7/27/2019 Randomized Comparison of Busulfan and Hydroxyurea in Chronic http://slidepdf.com/reader/full/randomized-comparison-of-busulfan-and-hydroxyurea-in-chronic 1/11 1993 82: 398-407 Heinze and A Georgii R Hehlmann, H Heimpel, J Hasford, HJ Kolb, H Pralle, DK Hossfeld, W Queisser, H Loffler, B German CML Study Group myelogenous leukemia: prolongation of survival by hydroxyurea. The Randomized comparison of busulfan and hydroxyurea in chronic http://bloodjournal.hematologylibrary.org/site/misc/rights.xhtml#repub_requests Information about reproducing this article in parts or in its entirety may be found online at: http://bloodjournal.hematologylibrary.org/site/misc/rights.xhtml#reprints Information about ordering reprints may be found online at: http://bloodjournal.hematologylibrary.org/site/subscriptions/index.xhtml Information about subscriptions and ASH membership may be found online at: reserved. Copyright 2011 by The American Society of Hematology; all rights 900, Washington DC 20036. weekly by the American Society of Hematology, 2021 L St, NW, Suite Blood (print ISSN 0006-4971, online ISSN 1528-0020), is published For personal use only. by guest on December 11, 2012. bloodjournal.hematologylibrary.org From
11
Embed
Randomized Comparison of Busulfan and Hydroxyurea in Chronic
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
7/27/2019 Randomized Comparison of Busulfan and Hydroxyurea in Chronic
Heinze and A GeorgiiR Hehlmann, H Heimpel, J Hasford, HJ Kolb, H Pralle, DK Hossfeld, W Queisser, H Loffler, BGerman CML Study Groupmyelogenous leukemia: prolongation of survival by hydroxyurea. TheRandomized comparison of busulfan and hydroxyurea in chronic
http://bloodjournal.hematologylibrary.org/site/misc/rights.xhtml#repub_requestsInformation about reproducing this article in parts or in its entirety may be found online at:
http://bloodjournal.hematologylibrary.org/site/misc/rights.xhtml#reprintsInformation about ordering reprints may be found online at:
http://bloodjournal.hematologylibrary.org/site/subscriptions/index.xhtmlInformation about subscriptions and ASH membership may be found online at:
reserved.Copyright 2011 by The American Society of Hematology; all rights900, Washington DC 20036.weekly by the American Society of Hematology, 2021 L St, NW, SuiteBlood (print ISSN 0006-4971, online ISSN 1528-0020), is published
For personal use only.by guest on December 11, 2012. bloodjournal.hematologylibrary.orgFrom
Randomized Compar i son o f Busu l fan and Hydroxyurea in Chron icM y e l o g e n o u s L e u k e m i a : P r o lo n g a ti o n of Surv iva l by Hydroxyurea
By R. Hehlmann, H. Heimpel, J . Hasford, H.J . Kolb, H. P ralle, D.K. Hossfeld, W . QueiBer, H. Lbffler, B.Heinze, A. G eorgii,
P .v. Wussow, C. Bartram, M . GrieBhammer, L. Bergmann, U. Essers, C. Falge, A. Hochhaus, U. QueiBer, C. Sick,
P. Meyer, N. Schmitz, K. Verpoort, H. Eimermacher, F. Walther, M. Westerhausen, U.R. Kleeberg, A. Heilein,
A. Kabisch. C. Barz, R . Zimmermann, G. Meuret, A . Tichelli, W.E . Berdel, L. Kanz, B. Anger, F. J . Tigges, L. Schmid,
W . Brockhaus, R. Zankovich, U. Schlafer, 1. WeiBenfels, K. Mainzer, A. Tobler, M . Perker, J . Hohnloser,
D. Messener, J . Thiele, T. Buhr, H. Ansari, and the German CML Study Group
In a randomized multi center study the influence of hydrox-
yurea versus busul fan on the duration of th e chronic phase
and on survival of chronic myelogenous leukemia (CML)
was determined. In addition cross resistance and adversereactions of the drugs were analyzed. From July 1 983 t o
January 19 91, 441 CML patients were randomized to re-ceive hydroxyureaor busul fan. Of these, 90.7% were Phila-
delphia positive; 25.7% were low, 38.2% intermediate,and 36.2% high risk patients according to Sokal‘s score.
