than 20 years. Strategies to help define the optimal therapeutic usage of rituximab are being assessed, including first-line and maintenance or extended therapy, and the combination of rituximab with chemotherapy in indolent NHL. Emerging data suggest that earlier use may yield higher response rates, extended therapy can prolong remission, and the addition of rituximab to chemotherapy can increase clinical and molecular remission rates when compared with those achieved using chemotherapy alone. Studies in the peritransplant setting suggest a role for rituximab in vivo purging prior to transplant and/or maintenance rituximab as a means of clearing minimal residual disease. Rituximab has also shown activity in other B-cell disorders such as chronic lymphocytic leukaemia. The full potential of this immunotherapeutic agent remains to be defined in ongoing and future clinical trials.