Sequentially administered 5-azacitidine and amsacrine in refractory adult acute leukemia: a phase I-II trial of the Southeastern Cancer Study Group

The Southeastern Cancer Study Group conducted a phase I-II trial of sequentially administered 5-azacitidine and amsacrine in patients with refractory adult acute leukemia from September 1980 to March 1983. The 5-azacitidine was administered by continuous iv infusion on Days 1-4 at doses ranging from 112 to 200 mg/m2/day, while amsacrine was given at doses ranging from 75 to 150 mg/m2/day on Days 5-8. The doses of 5-azacitidine and amsacrine were alternately escalated through six dose levels during the phase I portion of the trial. Of 128 patients entered, 102 (80%) were evaluable for response. Remission was achieved in 13 of 80 evaluable patients with acute myeloid leukemia, in one of 12 evaluable patients with acute lymphoid leukemia, and in none of 11 patients with blastic transformation of chronic granulocytic leukemia. Three remissions occurred in patients with acute myeloid leukemia who were refractory to initial induction chemotherapy with cytarabine and anthracycline combination chemotherapy. Remissions were relatively durable, lasting a median of 28 weeks in the 13 patients with refractory acute myeloid leukemia (range, 14-54 weeks). Toxic effects included universal severe myelosuppression, hyperbilirubinemia at a frequency and severity similar to those seen with amsacrine used as a single agent, moderately severe stomatitis and diarrhea, three incidents of amsacrine-related cardiac dysrhythmia, and a single case of probable drug-related cardiomyopathy. This combination has activity in the treatment of myeloid leukemia, which is primarily resistant to cytarabine and anthracyclines, and could have a role in primary management.     

Reliability of radiographic assessment of distraction osteogenesis site

The presence of three of four continuous cortices on anteroposterior and lateral radiographs has been stated to be an indication of bony healing of distraction osteogenesis. In this study the authors assessed the level of agreement of radiographic assessment of bony union. Forty-two lower extremity radiographs of consolidating distraction gaps were reviewed by nine examiners on two occasions for number of cortices and whether fixator removal was indicated. For number of cortices, the kappa coefficients for interobserver and intraobserver variability were 0.127 and 0.290. For fixator removal, the interobserver and intraobserver coefficients were 0.352 and 0.461. Variation in assessment of number of cortices was slightly better than chance, indicating an inadequate measure of healing. The clinicians used radiographic criteria other than three of four cortices for fixator removal. The decision to remove an external fixation device based on radiographic assessment alone resulted in intraobserver and interobserver variability moderately above chance.     

Spontaneous mutant frequency and mutation spectrum for gene A of phiX174 grown in E. coli

The use of transgenic targets for measuring mutant frequencies in mammalian tissue requires an estimate of the mutant frequency that results from recovery of the transgene in bacterial recovery systems. In this study, we have determined the spontaneous mutant frequency, estimated the mutation rate, and ascertained the mutation spectrum for gene A of phiX174 grown in E. coli strain CQ2 from 156 small independent cultures. The mutant frequency of 12 of the 156 cultures was 17 +/- 1.0 x 10(-6) and the estimated mutation rate per gene replication was 7.4 +/- 2.3 x 10(-6). The mutant frequency and spectrum from E. coli were not significantly different from that of solvent-treated embryonic mouse cells in culture, 19 +/- 0.5 x 10(-6) (Valentine CR et al. [2002]: Environ Mol Mutagen 39:55-68), indicating that those spontaneous mutants were primarily derived from E. coli. The E. coli spectrum was heavily weighted toward two major target sites (hot spots), 4225A-->G (56%) and 4218G-->A or C (20%). Four new target sites and one new mutational event were recovered by the gene A forward assay. A mutant spectrum from an expanded phage stock was also determined to assess the effects of propagating the virus. This mutant frequency was higher (6 x 10(-4)), contained more double mutants (15% compared to 0.6%), and had a significantly different spectrum from the spectrum for independent cultures (fewer A:T-->G:C and G:C-->C:G changes and more G:C-->A:T; P < 0.002). The E. coli mutation spectrum will be useful for determining the origin of gene A mutation in tissues of phiX174 transgenic mice.     

Rhabdomyosarcoma and undifferentiated sarcoma in the first two decades of life: a selective review of intergroup rhabdomyosarcoma study group experience and rationale for Intergroup Rhabdomyosarcoma Study V

PURPOSE: To review the importance of prognostic factors in developing new protocols for children with rhabdomyosarcoma (RMS). PATIENTS AND METHODS: Four studies conducted by the Intergroup Rhabdomyosarcoma Study (IRS) Group from 1972 through 1991. RESULTS: Favorable prognostic factors are: (1) undetectable distant metastases at diagnosis; (2) primary sites in the orbit and nonparameningeal head/neck and genitourinary nonbladder/prostate regions; (3) grossly complete surgical removal of localized tumor at the time of diagnosis; (4) embryonal/botryoid histology; (5) tumor size < or = 5 cm; and (6) age younger than 10 years at diagnosis. The IRS-V protocols are risk-based and refine therapy by reducing exposure to cyclophosphamide and radiation therapy (XRT) in patients at low risk while adding new, active agents such as topotecan or irinotecan to the standard therapy of vincristine, actinomycin D, and cyclophosphamide (VAC) plus XRT for patients with unfavorable histology or advanced disease. Collection of biologic specimens from patients with newly diagnosed disease continues to identify other factors that may distinguish patients with favorable features from those who need more intensive therapy. A new protocol that takes into account their previous treatment is needed for patients with recurrent disease. This program (being planned) does not include bone marrow/stem cell reconstitution because this strategy has thus far failed to improve survival rates of patients with metastases at diagnosis. CONCLUSION: Better understanding of biologic differences and new, active agents are needed to improve outcome of patients with unfavorable features at presentation.