Reovirus as a successful ex vivo purging modality for multiple myeloma

Autologous stem cell rescue (ASCT) following high-dose myeloablative chemotherapy is considered to be a therapeutic option for many multiple myeloma (MM) patients; however relapse post ASCT presents a major challenge. The oncolytic potential of reovirus has been previously demonstrated and is currently undergoing phase I monotherapy clinical trials for MM and phase II/III clinical trials for solid tumors. Here we tested the hypothesis that reovirus can successfully purge MM in a murine model that partially recapitulates human MM. RPMI 8226, MM1S, H929 and U266 human myeloma cell lines were exposed to reovirus and oncolysis was assessed. Apheresis product admixed with MM cells was purged with live reovirus (LV) or dead virus (DV) and purging efficacy was monitored via flow cytometry, reverse transcribed-PCR (RT-PCR) and disease relapse in non obese diabetic/severe combined immune deficient (NOD/SCID) mice. Significant LV purging was seen with MM1S, H929 and U266 and the complete ex vivo purging achieved with RPMI 8226 was confirmed by flow cytometry, RT-PCR and absence of disease relapse in vivo. Mice that received LV-purged autografts exhibited 100% survival in comparison to mice that received DV-purged controls. Reovirus's unique ability to kill MM while sparing hematopoietic stem cells places it as an attractive purging agent for MM during ASCT.

Overnight storage of autologous stem cell apheresis products before cryopreservation does not adversely impact early or long-term engraftment following transplantation

To reduce costs and avoid inconvenient overtime work, our institution changed policy in September 2000 so that autologous stem cell apheresis products were stored overnight before cryopreservation rather than immediately processed. This retrospective review was conducted to evaluate the possible impact of this policy change on hematopoietic engraftment following autologous stem cell transplantation (ASCT). In total, 229 consecutive lymphoma patients who underwent a single, unpurged ASCT in Calgary between January 1995 and November 2003 were evaluated. Of these patients, 131 patients' autografts underwent immediate processing and cryopreservation before September 2000, and 98 patients' autografts underwent next-day cryopreservation after overnight storage following this date. Results of univariate and multivariate analyses demonstrated no adverse effect of overnight storage before cryopreservation on the number of days to initial engraftment of platelets or neutrophils, on the proportion of patients with low blood counts 6 months post-ASCT, or on lymphoma relapse rates or overall survival post-ASCT. These data suggest that overnight storage of the autograft before cryopreservation does not adversely affect graft viability or influence long-term disease status, and support the continued use of overnight storage of stem cells before cryopreservation as a convenient, cost reduction measure.

Effect of complete response pre- and post- autologous stem cell transplantation in multiple myeloma

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Background: The value of achieving a complete response (CR) pre or post high dose therapy and autologous stem cell transplant (HDT-ASCT) in multiple myeloma is still uncertain. Knowing the impact of achieving a CR prior to HDT-ASCT on survival, may lead to the incorporation of novel therapeutic agents into the front line treatment of this disease. The aim of our study was to determine whether achieving a CR before or after HDT-ASCT affects overall survival (OS) in multiple myeloma patients. Methods: We performed a retrospective analysis of 88 consecutive myeloma patients receiving HDT-ASCT at our center from 1993 to 2004. The OS of patients achieving at least 90% reduction in their M-protein, i.e. complete response and very good partial response (CR/VGPR), pre or post HDT-ASCT, was compared to that of patients achieving a partial response or less (<90% reduction in M-protein). OS, defined as the number of months from HDT-ASCT to death or last follow up, was estimated by the Kaplan-Meier method. Response status was evaluated pre and at 100 days post HDT-ASCT. Results: Prior to HDT-ASCT, twenty-two (25%) patients achieved a CR/VGPR. Median follow-up time was 39 months for patients in CR/VGPR and 18 months for non-CR/VGPR group. OS at 5 years was 58% (95% CI: 21%-82%) for patients in CR/VGPR, compared to 69% (95% CI: 51%-81%) for all patients in PR or less prior to stem cell collection. Post HDT-ASCT, 48 (55%) patients achieved a CR/VGPR. Their OS estimate at 5 years was 67% (95% CI: 44%-82%) compared to 71% (95% CI: 27%-92%) for all other patients. Overall, 30% more patients achieved CR/VGPR post HDT-ASCT. However, the survival curves did not differ by response status pre or post HDT-ASCT (log-rank test p=0.58 and 0.57 respectively). Conclusions: Our results suggest that achieving a clinical CR/VGPR pre or post HDT-ASCT does not appear to impact OS. These results might have been influenced by the small sample size and the possible need for a longer follow-up time. A more robust definition of CR at the molecular level, plus the use of novel therapeutic agents in front-line treatment, may better define the impact of achieving CR in multiple myeloma.

No significant financial relationships to disclose.

Autologous transplantation for primary systemic AL amyloidosis is feasible outside a major amyloidosis referral centre: the Calgary BMT Program experience

Recent reports from large amyloidosis referral centers suggest that primary systemic AL amyloidosis patients treated with high-dose melphalan (HDM) and autologous stem cell transplantation (ASCT) survive longer than historical controls treated with less intensive chemotherapy, despite high transplant-related mortality (TRM) rates of >10%. A retrospective review was conducted to determine if the outcome of ASCT for AL amyloidosis at our institution was similar to that reported at major amyloidosis referral centers. Over a 7 year period, we treated a total of 15 AL amyloidosis patients with ASCT, including four with poor prognosis cardiac or multisystem involvement. No TRM was observed. Overall, 10 patients (67%) achieved a complete hematological response and four patients (27%) achieved a complete organ response. The 4-year event-free and overall survival rates were 60% (95% CI 32-89%) and 75% (95% CI 50-100%), respectively. One patient, who presented with cardiac failure and multiorgan involvement with colonic bleeding currently remains in complete remission 62 months post-ASCT. In conclusion, ASCT for primary AL amyloidosis can safely be performed at experienced transplant centers that are not associated with major amyloidosis referral centers, and is feasible for patients who have multisystem involvement, particularly for motivated patients with good performance status.