Molecular heterogeneity in complete cytogenetic responders after interferon-alpha therapy for chronic myelogenous leukemia: low levels of minimal residual disease are associated with continuing remission. German CML Study Group and the UK MRC CML Study Group.

A substantial minority of patients with chronic myelogenous leukemia (CML) achieve a complete response (CR) to treatment with interferon-alpha (IFN), defined as the disappearance of Philadelphia chromosome-positive metaphases. Currently it is unclear how long IFN treatment should be continued for such patients. We used a competitive reverse transcriptase-polymerase chain reaction (RT-PCR) to quantify levels of BCR-ABL transcripts in 297 peripheral blood specimens collected from 54 patients who had achieved CR with IFN. The median duration of observation was 1.9 years (range, 0.3-11.0 years). Total ABL transcripts were quantified as internal control and results were expressed as the ratio BCR-ABL/ABL. All 54 patients had molecular evidence of residual disease, although 3 patients were intermittently PCR negative. The median BCR-ABL/ABL ratio at the time of maximal response for each patient was 0.045% (range, 0%-3. 6%). During the period of observation 14 patients relapsed, 11 cytogenetically to chronic phase disease and 3 directly to blastic phase. The median ratio of BCR-ABL/ABL at maximal response was significantly higher in patients who relapsed than in those who remained in CR (0.49% versus 0.021%, P < 0.0001). Our findings show that the level of residual disease falls with time in complete responders to IFN, but molecular evidence of disease is rarely if ever eliminated. The actual level of minimal residual disease correlates with the probability of relapse. We suggest that for patients who reach CR, IFN should be continued at least until relatively low levels of residual leukemia are achieved. (Blood. 2000;95:62-66)

A new prognostic score for survival of patients with chronic myeloid leukemia treated with interferon alfa. Writing Committee for the Collaborative CML Prognostic Factors Project Group.

BACKGROUND: Interferon alfa is a conservative and widely used alternative to bone marrow transplantation in treatment of patients with early chronic myeloid leukemia (CML). A meta-analysis was conducted to develop a reliable prognostic scoring system for estimation of survival of patients with CML treated with interferon alfa. METHODS: Patients treated in prospective studies, including major randomized trials, were separated into learning and validation samples. Cox regression analysis and the minimum P-value approach were used to identify prognostic factors for patient survival and to discover groups in the learning sample with the greatest differences in survival. These findings were then validated by applying the new scoring system to patients in the validation sample. RESULTS: We collected data on 1573 patients who were participants in 14 studies involving 12 institutions; 1303 patients (learning sample, n = 981; validation sample, n = 322) were eligible for inclusion in this analysis, and their median survival time was 69 months (range, 1-117 months). Because two previously described prognostic scoring systems failed to discriminate risk groups satisfactorily, we developed a new scoring system that utilizes the following covariates: age, spleen size, blast count, platelet count, eosinophil count, and basophil count. Among 908 patients with complete data in the learning sample, three distinct risk groups were identified (median survival times of 98 months [n = 369; 40.6%], 65 months [n = 406; 44.7%], or 42 months [n = 133;14.6%]; two-sided logrank test, P< or =.0001). The ability of the new scoring system to discriminate these risk groups was confirmed by analysis of 285 patients with complete data in the validation sample (two-sided logrank test, P = .0002). CONCLUSIONS: A new prognostic scoring system for estimating survival of patients with CML treated with interferon alfa has been developed and validated through use of a large dataset.

Progress with interferon in CML--results of the MRC UK CML III study.

527 patients with CML were entered into the multicentre randomised MRC CML III study comparing IFN-alpha n1 to standard chemotherapy, either busulphan or hydroxyurea. Haematologic response to IFN as assessed by the level of control of the WCC predicted cytogenetic response to IFN. Cytogenetic response (< 80% Ph + ve) was seen in 22% of all patients randomised, 11% showing major or complete responses. Major cytogenetic response rate was 18% in Sokal low risk patients, 15% in intermediate risk patients but only 4% in high risk patients. Mantel Byar analyses allowing for time to response showed a survival advantage for cytogenetic responders compared to non-responders. In addition, cytogenetic non-responders to IFN did significantly better than chemotherapy-treated patients. Median survival for all patients was 61 months in the IFN treated groups and 41 months in the no-IFN group. For Ph + ve patients only, the median survival was 63 months compared to 43 months. Sub-group analysis comparing busulphan or hydroxyurea treatment in the IFN and no-IFN treatment arms showed a significant advantage for IFN-compared to busulphan, but no significant difference between IFN and hydroxyurea treated patients, although there was a trend favouring IFN. A proposed overview of all randomised trials comparing IFN to hydroxyurea should, by virture of larger numbers, enable a more accurate assessment of the probable benefit of IFN compared to hydroxyurea therapy.

