Liposomal daunorubicin (DaunoXome) for treatment of poor-risk acute leukemia.

Toxicity limits the use of anthracyclines in elderly sick patients and in heavily pretreated patients. Since the liposomal preparation of daunorubicin (DNR) (DaunoXome, or DNX) is expected to be less toxic than conventional DNR, we tested DNX combined with high-dose arabinosyl cytosine (HDAC) in 42 adult poor-risk acute leukemia patients. Thirty-one patients had acute non-lymphocytic leukemia (ANLL). Of these, 12 patients were newly diagnosed but were not eligible for standard induction treatment, 13 were in first relapse, and 6 were in second or subsequent relapse. Eleven patients had acute lymphocytic leukemia (ALL), in first (eight cases) or second (three cases) relapse. DNX was given i.v. in three doses of 80 or 100 mg/m(2) each (days 1-3) by a 60-min infusion in glucose 5%, followed by a 4-h infusion of HDAC 2 g/m(2) (days 1-5). Among 31 ANLL patients there were 16 (51%) complete remissions (CR), 5 deaths during induction, and 10 failures. Among 11 ALL patients there were 10 CRs and 1 failure. The response rate was not affected by the overexpression of MDR-related proteins (PgP, MRP-1, and LRP). Non-hemopoietic toxicity was negligible, with no intestinal toxicity and only one case of gram-negative bacteremia. We conclude that DNX, in combination with HDAC, is an effective treatment for poor-risk adult AL. Because of the low non-hematologic toxicity, it can be used to reinduce remission in poor-risk patients who are candidates for allogeneic bone marrow transplantation. The high CR rate observed in ALL requires confirmation.

Castleman's disease: an unusual cause of mediastinal mass and anemia.

We reported a case of thoracic localized, mixed variant, Castleman's Disease (angiofollicular lymph node hyperplasia) with a favourable clinical course presenting with mediastinal mass, microcytic anemia, mild thrombocytosis, polyclonal hyper-gammaglobulinaemia and without symptoms. Castleman's Disease must be always considered in the differential diagnosis of solitary mediastinal masses. Transthoracic fine needle aspiration cytology is usually nondiagnostic; in fact, cytologically, Castleman's Disease can be confused with other mediastinal lymphoproliferative disorders (such as thymomas or lymphomas). The optimal therapeutic approach is unknown but a complete surgical resection is treatment of choice for localized disease.

Liposome-encapsulated daunorubicin for PGP-related multidrug resistance.

The possibility that Daunoxome (DNX), a combination of daunorubicin (DNR) with a liposomal targeting system, escapes PGP was tested. Two pairs of leukaemic cell lines, each consisting of the parental non-multidrug resistance (MDR) line and of a MDR variant, were studied for cytotoxicity (MTT test) and for cellular DNR kinetic and accumulation (flow cytometry). DNX and free DNR were equally toxic against non-MDR cells, whereas the liposomal anthracycline was more toxic than the free drug against the MDR variant. Non-MDR cells accumulated DNR more rapidly when they were exposed to free DNR than to DNX, but MDR cells accumulated more DNR when they were exposed to DNX. The kinetics of DNX and free DNR were also studied in the blast cells of 41 cases of acute leukaemia and they were found to be related to blast cell PGP expression. In 15 cases with a low PGP expression intracellular DNR accumulation was faster and higher with free DNR than with DNX. In 26 cases with a high PGP expression the area under the curve was similar with DNX and free DNR, but the kinetics of intracellular DNR accumulation showed an early low plateau with free DNR and a slow and continuous increase with DNX. In MDR cell lines the ratio was more favourable to DNX than to free DNR. We conclude that liposome encapsulated DNR is partially protected from PGP and that it is worth testing for the treatment of PGP-positive acute leukaemia.