Michael Colvin

4-Hydroperoxyclophosphamide: a model for eliminating residual human tumour cells and T-lymphocytes from the bone marrow graft

Summary. Autologous bone marrow transplantation in acute leukaemia carries the risk of relapse from reinfusion of tumour cells present in marrow collected in remission and cryopreserved. An effective method for clearing marrow of tumour cells in required for a successful outcome. In the animal model 4‐hydroperoxycyclophosphamide (4‐HC) has proved to be effective in eliminating tumour cells from an autologous marrow graft. In the present studies, the in vitro effect of short‐and long‐term marrow cell incubation with 4‐HC on haemopoietic stem cells was investigated to determine the maximum concentration of 4‐HC that can be used for in vitro incubation without destroying the capacity of the marrow to effect complete haematological recovery as judged by residual CFUc content. However, loss of CFUc may not necessarily parallel survival of pluripotential stem cells. 4‐HC was also shown to be effective against peripheral T‐lymphocytes. Its possible therapeutic use in preventing or ameliorating graft‐versus‐host disease in allogeneic marrow grafts by preincubation with 4‐HC prior to transplantation is discussed.

Hypersensitivity reaction to a metabolite of cyclophosphamide

Generalized urticaria and fever were noted in a patient with IgA (kappa) myeloma after intravenous cyclophosphamide. Intradermal skin testing revealed no reaction to cyclophosphamide and its analog, isophosphamide. However, phosphoramide mustard, a principle metabolite of cyclophosphamide, evoked an immediate wheal-and-flare response. Subsequent therapy with isophosphamide was well tolerated. These findings suggest that acute hypersensitivity reactions to cyclophosphamide are due to its metabolites and can be delineated with skin testing.

Validity of skin tests to cyclophosphamide and metabolites

fapyridine is believed to be the active compound. There is, however, no doubt that the complete molecule is also an active drug.4 The toxicity of the drug is well-known because of its long use in the treatment of inflammatory bowel disease. The mode of action of the drug is unclear. An interesting effect is its inhibition of IgE-mediated mast cell degranulation.5 This may have particular relevance in these patients, since chronic idiopathic urticaria is typified by an increase in I:he number of mast cells intralesionally. The results in these patients have been gratifying. The dosag,e regimen was that of incremental increases of 500 mg every 5 days to a maximum of between 2 and 3 gm a day, depending on tolerance and response. Tolerance has been good, and no unusual or increased incidence of side effects has been noted to date. It is suggested that any patients with severe corticosteroiddependent chronic idiopathic hives be considered for a trial of sulfasalazine as an alternative agent.

Time Resolved Laser Desorption

The combination of laser ionization and mass spectrometry has been used for a number of years for elemental analysis of solid surfaces [1] and the pyrolysis of nonvolatile compounds [2]. However, an article by KISTEMAKER et al. [3] in 1978 focussed attention on the use of laser desorption for the analysis of large, nonvolatile bio-organic molecules, using conditions which produce intact molecular ions. There have been a number of contributions since [4–9] which have generally indicated that the kinds of ions produced by laser desorption are similar to those common in spectra produced by field desorption, plasma desorption, secondary ion mass spectrometry, thermal desorption, and fast, atom bombardment (Fig. 1.).

Dose-response effects of 4-hydroperoxycyclophosphamide on human T and B cell function in vitro.

4-Hydroperoxycyclophosphamide (4-OOH-CYP) is spontaneously converted in aqueous solution to 4-hydroxycyclophosphamide (4-OH-CYP), the major active metabolic of cyclophosphamide. We studied the dose related effects of in vitro treatment with 4-OOH-CYP on human T- and B cell-mediated immune responses. T-cell proliferation to mitogens and alloantigens was only partially inhibited even relatively high-doses of 4-OOH-CYP (greater than 6-12 micrograms/ml). In contrast cytotoxic functions of activated T-cells and natural killer (NK) cells were inhibited at lower doses (3-6 micrograms/ml). PWM induced in vitro synthesis of IgG by B-cells was inhibited at less than 3 micrograms/ml of 4-OOH-CYP. These data indicate that 4-HOO-CYP has selective, dose-dependent effects on human T and B cells in vitro.

Cyclophosphamide and dimethylsulfoxide in the treatment of squamous carcinoma of the lung

SummaryTo determine whether dimethylsulfoxide (DMSO) can potentiate antitumor activity of cyclophosphamide (CYC) in patients with squanmous cell carcinoma of the lung, 14 patients were treated with 5 l of a 5% or 6% DMSO solution PO over 3 days and 1,500 mg CYC/m2 IV as a 60-min infusion on the third day of treatment. Serial blood, CSF, and urine samples were collected to assess the pharmacokinetics of CYC. Courses were repeated every 3–4 weeks. No antitumor responses were observed. Toxicity was mainly hematologic and similar to that of CYC alone. There was one death from infection during granulocytopenia. Nonhematologic toxicity was moderate to severe and included nausea (14 patients) and vomiting (five patients). The plasma pharmacokinetics of CYC in this study are similar to previously reported results for CYC alone, but the 24-h urinary excretion of CYC in our study is much lower than previously reported. Further studies in tumors more responsive to CYC may be warranted.