J. A. Liu Yin

P-glycoprotein expression on acute myeloid leukaemia blast cells at diagnosis predicts response to chemotherapy and survival

P‐glycoprotein (Pgp) expression, which is associated with the multi‐drug resistance (MDR) phenotype, has been reported to be a useful predictor of treatment outcome in acute leukaemia. We have examined the expression of Pgp on acute myeloid leukaemia (AML) cells in 54 newly diagnosed patients, using a novel streptavidin‐biotin complex (ABC) technique, 56% of patients at diagnosis were positive for Pgp with JSB‐1, a monoclonal antibody that binds to an internal epitope of Pgp. All patients received intensive induction chemotherapy. Post‐remission treatment consisted of futher chemotherapy ± bone marrow transplantation. Complete remission (CR) rates were significantly lower in the Pgp positive group than in the Pgp negative group (60%v 92%; P= 0.02). The overall survival for Pgp‐positive patients was significantly shorter (329 v 534d, P= 0.004), disease‐free survival was also reduced but the difference was not statistically significant (median 277 v 522d, P= 0.16). In this study CD34 expression was not predictive of response to chemotherapy nor was it associated with Pgp expression. Our results confirm the prognostic value of Pgp expression in AML at diagnosis and we suggest that Pgp could be a useful therapeutic target for reversing multi‐drug resistance. Furthermore, our simple and sensitive method of detecting Pgp should enable widespread testing to be performed.

Detection of CBFB/MYH11 transcripts in patients with inversion and other abnormalities of chromosome 16 at presentation and remission

Summary .The pericentric inversion of chromosome 16 [inv(16)(pl3q22)] and t(16;16)(pl3;q22) are chromosomal rearrangements frequently associated with AML FAB type M4Eo resulting in the production of a fusion gene CBFB/ MYH11. We studied 17 patients with a chromosome 16 abnormality (eight M4Eo, two Ml, one M2, three M4 without abnormal eosinophils, three MDS) for the presence of CBFB/MYH11 transcripts using an RT‐PCR technique. 10 AML patients with inv(16) tested RT‐PCR positive (eight at presentation, one in remission, one in remission and relapse). Three of these patients were originally reported by cytogenetic analysis to have del(16q22) but the positive RT‐PCR results prompted a cytogenetic re‐examination, resulting in the correction of the reports to inv(16). We show that although inv(16) is closely associated with AML M4Eo, it can also be detected in cases of AML M4 without abnormal eosinophils. Three cases of MDS with inv(16) were also RT‐PCR positive. Four patients with other chromosome 16 abnormalities were RT‐PCR negative. Four AML patients with inv(16) were studied in remission. All were RT‐PCR positive, including one patient in remission for 108 months and one 22 months post allogeneic bone marrow transplant. In the latter two remission patients, RT‐PCR evaluation was positive in bone marrow (BM) but not in peripheral blood, suggesting that BM may be the more informative. We conclude that this technique is valuable in the accurate molecular classification of AML, particularly as treatment options may be influenced by such information. Though RT‐PCR is highly sensitive in detecting CBFB/MYH11 fusion transcripts during remission, monitoring of minimal residual disease in patients with inv(16) remains to be established.

Mitozantrone and cytosine arabinoside as first‐line therapy in elderly patients with acute myeloid leukaemia

We have prospectively evaluated a regimen of mitozantrone and cytosine arabinoside (Ara‐C) as first‐line therapy in elderly patients with acute myeloid leukaemia (AML). One hundred and four patients with a median age of 68 (range 60–81) were studied, in whom 86 had de‐novo AML, and 18 had preceding myelodysplasia or secondary AML. Complete remission was achieved in 64% of de‐novo cases, in 28% of MDS/secondary cases, and in 58% overall. The incidence of early death within 28 d of chemotherapy was 11%. The median disease‐free survival (DFS) was 11 months with an actuarial DFS of 15% at 43 months. The median overall survival was 9 months with an actuarial survival of 10% at 44 months. The incidence of non‐haematological toxicity was acceptably low, and usually of mild to moderate severity. Quality of life was improved, or unchanged, in 90% of responders. We conclude that mitozantrone and ara‐C is an effective and well‐tolerated regimen which produces high remission rates in elderly patients with AML.