The median survival of the busulfan treated Philadelphia-
positive patients is 45. 4 months and of t he hydroxyurea
group 58 .2 months (P =.008) . The surv ival advantage for
th e hydroxyurea treated patients is recognized in all riskgroups. Sixty four patients reached therapy resis tance be-
RUG THER APY of chronic myelogenous leukemia
D CML ) has basically been palliative until now , withthe d rug of choice being busulfan for the past 40 years. Little
prolongation of life has been observed since the report by
Minot et al in 1924.’ Curative therapy can be offered only to
those 10% o 20% of CM L pa tients of sufficiently young age,
who have an HLA compatible, related or unrelated, bone
marrow donor.’z3 Median survival of CML patients from
the time of diagnosis varied between 30 and 55 months,
depending less on the mode of therapy than on patient se-
lection and exclusion of high risk patients such as Philadel-phia-negative or preblastic ones.4
Busulfan, an alkylating agent active a t the stem cell level,
is known to control CML-related signs and symptoms in
95% of patients for at least 3 months.’ All studies have
shown its efficacy and reliability since its introduction in
1953. Controlled com parison with a n um ber of single
agents, radiotherapy, a nd w ith intensive combination ther-apy has show n its superiority w ith regard to efficacy, adversereactions, and/ or duratio n of disease control.”” Th e me-
From Klin ikum Man nheim , Universitat Heidelberg, Man nheim ,
Submitted December 21 , 1992; accepted February 25 , 1993.
The study was initiated by the Sueddeutsche Haemoblastose-
gruppe and is supported by the German Bundesminister fuer
Forschung und Technologie, Foerderkennzeichen 01Z W044,
01ZP900I -01ZP90019, an d 01Z W8503.
Address reprint requests to R. Hehlmann, MD , I I I . Medizinische
Klinik, Kliniku m M annh eim der Universitiit Heidelberg, Wiesba-denerstr. 7-11, 6800 Mannheim , Germany.
The publication C O SIS of this article were defiayed i n part by page
charge payment. This article must therefore be hereby m arked
“advertisement” in accordance with 18 U.S.C.section 1734 solely to
indicate this act.
Deutschland.
0 9 9 3 by T he American Society of Hematology.
0006-4971/93/8202-0031$3.00/0
fore blast crisis and were crossed over to the alternative
drug. The 23 patients wi th primary hydroxyurea had a me-
dian survival of 5.6 years, the 41 patients with primary
busulfan herapy a median survivalof 2.7 years (P = .02).
Adverse reactions were less frequent w ith hydroxyurea
wi th no severe adverse effects (lung fibrosis, long lasting
bone marrow aplasia). The analysis of white blood cell
counts in the course of tr eatment showed lower counts in
the hydroxyurea patients. We conclude that hydroxyurea
is superior to busulfan n therapy of CML in chronic phase
and should be used as firs t li ne therapy. Busulfan may have
a role as secondary herapy after hydroxyurea resistance or
intolerance.0 993b y The American Society of Hematology.
dian (or mean) survival times of busulfan-treated CM L pa-
tients range from 35 to 47 m ont hs4
More recently, hydroxyurea, an inh ibitor oft he ribonucle-
otide reductase, became increasingly popular because of its
rapid action and low level of adverse effects.” Some retro-
spective studies on small series of patients ind icated a sur-
vival advantage of hydro xyurea-treated patients,12-” which,
however, was never substantiated by a controlled study. As
early as 1972, Kenne dy” reported in a retrospective study
on 20 patients with unknown Philadelphia chromosome
status that hydroxyurea controlled all CML-related symp-tom s as well as busulfan. Hydroxy urea did not prevent pro-
gression to blast crisis, but the investigator felt that it could
prolong the duratio n of the chronic phase as compared withbusulfan. The median duration of response to hydroxyureawas 41 months for 10not pretreated patients and 8 months
for 10 pretreated and busulfan-resistant patients. Schwar-zenberg et al, in a study of 43 patients who were treated withhydroxyurea, leukapheresis, and splenectomy, reported
that survival was similar to that after busulfan therapy,l3Schwarz and Canellos14 reated 35 patients, m ostly resistant
to busulfan an d/o r in accelerated phase, with hydroxyureaan d had good results. Bolin et all5 reported th e results of a
retrospective study on 30 busulfan- and 14 hydroxyurea-treated patients. Expected median survival was 48 monthsand >90 months for the busulfan and the hydroxyureagroups, respectively. However, this difference was not signif-icant due to the small sample size.
