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Background & Method: The role of multidrug resistance (MDR) was investigated in patients with relapsed chronic lymphocytic leukemia (CLL). PSC-833 was added to modified VAD (a 4-day infusion of vincristine, doxorubicin, with oral dexamethasone, every 3 weeks), in an attempt to improve the response rate (21%) in a prior study. Laboratory tests to determine MDR and apoptosis proteins were correlated with response., Results: Two of the seven MDR-positive cases and one of the four MDR-negative patients achieved a partial response (no significant difference). No significant correlation with response was found in any of the laboratory tests for apoptosis., Conclusion: VAD plus PSC-833 had the same (21%) partial response rate as a prior ECOG study without PSC-833. No correlation of response with MDR or apoptosis testing was found. Other drug resistance factors must play a significant role in determining the response of relapsed patients with CLL.

Two cases of IgA multiple myeloma treated with syngeneic bone marrow transplant and a non-total body irradiation (TBI) conditioning regimen are reported. Both patients presented with stage III disease which responded to standard chemotherapeutic management. The myelo-ablative program for transplant consisted of busulfan and cyclophosphamide (Bu/Cy). Evaluation at 40 days post-transplant revealed no evidence of residual myeloma in either patient. One patient died of disseminated Aspergillus fumigatus at day 73 post-transplant. The other patient relapsed at 18 months post-transplant. This conditioning regimen shows efficacy in aggressive myeloma and could be considered earlier in the disease.

Partially purified platelet DNA polymerase (PDP) was able to synthesize DNA transcripts of platelet polyadenylated RNA. PDP was elevated in the earliest stages of CML and PV. In PV, successful chemotherapy resulted in rapid return of PDP to normal levels while in CML this was not the case. An hypothesis is presented proposing that PDP contributes to oncogenesis by regulating the expression of oncogenes.

Thirty-nine patients with Philadelphia chromosome-positive (Ph1) chronic myelocytic leukemia (CML) were monitored using cytofluorometry and cytogenetics. During chronic phase, abnormal populations could be detected using commercially available monoclonal antibodies. Most of these abnormal populations had either an HLA.DR+ or an OKM1+ HLA.DR- phenotype. Thirteen patients progressed to acute phase disease. Five patients with HLA-DR+ abnormal cells during chronic phase showed no clonal evolution detectable using standard cytogenetic techniques and underwent lymphoid transformation. Seven patients with OKM1+-HLA.DR- abnormal cells exhibited chromosomal abnormalities in addition to the Ph1 and progressed to a myeloblastic acute phase. One patient with HLA.DR+ OKM1+ 63D3+ abnormal cells in chronic phase showed clonal evolution and progressed to a myelomonocytic acute phase. These results suggest that cell surface markers on chronic phase cells can be used in conjunction with cytogenetic monitoring to predict the phenotype of cells involved in the acute transformation of CML. B cells (6, 13), but not T cells (18), bearing the Ph1 have been isolated from chronic phase CML patients. Thus cells other than those of myeloid lineage may be involved. Periodic cytogenetic monitoring has been shown to detect clonal evolution (i.e. genetic changes in addition to the PH1) in as many as 75% of patients prior to the acute phase (14, 37). However, neither cytogenetic changes nor morphologic analysis appear to predict the lymphoblastic type of transformation (14). Since fluorescence analysis of cell surface markers has shown reduced numbers of normal cells (28), the identity of the 'abnormal' cells was probed with antibodies recognizing a variety of markers on immature and mature lymphoid and myeloid cells. Not only were significant numbers of abnormal cells detected in the peripheral blood of chronic phase patients, but the phenotype of the abnormal population, in combination with cytogenetic analyses, predicted the type of blasts involved in acute phase disease.