Quantification of residual disease in chronic myelogenous leukemia patients on interferon-alpha therapy by competitive polymerase chain reaction.

Interferon-alpha (IFN-alpha) induces cytogenetic responses of variable degree in patients with chronic myelogenous leukemia (CML). We sought to establish the relationship between BCR-ABL transcript numbers measured by competitive 2-step reverse transcription polymerase chain reaction (RT-PCR) and cytogenetic status in CML patients treated with IFN-alpha. A total of 250 peripheral blood and 55 bone marrow samples with 127 Philadelphia chromosome positive (Ph+) and 6 Ph-/BCR-ABL+ CML patients were investigated. Twenty-one patients were studied at diagnosis with IFN-alpha, 24 had a complete cytogenetic response, 21 a partial response, 12 a minor response, 26 no response, and 23 were unknown. Using nested RT-PCR, all 305 samples were positive for BCR-ABL transcripts. To standardize results for variability in RNA and cDNA quantity and quality, we quantified total ABL transcripts in each sample as internal control. The validity of ABL as internal control was shown by comparison with glucose-6-phosphate dehydrogenase transcript levels in 145 samples. The median BCR-ABL transcript numbers (and BCR-ABL/ABL ratios expressed as percentages) were 400/micrograms RNA (O.04%) in complete responders, 20,500/micrograms RNA (7.1%) in partial responders, 170,000/micrograms RNA (21.0%) in minor responders, and 430,000/micrograms RNA (58.7%) in nonresponders (P < .001). The cytogenetic results correlated with the BCR-ABL transcript numbers (r = .82; P < .001) and BCR-ABL/ABL ratios (r = .84; P < .001). Grouping the ratios BCR-ABL/ABL as less than 2%, 2% to 14% and greater than 14% to compare with cytogenetic complete response, partial response, and minor/nonresponse, the concordance between the two methods was 82% (chi2 P< .0001). We conclude that quantitative PCR with internal controls is as sensitive and reliable method for monitoring patients on IFN-alpha and reduces the need for repeated marrow investigations.

Variable numbers of BCR-ABL transcripts persist in CML patients who achieve complete cytogenetic remission with interferon-alpha.

A substantial minority of patients with chronic myeloid leukaemia (CML) achieve a complete response to treatment with interferon-alpha (IFN-alpha), defined as the disappearance of Philadelphia chromosome positive metaphases or, for patients who are Philadelphia chromosome negative but BCR-ABL positive, the disappearance of the leukaemic clone as assayed by Southern blot. We have measured the levels of BCR-ABL transcripts in 20 such patients by quantitative PCR. Results were standardized for both quality and quantity of cDNA by quantification of ABL as an internal control. All 20 patients had evidence of residual disease; the median number of transcripts was 750/micrograms RNA (range 10-22,000) and the median BCR-ABL/ABL ratio was 0.17% (range 0.0008-3.6%). Our findings show that CML has not been eradicated in any patient and that the quantity of residual disease in complete responders may vary by as much as four orders of magnitude.

UK Medical Research Council randomised, multicentre trial of interferon-alpha n1 for chronic myeloid leukaemia: improved survival irrespective of cytogenetic response. The UK Medical Research Council's Working Parties for Therapeutic Trials in Adult Leukaemia.