In 1983, the Ge rma n CM L study group, therefore, de-cided to compare in a randomized study the influence ofhydroxyurea versus busulfan on t he dur atio n of the chronicphase and on survival of CML. Further goals of the studywere the examination of cross resistance of hydroxyurea
and busulfan and the determination of duratio n of efficacyafter cross over; the dev elopment of a prognostic score onthe basis of prospectively docum ente d parameters of possi-ble significance for the prognosis of CM L; the com parison
398 Blood, VOI82, NO 2 (J uly 15). 1993: p 398-407
For personal use only.by guest on December 11, 2012. bloodjournal.hematologylibrary.orgFrom
1Patients enteredin the intcntion-to-treat analysis
HU BU
2 1 216
Hu BU5 7
Drop&t Death Alive
(censored)
HU BU
52 55
(event) (censored)
HU BU Hu BU85 107 Q 54
4
Death after
dropout
Hu BU
12 8
Fig 2. Flow diagr am of r andomiz e d pat ie n t s .
the presence ofrapidly rising WBC coun ts (cell doublin gin less than
2 months) low dose continuo us busulfan therapy was acceptable.
Hydroxyurea was administered a t an initial dosage of 40 mg/kg/
d. Th e initial dosage was reduced in the presence of thromboc yto-
penia (<100X IO 9 platelets/L). Control ofthe blood counts initially
was three times weekly due to the rapid action of hydroxyurea.When the WBC count dropped to below 20 X 109/L the hydrox-
yurea dosage was reduced to 20 mg/kg/d. This dosage was then
adapted individually. If WBC counts rose above 20 X 109/L, thedosage was increased. The dosage was reduced, if the WBC count
dropped below I O X 109/L,and was interrupted, if the WBC count
was below 5 X IO’/L. Therap eutic goal was a normal W BC coun t
(range 5 to 15 x lo9&).
Documentation, At diagnosis and randomization all data were
documented in an initial docum entation form. During the course
of the study docume ntation forms were completed every 6 months.
Whenever a checkpoint was reached (see study outline) a separate
checkpoint form was filed. After a patient had died or was lost tofollow up (including bone marrow transplantation), a final docu-
mentation form was filed. Adverse events were documented ac-cording to WH O grading.
Sample size estimation was done according toGeorge and Desu.” Assuming 01 = 0.05 (two-sided) and 6 =0.20,388 patients (1 94 per group) w ere necessary to detect a relative riskof at least 1.42 in the med ian survival time in favo r of hydroxyurea.
The randomization lists were computed according to Efronl’stratified for participating h ospitals. After getting informed consent
suitable patients were randomized centrally by phone by the Bio-metric Center for Therapeutic Studies.
Five interim analyses were performed as planned in the trial pro-
tocol. The probability for type I error 01 was adjusted followingOB rie n and Fleming,’’ safeguarding an overall error probability <
Biostatistics.
0.05. The required 01 for the final analysis was 0.04009. Th e analy-ses followed the intention-to-treat strategy. Survival was analyzed
with the Kaplan-Meier estimator an d logrank test.20 Analyses for
prognostic factors were performed with Cox proportional hazards
regression model.2’ The calculation of risk groups was performed
with the equation ? Score = exp. [0.0116 (age, 43.4) + 0.0345
(spleen size, 7.51) + 0.0188 ((pla te le t~ /700 )~ 0.563) +0.0887
(peripheral blasts, 2. IO)]. All analyses were performed by the Bio-
metric Cen ter with th e program package SAS.’’The protocol followed the declaration of Helsinki an d
was approved by the ethics committees o f the Universities of M u-
nich and U lm. Informed consent w as obtained from all patients.
