Induction of anti-tumor activity following autologous stem cell transplantation: immunotherapeutic implications

Augmenting Autologous Stem Cell Transplantation to Improve Outcomes in Myeloma

Consolidation with high-dose chemotherapy and autologous stem cell transplantation (ASCT) is the standard of care for transplantation-eligible patients with multiple myeloma, based on randomized trials showing improved progression-free survival with autologous transplantation after combination chemotherapy induction. These trials were performed before novel agents were introduced; subsequently, combinations of immunomodulatory drugs and proteasome inhibitors as induction therapy have significantly improved rates and depth of response. Ongoing randomized trials are testing whether conventional autologous transplantation continues to improve responses after novel agent induction. Although these results are awaited, it is important to review strategies for improving outcomes after ASCT. Conditioning before ASCT with higher doses of melphalan and combinations of melphalan with other agents, including radiopharmaceuticals, has been explored. Tandem ASCT, consolidation, and maintenance therapy after ASCT have been investigated in phase III trials. Experimental cellular therapies using ex vivo-primed dendritic cells, ex vivo-expanded autologous lymphocytes, Killer Immunoglobulin Receptor (KIR)-mismatched allogeneic natural killer cells, and genetically modified T cells to augment ASCT are also in phase I trials. This review summarizes these strategies and highlights the importance of exploring strategies to augment ASCT, even in the era of novel agent induction.

High-dose therapy with autologous stem cell transplantation versus chemotherapy or immuno-chemotherapy for follicular lymphoma in adults

BACKGROUND

Follicular lymphoma (FL) is the most common indolent and second most common Non-Hodgkin`s lymphoma (NHL) in the Western world. Standard treatment usually includes rituximab and chemotherapy. High-dose therapy (HDT) followed by autologous stem cell transplantation (ASCT) is an option for patients in advanced stages or for second-line therapy, leading to improved progression-free survival (PFS) rates. However, the impact of HDT and ASCT remains unclear, as there are hints of an increased risk of second cancers.

OBJECTIVES

We performed a systematic review with meta-analysis of randomised controlled trials (RCTs) comparing HDT plus ASCT with chemotherapy or immuno-chemotherapy in patients with FL with respect to overall survival (OS), PFS, treatment-related mortality (TRM), adverse events and secondary malignancies.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and EMBASE as well as conference proceedings from January 1985 to September 2011 for RCTs. Two review authors independently screened search results.

SELECTION CRITERIA

Randomised controlled trials comparing chemotherapy or immuno-chemotherapy with HDT followed by ASCT in adults with previously untreated or relapsed FL.

DATA COLLECTION AND ANALYSIS

We used hazard ratios (HR) as effect measures used for OS and PFS as well as relative risks for response rates. Two review authors independently extracted data and assessed the quality of trials.

MAIN RESULTS

Our search strategies led to 3046 potentially relevant references. Of these, five RCTs involving 1093 patients were included; four trials in previously untreated patients and one trial in relapsed patients. Overall, the quality of the five trials is judged to be moderate. All trials were reported as randomised and judged to be open-label studies, because usually trials evaluating stem cell transplantation are not blinded. Due to the small number of studies in each analysis (four or less), the quantification of heterogeneity was not reliable and not evaluated in further detail. A potential source of bias are uncertainties in the HR calculation. For OS, the HR had to be calculated for three trials from survival curves, for PFS for two trials.We found a statistically significant increased PFS in previously untreated FL patients in the HDT + ASCT arm (HR = 0.42 (95% confidence interval (CI) 0.33 to 0.54; P < 0.00001). However, this effect is not transferred into a statistically significant OS advantage (HR = 0.97; 95% 0.76 to 1.24; P = 0.81). The subgroup of trials adding rituximab to both intervention arms (one trial) confirms these results and the trial had to be stopped early after an interim analysis due to a statistically significant PFS advantage in the HDT + ASCT arm (PFS: HR = 0.36; 95% CI 0.23 to 0.55; OS: HR = 0.88; 95% CI 0.40 to 1.92). In the four trials in previously untreated patients there are no statistically significant differences between HDT + ASCT and the control-arm in terms of TRM (RR = 1.28; 95% CI 0.25 to 6.61; P = 0.77), secondary acute myeloid leukaemia/myelodysplastic syndromes (RR = 2.87; 95% CI 0.7 to 11.75; P = 0.14) or solid cancers (RR = 1.20; 95% CI 0.25 to 5.77; P = 0.82). Adverse events were rarely reported and were observed more frequently in patients undergoing HDT + ASCT (mostly infections and haematological toxicity).For patients with relapsed FL, there is some evidence (one trial, N = 70) that HDT + ASCT is advantageous in terms of PFS and OS (PFS: HR = 0.30; 95% CI 0.15 to 0.61; OS: HR = 0.40; 95% CI 0.18 to 0.89). For this trial, no results were reported for TRM, adverse events or secondary cancers.