Interferon-alpha may be better than cytotoxic drugs in the long-term management of patients with chronic myeloid leukaemia (CML) in chronic phase. To test this possibility 587 patients with CML in chronic phase were randomly allocated to receive lymphoblastoid cell-line interferon-alpha n1 (IFN-alpha, n = 293) or chemotherapy with busulphan or hydroxyurea (no IFN-alpha, n = 294) as maintenance after initial induction treatment with cytotoxic drugs. There was a significant survival benefit for patients in the IFN-alpha arm when analysed on the basis of intention to treat (2p = 0.0009). The median survival for those allocated IFN-alpha was 61 months and no IFN-alpha was 41 months. Out of 269 patients with Philadelphia-positive CML in the IFN-alpha arm with at least 6 months follow-up, 211 were evaluable for haematological response: 145 (68%) achieved good responses (A+ or A type), 37 (18%) had partial responses (B type) and 29 (14%) had poor responses (C type). Patients with types A and B responses had a better survival than those in the no IFN-alpha arm; patients with type C responses had survival equivalent to the no IFN-alpha arm. Of these 269 patients, 26 of whom had not started IFN-alpha, 59 (22%) achieved a significant degree of cytogenetic response but 210 (78%) did not have a response. Cytogenetic responders survived significantly longer than non-responders and even non-responders survived longer than patients in the no IFN-alpha arm. Since cytogenetic non-responders had worse than average prognostic features, they may also benefit from IFN-alpha therapy. We conclude that treatment with IFN-alpha prolongs the survival of patients with CML; benefits of IFN-alpha are not confined to cytogenetic responders but may extend to most, if not all patients receiving IFN-alpha treatment; and cytogenetic response to IFN-alpha treatment identifies patients with a relatively good prognosis.

Severe cytopenias associated with the sequential use of busulphan and interferon-alpha in chronic myeloid leukaemia.

We describe four patients who developed severe thrombocytopenia which progressed to aplasia after the use of alpha-interferon in maintenance therapy of chronic phase CML after busulphan induction. On reviewing over 400 patients in the MRC CML III trial we found that there is a risk of cytopenia developing after busulphan therapy and a lesser risk of cytopenias developing after alpha-interferon therapy. If the therapies are given in a sequential fashion the risk of cytopenia developing appears to be additive, may be pronounced, and may lead to clinically significant problems. Hydroxyurea alone does not lead to sustained cytopenia. Care should be taken to ensure that counts are stable after the use of busulphan before starting alpha-interferon as maintenance therapy.

Interferon in chronic myeloid leukemia. A workshop report.

The therapeutic efficacy of interferon-alpha (IFN-alpha) in the treatment of chronic myeloid leukemia is currently being tested in a number of institutional, interinstitutional, and international trials. There is no doubt that responses are achieved in many patients, and in a small subset complete eradication of clonogenic cells may be possible. However, it has not yet been shown that overall survival of patients treated with IFN-alpha is better than that of those treated with conventional cytoreductive drugs. There are still controversial opinions on problems such as dosages and duration of treatment, combination with cytostatic agents, definition of responses, and relevance of cytogenic and molecular data. An international workshop discussed the data on interferon therapy and attempted to define the role of interferon today in the management of chronic myeloid leukemia.

Thioguanine used in maintenance therapy of chronic myeloid leukaemia causes non-cirrhotic portal hypertension. Results from MRC CML. II. Trial comparing busulphan with busulphan and thioguanine.

Portal hypertension with varices developed in 18/675 patients with chronic myeloid leukaemia (CML) in a randomized trial comparing busulphan with busulphan and thioguanine. All 18 had received the drug combination and none busulphan alone (P less than 0.0001). Ascites was also seen significantly more often in the combination arm (P less than 0.05). These results strongly suggest that the addition of thioguanine was responsible for the development of portal hypertension. The histological features were predominantly those of non-cirrhotic portal hypertension--either idiopathic portal hypertension with minimal morphological abnormalities, nodular regenerative hyperplasia or in two cases leukaemic infiltration only was noted. Cirrhosis was present in 3/16 cases studied. Both treatment groups developed abnormal liver function tests during the chronic phase, but particularly with progression of the disease. During chronic phase abnormalities were significantly more frequent in those receiving busulphan and thioguanine-alkaline phosphatase (P less than 0.02), transaminases (P less than 0.04), bilirubin (P less than 0.05), multiple abnormalities (P less than 0.01). The development of portal hypertension was often associated with abnormalities of these tests; however, lack of specificity precludes their use as a predictor of subsequent clinical problems. Thioguanine confers no survival advantage in this disease. In view of its hepatotoxicity it should not be used routinely for maintenance of control in chronic phase CML.

Primary ileocecal lymphoma. A study of 22 patients.