RESULTS
Initial patients’ characteristics. The initial characteris-
tics of the 44 1 randomized and documented CML patients
are shown in Table 1 according to treatment group and
Philadelphia (Ph) status. The Ph status was known for 409
patients of which 37 1 (90.7%) were Ph positive ( 187 in the
hydroxyurea, 184 in the busulfan arm). All patients are
shown including the nine patients who were not in chronic
Ethics.
T a b l e 1. C M L Initial P a t i e n t s ’ C h a r a c t e r i s t i cs
BU HU P h f
(n=216) (n=225) (n=371)
Age (vr )
Sex (% male)
Fatigue, general ill feeling (%)
Symptom s due to organomegaly (%)
Weight loss (%)
Fever (%)
Karnofsky index (%)
Splenomegaly (%)Hepatomegaly (%)
Spleen size in cm below cost al margin
Liver size in cm in MCL
Extramedullary manifestatio ns
(skin, lymp hnodes)(%)
Ph-positive (%)*
Additional cy togenetic aberrations (%)
Platelets x 109/L
Hemoglobin (g/dL)
LDH (U/L)
Circulating blast s (%)
Circulating prom yelocy tes (%)
Basophils (%)
Reticulocytes (%o)
Erythroblasts (per 100 WBC)
ALP (index)’
BM blasts (%)tBM promyelocytes (%)t
Grouping int o risk groups (Ph+ only)*
WBCx IO=L
Lo w (%)
Intermediate (%)
High (%I
50.2
60.7
69
37
24
9.4
87.1
72.2
54.6
6. 4
12.9
9
91.5
1 1
161.9
454.3
12.2
725
2.9
4. 5
4. 5
23.0
1 .1
15.2
4. 1
10.1
25.3
41.6
33.1
49.2
52
59
34.7
20.7
4. 5
88.7
72.4
46.6
6. 3
12.6
3.6
89.9
12.9
156.6
488.4
11.9
72 0
3.4
4.5
4.5
23.7
0.9
16.0
4.4
10.7
26.0
35.0
39.0
47.8
58.8
64
36
19
7
88.2
71.9
49.2
6.5
12.6
6
100
9. 8
169.1
493.9
12.1
749
3.1
4.7
4. 9
23.3
1 .o15.5
3.9
10.1
25.7
38.2
36.2
All features not specified as otherwise were recor ded n 95% to 100%
Features recorded n 93% (cytogenetics)an d 80% ALP) of pat ients.
t Features recorded n 74% of cases.
t Features recorded in 92.5%o f Ph+ patients.
of pat ients.
For personal use only.by guest on December 11, 2012. bloodjournal.hematologylibrary.orgFrom
busulfan therapy was 20 months, that of secondary hydrox-
yurea therapy I I .7 months. Eleven patients progressed to
blast crisis within 1 m ont h after crossover (four in the group
with primary hydroxyurea therapy, seven in the group with
primary busulfan therap y). Because of secondary resistance
before blast crisis (checkpoint 2) interferon alpha was addedin seven cases (four busulfan patients, three hydroxyurea
patients), othe r chemotherapy (arabinosylcytosin, mitomy -
cin, thioguanin) in 10 patients (five in each therapy group).
It is evident from Fig 7 that secondary busulfan after hy-
droxyurea resistance has an additional im pact on survival.
There is a survival advantage for primary hydroxyurea an dsecondary busulfan in all subgroups of Table 2. Most nota-
bly, patients with cytopenia and/or bone marrow aplasia,who carry a poor prognosis, are only found in the primary
busulfan group. But even w ithout the 16 cytopenic patients,
the survival difference between the treatm ent groups after
crossover is significant (P= .01).
Once blast crisis has developed no survival difference is
observed between the treatment groups (data not shown).