Treatment of relapse after allogeneic bone marrow transplantation with reduced intensity conditioning (FLAG ± Ida) and second allogeneic stem cell transplant

Acute leukaemias in relapse after allogeneic stem cell transplantation (SCT) respond poorly to donor leucocyte infusions (DLI) compared with chronic myeloid leukaemia (CML), at least in part because of faster disease kinetics. Fludarabine‐containing ‘non‐myeloablative’ chemotherapy followed by further allo SCT may offer more rapid and effective disease control. We report 14 patients with relapse after allo SCT for acute leukaemia [seven acute myeloid leukaemia (AML), five acute lymphoblastic leukaemia (ALL)] or refractory anaemia with excess blasts in transformation (RAEB‐t, n = 2) treated with fludarabine, high‐dose cytosine arabinoside (ara‐C) and granulocyte colony‐simulating factor (G‐CSF) with (n = 10) or without (n = 2) idarubicin (FLAG ± Ida) or DaunoXome (FLAG‐X) (n = 2) and second allo SCT from the original donor. Donors were fully human leucocyte antigen (HLA) ‐matched in 13 cases with a single class A mismatch in one. Actuarial overall survival was 60% and disease‐free survival was 26% at 58 months. Remissions after the second SCT were longer than those after the first bone marrow transplantation (BMT) in eight of the 13 assessable patients to date. Haematopoietic recovery was rapid. Transplants were well tolerated with no treatment‐related deaths. The major complication was graft‐versus‐host disease (GvHD, acute  grade II−2 cases, chronic – eight cases, two limited, six extensive) although there have been no deaths attributable to this. FLAG ± Ida and second allo SCT is a safe and useful approach and may be more effective than DLI in the treatment of acute leukaemias relapsing after conventional allo SCT.

ACUTE MYELOID LEUKAEMIA IN THE ELDERLY: BIOLOGY AND TREATMENT

With improved supportive care and very intensive chemotherapy, with or without bone marrow transplantation, it is now possible to cure an increasing number of younger patients with acute myeloid leukaemia (AML). However, approximately 60% of patients with AML are over 60 years old (Brinker, 1982). and the management of such elderly patients has been generally unsatisfactory. Thus it is timely to review the specific problems which elderly patients with AML pose. and discuss the various treatment modalities currently available.

Prognostic factors in elderly patients with acute myeloid leukaemia: development of a model to predict survival

Summary With an increasing number of elderly patients presenting with acute myeloid leukaemia and with recent reports of worthwhile remission rates and survival times following treatment with intensive chemotherapy, there is a pressing need to identify criteria to assist in the selection of appropriate therapy for elderly patients. We have performed multivariate Cox proportional hazard regression analysis of data prospectively collected during the treatment of 104 patients aged 60 and over treated in a multi‐centre study with a standardized regimen of mitozantrone and cytosine arabinoside for induction and consolidation. Four readily available parameters, namely urea, performance status, peripheral blood blast count and presence of hepatomegaly, were identified from which a prognostic model to predict survival has been developed. The model was found to be accurate in predicting survival in the cohort of patients from which it was developed, but needs to be validated in a further test population studied prospectively. Its simplicity suggests that it may be particularly useful in the selection of elderly patients with AML most likely to benefit from intensive chemotherapy.

The in vitro effect of pegylated recombinant human megakaryocyte growth and development factor (PEG rHuMGDF) on megakaryopoiesis in normal subjects and patients with myelodysplasia and acute myeloid leukaemia

Mpl ligand is a recently cloned haemopoietic growth factor that stimulates megakaryopoiesis in vitro and in vivo. We describe the in vitro effect of a truncated form of Mpl ligand, recombinant human megakaryocyte growth and development factor (rHuMGDF), on megakaryopoiesis in bone marrow from normal subjects and patients with myelodysplastic syndrome (MDS) and acute myeloid leukaemia (AML). We used both semi‐solid and suspension culture techniques to assess the effect of pegylated (PEG) rHuMGDF on megakaryocyte colony growth (CFU‐Mk) and on the production of CD61+ cells in 7 d suspension cultures. PEG rHuMGDF increased CFU‐Mk growth and CD61+ cell production in a dose‐dependent fashion in all normal marrows tested. Normal CFU‐Mk growth was increased threefold with the addition of 10 ng/ml PEG rHuMGDF to cultures and CD61+ cells were increased 8–10‐fold by the same dose. Although increased CFU‐Mk growth was only seen in 1/10 AML and 6/16 MDS marrows, CD61+ cell numbers in suspension culture were increased in 9/13 AML and 12/15 MDS samples, responses ranged from very limited to normal magnitude. There was no correlation between platelet count and CFU‐Mk number, CD61+ cell number or response to PEG rHuMGDF. We did not find any increased CFU‐GM colony or cluster growth in response to PEG rHuMGDF and the CD61+ cells produced in suspension culture had features of megakaryocytic differentiation. These data suggest that PEG rHuMGDF can enhance megakaryocyte proliferation in some patients with MDS and AML, and may have a role in the treatment of thrombocytopenia in these patients.

