Role of hematopoietic stem cell transplant in the management of follicular lymphoma

Diagnosis and treatment of follicular lymphoma: where do we stand?

SUMMARY The treatment of follicular lymphoma (FL) has advanced in the past decade. The routine use of monoclonal antibodies, arrival of bendamustine and application of radioimmunotherapy have ushered in major improvement in response rates for patients with indolent lymphoma. Studies have documented an improvement in progression-free survival and overall survival with chemoimmunotherapy followed by maintenance rituximab. The purpose of this review is to share an overview of recent advances in clinical care and research underway that will be incorporated into clinical practice in the foreseeable future. We will restrict our review to FL because the wide variety of types of indolent lymphoma makes it impossible to cover all of them in a brief review. FL is the most common indolent lymphoma and the general approach to diagnosis and treatment of this disease is often utilized as a foundation for the diagnosis and treatment of indolent lymphomas in general.

Who should be really considered as a poor mobilizer in the plerixafor era?

Patients with a number of peripheral CD34+ cells ≥20/μL have recently been defined in the literature as "poor mobilizers". We retrospectively reviewed medical records from a total of 248 patients affected by hematological malignancies or solid tumors undergoing peripheral blood stem cell collection following chemotherapy plus G-CSF. On the basis of the CD34+ cell peak in peripheral blood following mobilization therapy, patients were defined as good mobilizers (group A, CD34+ cells ≥20/μL), relative poor mobilizers (group B, CD34+ cells <20 and ≥8/μL) and absolute poor mobilizers (group C, CD34+ cells <8/μL). One hundred and seventy-seven (71%) patients resulted good mobilizers, 35 (14%) patients relative poor mobilizers and 36 (15%) patients absolute poor mobilizers. Target of stem cell collection was ≥2.0×10(6) CD34+cells/kg for each transplantation procedure. All patients in group A, 20 patients in group B (57%) and 1 patient in group C (2.7%) were able to collect ≥2.0×10(6) CD34+cells/kg. The multivariate analysis confirmed that more than three lines of previous chemotherapy and a previous autologous PBSC transplantation negatively affect mobilization of CD34+ cells in peripheral blood. Our data suggest that a number of CD34+ cells ≥20/μL does not always result in a failed stem cell collection and in fact in our patient series more than 70% of the patients defined as poor mobilizers have indeed collected the minimum number of 2.0×10(6) CD34+cells/kg required for a successful transplantation. The use of new agent such as CXCR4 antagonist plerixafor might further improve mobilization efficacy in such patients.

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.

Proposed definition of 'poor mobilizer' in lymphoma and multiple myeloma: an analytic hierarchy process by ad hoc working group Gruppo ItalianoTrapianto di Midollo Osseo

Many lymphoma and myeloma patients fail to undergo ASCT owing to poor mobilization. Identification of poor mobilizers (PMs) would provide a tool for early intervention with new mobilization agents. The Gruppo italianoTrapianto di Midollo Osseo working group proposed a definition of PMs applicable to clinical trials and clinical practice. The analytic hierarchy process, a method for group decision making, was used in setting prioritized criteria. Lymphoma or myeloma patients were defined as ‘proven PM' when: (1) after adequate mobilization (G-CSF 10 μg/kg if used alone or ⩾5 μg/kg after chemotherapy) circulating CD34⁺ cell peak is <20/μL up to 6 days after mobilization with G-CSF or up to 20 days after chemotherapy and G-CSF or (2) they yielded <2.0 × 10⁶ CD34⁺ cells per kg in ⩽3 apheresis. Patients were defined as predicted PMs if: (1) they failed a previous collection attempt (not otherwise specified); (2) they previously received extensive radiotherapy or full courses of therapy affecting SC mobilization; and (3) they met two of the following criteria: advanced disease (⩾2 lines of chemotherapy), refractory disease, extensive BM involvement or cellularity <30% at the time of mobilization; age ⩾65 years. This definition of proven and predicted PMs should be validated in clinical trials and common clinical practice.