Cytogenetic response rates. Fo ur patients in the hydrox-
yurea arm and two patients in the busulfan arm showed
cytogenetic responses (redu ction of Ph-po sitive cells by 10%
to 100%)during the course oftherapy corresponding to 3%
and 2% of the evaluable patients. O ne complete cytogeneticremission was observed in a hydroxyurea treated case. Someof the responses may be du e to additional therapy added tothe monotherapy later on when secondary resistance was
observed (checkpoint 2) (the on e case with a com plete cyto-genetic remission also had polychemotherapy, ano ther casealso had interferon alpha).
Data were available from 20 9 patientstreated with hydroxyurea and from 204 patients treatedwith busulfan. T he frequency of adverse effects is lower withhydroxyurea tha n with busulfan ( 1 5. 8 vs 24.2 symptoms per100 patient years). Most impo rtantly, serious adverse effectssuch as long lasting bone marrow aplasia or lung fibrosiswere virtually not observed in the hydroxyurea arm (one
Adverse effects.
Fig 5. Duration of chronic
phase (time from diagnosis to
resistance to randomized ther-
years apy or blast crisis).
transient event under hydroxyurea vs 13 events in the bu-
sulfan arm). This low toxicity may have facilitated a possi-
bly mo re intensive treatm ent with hydroxyurea.
Since one rea-
son for the difference of survival might be a difference in
disease control, we analyzed the WBC cou nts in both grou ps
during the first 24 mon ths of treatment. After 18 and 24
months 43 % and 34% of the hydroxyurea-treated, but only
11 % an d 16% of the busulfan-treated patients h ad norm alWBC counts, respectively. In the hydroxyurea group pa-
tients with normal WBC counts had a survival advantage
compared with those with elevated counts (P<.06).
Correlationof survival with WBC counts.
DISCUSSION
Th e most im port ant observation in this study is the signifi-
cantly better median survival of the patients treated with
hydroxyurea as compared w ith those treated with busulfan.
This result confirms som e reports of a possible survival ad-
vantage by hydroxyurea in small, uncontrolled
but the m agnitude of the survival advantage cam e as a sur-prise. Th e result raises several biologic as well as therapeutic
questions.First, the question has to be addressed whether hydrox-
yurea prolongs the survival of CML patients or whether
busulfan therapy was suboptimal. Th e median survival tim eof 45.4 mo nths with busulfan com pares well with an earliercontrolled study that finds a median survival of busulfan-treated CML patients of 44 months.6 In addition, it has to beexcluded that the survival difference is due to an unequaldistribution of prognostic factors. In Table 1 we show thatthe relevant prognostic parameters as well as the distribu-tion of risk groups did not favor the hydroxyurea group.
There were more hydroxyurea patients in the high riskgroup (39% vs 33%),although this was no t significant. Wetherefore conc lude tha t the survival difference is the resultof the different therapies.
Second, the apparent prolongation of survival of the hy-droxyurea group is contrary to so me earlier notions on pro-
For personal use only.by guest on December 11, 2012. bloodjournal.hematologylibrary.orgFrom
0 1 2 3 4 5- rimary hydroxyurea (n =23). median survival 2.45 years
__ _._
rimary busulfan (n =41), median survival0.9years
p =0.002
0 . 6 -
0 . 5 :
0 . 4 -
0 . 3 :
0 . 2 -4 L........................
.__,LI............................. I....I
Fig 7. Survival after cross-
8 7 , I . , ' 1 I - * * 8 r r I 8 8 " 1 , I " ' I ' 9 I r l - rm-mq- over of therapy (checkpoint 1).
7 8 (A) Survival from diagnosis; (B )
years survival from crossover.0 1 2 3 4 5 6
gression of CM L that the course of CM L is determined by
intrinsic factors rather th an This has to be ana-
lyzed also in the context o fth e good survival data with inter-
feron alpha (our unpublished On e inter-
pretation would be tha t a decrease of tumo r mass and/or a
slowing of granulocyte proliferation rate decreases the pro-gression rate to blast crisis. The hypothesis would be th at thenumber of clonal cells in the mitotic pool correlates withlikelihood of blastic transformation implying that the less
tumor burden and proliferation are present the less likelyblastic transformation might occur. Th is hypothesis is sup-ported by the observation of Kolitz e t a129 tha t intensivehydroxyurea therapy induces cytogenetic responses in nineof 14 patients of 25% to 100%and that th e level of bonemarrow hypocellularity correlates with cytogenetic re-
sponse. If this hypothesis is true, the more efficient reduc-tion of WBC counts, which probably reflect tumor cellmass, by hydroxyurea m ight in part acco unt for the survivaladvantage.