Therapy-related acute promyelocytic leukaemia.

We report three patients with acute promyelocytic leukaemia (APL) occurring after treatment for other malignant disorders. One patient had had razoxane (a drug affecting DNA topoisomerase II) for cancer of the colon, and the other two had had treatment for cancer of the breast. Two out of the three patients went into complete remission. We review the published literature on therapy‐related acute promyelocytic leukaemia (t‐APL) and suggest that it is a genuine clinical entity which may be caused by drugs affecting DNA topoisomerase II, and has a prognosis similar to de novo APL.

Effect of gemtuzumab ozogamicin on acute myeloid leukaemia blast cells in vitro, as a single agent and combined with other cytotoxic agents

The effect of gemtuzumab ozogamicin (GO) alone, or combined with low‐dose cytarabine or etoposide, on the proliferation of acute myeloid leukaemia blast cells in vitro was investigated. GO alone induced a dose‐dependent inhibition of proliferation although an increase in apoptosis was only seen in a minority of patients. A correlation was found between PgP function and GO sensitivity but not between CD33 or PgP expression and GO. Combinations of GO with varying concentrations of cytarabine or etoposide were additive in inhibiting proliferation, reducing cell viability and increasing apoptosis.

The clinical usefulness of C-reactive protein measurements

Pyrexia in the neutropenic patient is a common problem in haematology. Its occurrence increases with the severity and duration of neutropenia (Bodey et al, 1966) and, with presentday cytotoxic regimens, is almost inevitable. Parented broad-spectrum antibiotics are usually administered to cover the possibility of bacterial infections, although blood products, drug allergies, disease activity or infections due to viral, protozoal or fungal agents can all cause pyrexia. Clinical indicators are often misleading. To await culture results increases mortality and prompt antibiotic administration is indicated (Whitecar et al, 19 70). C-reactive protein (CRP) levels rise rapidly following an endotoxin stimulus from a normal value of < 1 mg/l to values several hundred-fold higher within 24 h (Pepys, 1981). The elimination of CRP is equally rapid with a half-life of 8.9 h (Gewurz et al, 1982). In the neutropenic patient CRP has been shown to rise quickly following the onset of a bacterial infection, usually to values > 100 mg/l (Mackie et al, 1979; Rose et al, 1981; Schofield et al, 1982; Williams P t al, 1982). Smaller rises in CRP level may occur during pyrexias due to drug allergies, viral and fungal infections, disease activity (except in lymphomas where it may bc quite high) and reactions to blood products but does not usually exceed 100 mg/l (Gozzard et ul, 1986). CRI’ levels are unaffected by the disease activity of acute leukaemia (Peltola et al, 19 8 3 ) . Tissue injury stimulates CKP production but a supervening bacterial infection further elevates the level (Rose et al, 1981). Necrosis of the bone marrow following cytotoxic administration does not cause a CRP elevation. Fungal infections produce variable effects but deep-seated infections can elevate CRP above 100 mg/l (Kostiala, 1984). Although CRP levels are usually raised during bacterial infections the level on the first day of pyrexia may be < 100 mg/l. Consequently CRP estimations cannot define the necessity for antibiotic administration. However, CRP rises over the first 48-72 h and in successfully treated incidents the level falls with resolution of pyrexia and clinical improvement. Not uncommonly the CRP level falls before the pyrexia remits, giving early confirmation of a successful outcome. The shortest half-life in clinical practice is 24 h but a variable fall in CRP level is recognized, possibly reflecting a slowly remitting bacterial infection. This can only be confirmed by further clinical trials. The most informative results occur in those circumstances in which the temperature is suppressed without resolution of the infection. If clinical indicators were followed, antibiotics might be stopped after several days of normal temperature, often with reappearance of pyrexia 2-3 d later. Indeed, in this situation it is not uncommon for pyrexia to recur during treatment, a difficult situation for the clinician. CRP levels are sustained, even though the temperature is abolished, indicating incomplete or Correspondence: Dr D. I. Gozzard, Department of Clinical Haematology, The Royal Infirmary. Manchester M13 9WL.