Twenty-two patients with primary ileocecal non-Hodgkin's lymphoma were reviewed. Abdominal pain (67%), altered bowel habits (50%), and weight loss (50%) were the most common presenting symptoms and an abdominal mass was palpable in 50%. Sixteen (73%) had histologic evidence of local lymph node involvement at diagnosis and another two (9%) had nonhistologic evidence of nodal involvement. An abdominal computed tomography (CT) scan was the most helpful staging investigation. Twenty-one (95.5%) patients underwent surgical resection of their disease. Subsequent chemotherapy, with or without radio-therapy, appeared to prolong survival (median, 34 months versus 14 months). There were three treatment-related deaths. Neither the age of the patient nor the stage of disease at presentation (Ann Arbor) appeared to influence survival. Adequate initial surgery combined with chemotherapy may provide optimum therapy in patients with primary ileocecal lymphoma.

Therapeutic options in chronic myeloid leukaemia.

The treatment of CML is unsatisfactory. Only bone marrow transplantation offers the possibility of cure. At present all other therapies are palliative and none has been shown to extend survival consistently. Busulphan and hydroxyurea remain the most widely used drugs for chronic phase. Intensive and non-intensive combination chemotherapy regimens have not produced significant improvement in survival. Interferon therapy is promising in patients who respond but requires further evaluation. Splenectomy does not improve survival but may be useful in selected circumstances. Extramedullary disease carries a poor prognosis and responds best to local treatment. The treatment of blast transformation is very difficult. The lymphoid variety should be recognised as response is better to appropriate treatment. Some Philadelphia (Ph) chromosome negative cases have disease which is probably identical to Ph positive disease and respond well to treatment. The others carry a very bad prognosis and respond poorly to treatment.

Lomustine, vindesine and bleomycin (LVB) used in the treatment of relapsed advanced Hodgkin's disease. A prospective study on behalf of the East of Scotland and Newcastle Lymphoma Group (ESNLG).

Sixty-three patients with relapsed advanced Hodgkin's disease were treated with lomustine (CCNU), vindesine and bleomycin (LVB). Age range was 17-72 years, with 38 males and 25 females. Thirty patients achieved complete remission (CR) with a median duration of 24+ months (range 3-55). Nineteen continue in unmaintained CR. CR rates were highest for those patients who relapsed greater than 6 months after first line treatment and for those at second or subsequent relapse. CR rates were higher in those with nodal only relapse. Twenty-seven patients were non-responders and six were partial responders. These 33 patients were subsequently changed to alternative chemotherapeutic regimes and 26 failed to respond to any therapy and have since died. Only one patient is in unmaintained complete remission. The regimen was well tolerated by patients, and easy to administer. It produced no serious episodes of toxicity. We conclude that LVB is of value in the management of relapsed advanced Hodgkin's disease especially in chronic relapsing patients, and where relapse occurs greater than 6 months after the first line treatment. We are presently unsure whether it offers any advantage over reintroduction of first line treatment in the latter group.

Methylprednisolone, etoposide, vindesine, and chlorambucil (PEEC) alone or alternating with CHOP as initial or salvage therapy for non-Hodgkin's lymphoma.

A novel cytotoxic drug combination, PEEC, has been tested in the initial or salvage treatment of lymphomas. The PEEC combination alone is active in high grade or intermediate grade NHL with two complete and two partial remissions out of four patients so treated. When combined with standard CHOP therapy using an alternating regime, seven out of 11 patients obtained a complete remission and four partial remission. Ten patients were well, off treatment, beyond one year from presentation. The combination was less impressive, however, as salvage therapy with two partial responses in a heavily pre-treated group of nine patients.

Oesophageal varices associated with busulphan-thioguanine combination therapy for chronic myeloid leukaemia.

5 patients receiving continuous busulphan and 6-thioguanine for chronic myeloid leukaemia (CML) were found to have oesophageal varices associated with abnormal liver function tests. 3 of these cases presented with gastrointestinal haemorrhage and 1 patient died. The 2 other cases had varices discovered at endoscopy. Nodular regenerative hyperplasia (NRH) of the liver was identified as the cause of portal hypertension in the 4 patients on whom liver biopsies were done. The administration of busulphan and thioguanine in combination is likely to be associated with the development of NRH, with portal hypertension and oesophageal varices occurring in a substantial proportion of cases.