Pilot study of the combination of melphalan, carboplatin and etoposide as a conditioning regimen for relapsed lymphoma patients

Plerixafor-aided Mobilization of Peripheral Blood Hematopoietic Stem Cells to Support Subsequent High-dose Chemotherapy After a Prior Autologous Transplant

BACKGROUND

An appreciable proportion of patients in need of salvage high-dose chemotherapy (HDC) and autologous peripheral blood stem cell (PBSC) transplantation (PBSCT) fail to mobilize adequate numbers of hematopoietic progenitors, and plerixafor is applied for that purpose. Limited data exist on remobilization of PBSCs in patients who have relapsed after prior HDC + PBSCT. Herein, we report on consecutive patients that had undergone successful prior single or tandem HDC for a variety of malignant neoplasms in our institution, and later required re-mobilization of PBSCs in order to support further HDC cycles.

PATIENTS AND METHODS

Plerixafor was administered in combination with granulocyte-colony stimulating factor alone, or after mobilizing chemotherapy. Five patients, 2 B-cell non-Hodgkin lymphomas, 1 multiple myeloma, 1 germ-cell tumor, and 1 Ewing sarcoma, having relapsed after prior HDC + PBSCT, were deemed candidates for further cycle(s) of PBSC-supported HDC. Plerixafor was applied in a "just-in-time" strategy after low CD34+ numbers were measured on the first day of anticipated hematopoietic stem cell collection (non-Hodgkin lymphoma, germ-cell tumor, and Ewing sarcoma), or pre-emptively in multiple myeloma.

RESULTS

Successful collection of adequate PBSCs was achieved in all patients, from 1.8 to 3.8 × 10⁶/kg after a median of 2 (range, 1-3) leukaphereses; 4 of 5 patients underwent subsequent HDC + PBSCT and engrafted after a median of 11 days (range, 9-55 days) and 25 days (range, 17-76 days) for neutrophils and platelets, respectively.

CONCLUSION

Plerixafor proved effective to mobilize adequate numbers of PBSCs in individual patients with relapsed malignancies after prior single or tandem HDC + PBSCT. These PBSCs could establish sustained multi-lineage hematopoietic engraftment without any sequelae.

Potential of chemo-immunotherapy and radioimmunotherapy in relapsed primary central nervous system (CNS) lymphoma

Five patients with relapsed PCNSL were given chemo-immunotherapy (rituximab followed by carboplatin and methotrexate) with osmotic blood-brain barrier (BBB) opening. Four patients achieved CR and one patient had stable disease. Two patients (2/5) had durable responses (survival: 230+, 122+, 82, 42, 38 weeks). One patient later received Indium-111-ibritumomab tiuxetan and Yttrium-90-ibritumomab tiuxetan intravenous, without BBB opening. There was good uptake of Indium-111 ibritumomab tiuxetan in tumor on SPECT scan after 48 h. Estimated radiation doses to brain around and distant from tumor were within safe limits. After Ytrium-90 ibritumomab tiuxetan there was CR in enhancing tumor where the BBB was leaky, but lesions occurred in other brain regions, where the BBB was intact during Yttrium-90 ibritumomab tiuxetan infusion. Imaging and dosimetry with Indium-111 ibritumomab tiuxetan and efficacy with Yttrium-90 ibritumomab tiuxetan suggest the need for future enhanced CNS delivery when using monoclonal or radiolabeled antibodies, as intravenous delivery alone may provide modest clinical benefit due to limited BBB permeability.

Current status and future of relapsed primary central nervous system lymphoma (PCNSL)

The treatment of primary central nervous system lymphoma (PCNSL) has centered around high-dose methotrexate and radiotherapy (RT). Methotrexate administered intra-arterially (IA) with blood-brain barrier disruption (BBBD) and without RT, has been a highly effective treatment with a 5 year survival of 42% without cognitive loss. The purpose of this analysis is to determine responses for patients with relapsed PCNSL treated with second line IA carboplatin-based chemotherapy with BBBD. Between February 1991 and April 2000, 37 relapsed PCNSL patients, most who failed front line therapy with methotrexate based chemotherapy, were treated at Oregon Health & Science University (OHSU) and Hadassah Hebrew University Hospital (HHUH) with IA carboplatin-based chemotherapy with BBBD. Nine patients had prior RT. The mean age was 57.5 years, and all but 1 patient were treated within 8 months after relapse. The median time for survival from first IA carboplatin/BBBD treatment was 6.8 months;however, 7 out of 37 patients survived > or = 27 months. Nine patients had radiographic complete response (CR), 4 patients had radiographic partial response (PR), 12 had stable disease (SD), 10 had progressive disease (PD), and 2 were non-evaluable. The median time to failure for patients with CR and PR was 9.1 months. One long-term survivor is alive at 91.0 months from first carboplatin/BBBD treatment. In conclusion, we show that relapsed PCNSL has shown sensitivity to second line IA carboplatin-based chemotherapy with BBBD. We have developed a new protocol using i.v. rituximab prior to BBBD with IA carboplatin, i.v. cyclophosphamide and i.v. etoposide phosphate. The long-term program goal is to consolidate dose-intensive chemotherapy with monoclonal antibody directed radiation. Because patients with recurrent PCNSL commonly continue to relapse even after obtaining a complete response to enhanced chemotherapy treatment, patients w ho complete or fail the above carboplatin/BBBD treatment regimen will be offered consolidation with radioimmunotherapy using zevalin (Ibritumomab tiuxetan), IDEC-2B8 conjugated with yttrium-90 (90Y).