Eugenia Gaozza

Fifty patients with recurrent Hodgkin's disease have been treated with high-dose therapy followed by autologous bone marrow transplantation. Forty-one patients had extranodal sites of relapse and 31 patients had constitutional symptoms. Two patients had been treated with mechlorethamine, vincristine, procarbazine, and prednisone (MOPP), lomustine, vinblastine, procarbazine, and prednisone (CcVPP), and radiation; 16 patients with MOPP, doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD), radiation, and lomustine, etoposide, and prednisone (CEP); 20 patients with alternating MOPP/ABVD, and 12 patients with alternating MOPP/ABVD followed by CEP and radiation. Eighteen patients had progressive disease during alternating MOPP/ABVD protocol alone or during conventional salvage therapy; 32 patients had had a complete remission with first-line therapy but later relapsed, 25 of them having received conventional salvage therapy; 12 achieved no response or progression ("resistant-relapse" patients); and 13 responded partially or completely ("sensitive-relapse" patients). Complete remission occurred in 24 patients (48%) with a median duration of 24 months and 16 patients (32%) achieved partial response with a median duration of 9 months, for an overall response rate of 80%. Ten patients failed to respond and died in progressive disease 1 to 10 months (median, 6 months) after transplantation. Toxicity was significant including infections (20%), liver enzymes and alkaline phosphatase elevations (100%), and carmustine lung toxicity (7%). There were two treatment-related deaths; one patient died of Pseudomonas aeruginosa septicemia and another patient died of cerebral hemorrhage. These results validate the procedure of high-dose therapy followed by autologous bone marrow transplantation in inducing remission in these advanced, highly-treated patients. Clearly, the question of whether high-dose therapy and transplantation will eventually supersede new conventional salvage therapies will be addressed after controlled clinical studies.

Twenty-five patients with acute non-lymphoblastic leukemia (ANLL) in first complete remission underwent autologous bone marrow transplantation (ABMT) between March 1984 and March 1988. The high-dose therapy employed included cyclophosphamide followed by total body irradiation (10 Gy), administered as a single dose. The median time from complete remission to ABMT was 5 months (range 2-9 months). Thirteen (52%) patients remain in complete remission 10-51 months (median 25 months) after ABMT and 14-60 months (median 32 months) after achieving complete remission. Causes of death were recurrent leukemia (five patients), parenchymal toxicities (acute respiratory distress syndrome, veno-occlusive disease) (three patients), cerebral haemorrhage (one patient), cerebral aspergillosis (one patient) and viral hepatitis (one patient). Six patients relapsed at a median of 5 months after ABMT (range 4-10 months). In conclusion, this study has resulted in survival data comparable to those of other institutions and the best reported outcomes of conventional chemotherapy.

Marrow cells were exposed to the LNL6 or G1N safety-modified variants of the N2 retrovirus, which contain the G418 bacterial resistance gene neo. The frequency of acquisition of the G418 resistance phenotype following exposure to LNL6 or G1N was compared among hematopoietic progenitor cells from the marrow of patients with chronic phase chronic myelogenous leukemia (CML), blast crisis CML, or from nonleukemic individuals. Under the conditions of our experiments, the myeloid committed progenitor cells from 3 of 6 nonleukemic individuals, 9 of 18 chronic-phase CML patients, and 2 of 4 blast crisis CML patients acquired resistance to at least 1 mg/ml G418 following incubation with cell-free supernatants from the PA317 LNL6 or PA317 G1N producer cell lines. Ten of the 32 colonies growing up in 0.8 mg/ml G418 from chronic-phase marrow exposed to LNL6 were shown to contain the neo gene by polymerase chain reaction (PCR) assay of DNA. These results were consistent with estimates of the transduction frequency based on acquisition of resistance to G418 as the number of colonies growing under G418 selection was always greater at 0.8 mg/ml G418 than at higher concentrations of G418 (1.0–1.4 mg/ml). The average transduction frequency at each G418 concentration (1.0, 1.2, and 1.4 mg/ml) in cells from blast crisis CML cells ranged from 2 to 14%, as measured by acquisition of G418 resistance. Chronic-phase CML showed slightly lower average frequencies of transduction (0.6–2.8% of the colonies are G418 resistant). The average transduction frequency of cells from nonleukemic marrow was as high as that seen from the marrow of chronic-phase CML individuals. These results have implications for retroviral marking strategies which are designed to follow the purging of blastic leukemia cells from the marrow of CML patients used for autologous bone marrow transplantation. Retroviral-mediated gene transfer using a marker gene (NeoR) is being used by a number of investigators to ask clinically important questions. One critical question is: When a leukemia patient who has received purged autologous bone marrow relapses, do the leukemic cells come from the administered marrow or do they arise endogenously in the patient's body? Etkin et al. demonstrate that cells from the marrow of patients with advanced stages of chronic myelogenous leukemia can be marked efficiently and, therefore, the question of relapse origin can be studied.