AUTHORS' CONCLUSIONS

In summary, the currently available evidence suggests a strong PFS benefit for HDT + ASCT compared with chemotherapy or immuno-chemotherapy in previously untreated patients with FL. No statistically significant differences in terms of OS, TRM and secondary cancers were detected. These effects are confirmed in a subgroup analysis (one trial) adding rituximab to both treatment arms. Further trials evaluating this approach are needed to determine this effect more precisely in the era of rituximab. Moreover, longer follow-up data are necessary to find out whether the PFS advantage will translate into an OS advantage in previously untreated patients with FL.There is evidence that HDT + ASCT is advantageous in patients with relapsed FL.

Induction of autologous graft-versus-host disease: results of a randomized prospective clinical trial in patients with poor risk lymphoma

The results of blood or marrow transplantation in patients with chemorefractory aggressive lymphoma, that is, those not responding to conventional-dose chemotherapy at the time of transplant, have been poor. The relapse rate has been high after autologous bone marrow transplant, whereas allogeneic transplantation has been associated with excessive transplant-related toxicity. Administration of cyclosporine after autologous transplantation can induce an autoreactive syndrome that resembles graft-versus-host disease (GVHD). This syndrome, named autologous graft-versus-host disease, has clear antitumor activity in animal models that can be enhanced by the addition of cytokines such as gamma-interferon and interleukin-2. A randomized, prospective study was conducted to evaluate the antitumor effect of autologous graft-versus-host disease induced with cyclosporine, and augmented by the administration of gamma-interferon and interleukin-2 in patients with chemorefractory Hodgkin and aggressive non-Hodgkin lymphomas. Fifty-one patients were randomized, 24 to the autologous GVHD induction arm, and 27 to the noninduction arm after autologous transplant using mobilized peripheral blood stem cell (PBSC) grafts. There were no differences in treatment-related mortality, overall and event-free survival (OS, EFS) between both groups; however, in the induction arm, GVHD developed only in 4 patients. The administration of oral cyclosporine followed by interleukin-2 and gamma-interferon is generally not well tolerated, and does not appear to be an effective method to induce autologous GVHD in patients receiving autologous PBSC grafts.

Gastrointestinal graft-versus-host disease in recipients of autologous hematopoietic stem cells: incidence, risk factors, and outcome

Graft-versus-host disease (GVHD) is seen in skin, intestinal mucosa, and liver after autologous stem cell transplantation. We reviewed 681 consecutive patients to estimate the probability of gastrointestinal (GI) GVHD, response to treatment, risk factors for development, and effect on survival. GI GVHD was defined by persistent symptoms, mucosal abnormalities at endoscopy, and histology showing apoptotic crypt cells with or without lymphoid infiltrates. The proportion of patients with GI GVHD was 90/681 (13%). Nausea and vomiting occurred in 90% and diarrhea in 40%. The mean time to developing symptoms was day +15, that to histologically proven diagnosis was day +42, and that to starting prednisone treatment was day +45 after stem cell infusion. Treatment with a short course of prednisone effected durable responses in 79% of patients, and an additional 18% responded to a second course of prednisone. A multivariable logistic regression model demonstrated that the combined factor of a diagnosis of breast cancer or hematologic malignancy and female sex was statistically significantly associated with the probability of GI GVHD (P = .003). Survival in patients with GI GVHD was not statistically different than that in those without GVHD. We conclude that women with breast cancer or hematologic malignancy are more likely to develop GI GVHD after autologous transplantation, and that treatment with prednisone was effective.