Therefore, if there is a correlation between tumor mass
and probability of blastic transformation, a m ore efficient
reduction of WBC counts by the c omb ination of suitable
antiproliferative drugs might result in a further prolonga-
tion of survival in CM L (eg, hydroxyurea and interferon
alpha as in our ongoing randomized CM L study I1 or combi-nations wi th arab in osy lcy t~ sine ) .~~In this context, the question has to be addressed why in-
tensive combination chemo therapy did not show prolonga-tion of survival as observed w ith h y d r o x y ~ r e a . ~ ~ ' ~ ~ ~ ' ~ ~ ~hegoal of these studies, however, primarily w as cure of CML
by the intensive approach and not continuous control ofmyeloproliferation over extended periods of tim e as in ou r
study.Finally, the high mutagenic potential of busulfan with
subsequent promotion of acute leukemia as observed inpolycythemia verag3 as to be considered. Although the me-dian survival time of the busulfan-treated patients of morethan 45 months is longer than that of historic controls of
For personal use only.by guest on December 11, 2012. bloodjournal.hematologylibrary.orgFrom
Table 2. Reasons for, and Survival After , Crossoverof Therapy
Before Blast Crisis
Patients (mean survival
after crossover in years)
Primary Primary
Reasons or Crossov er Busulfan Hydroxy urea C
Progressive thro mbocyto sis ' lO(1.8) 8(2.6) 18
Resistance with progression of disease 9 (0.4) 9 (2.1) 18
Resistance with progression of disease
and cytopenia and/or b one marrow
aplasia 16 (0.7) - 16
Various reasonst 6(1.7) 6(2.4) 12
c 41 (1.0) 23 (2.2) 64
Platelets of in general m ore than 1million/pL or rapidly rising plate-
lets above ca. 700.000/pL in spite of intensific ationof therapy (doubling
of initial dose).
t Intolerable adverse reactio ns ( 5 ) .primary (a priori) drug resis tance
(3). ecision of patients (2),BMT ( I ) ,unknown ( 1 ) .
untreated CML patients,' or of CML patients treated withsplenic irradiation,'.' it cannot be excluded that its muta-
genic effect has a negative impact on survival, which be-
comes visible, if busulfan is compared with hydroxyurea.
A third observation of interest is the apparent gain of
survival time by secondary busulfan after primary hydrox-
yurea therapy. Although the number of patients qualifying
for an adequate trial with secondary busulfan is small (n =
19, 8.4% of hydroxyurea-treated patients), the survival ad-
vantage is significant and adds to the survival advantage of
the hydroxyurea arm described in this report. Busulfan
turned out t o be inferior to hydroxyurea as first line therapy,
but apparently plays a role after hydroxyurea resistance.One reason for the poor success of secondary hydroxyurea
treatment after primary busulfan seems to be the high num-
ber of patients with cytopenias and/or bone marrow aplasia
after busulfan therapy, which was not observed after pri-
mary hydroxyurea therapy. This agrees well with the known
toxicity pattern of busulfan.24 t appears that in the presenceof busulfan-induced cytopenias hydroxyurea cannot add
any survival advantage.
We cannot entirely exclude that our survival results are
influenced by an earlier diagnosis than in previous eras. Our
inclusion criteria for randomization and therapy, however,excluded patients who were very early in the course of dis-
ease. In addition, the percentage of our patients in the low-risk group is in contrast to Sokal's patient^'^.^^ lower than
that in the intermediate- and high-risk groups. This distri-bution argues against the possibility that our favorable sur-
vival results are due t o a high number of low-risk patients orearlier diagnosis.
Since all parameters included in this report have beendocumented prospectively under the same mandatory mo-
dalities, the patient sample is well suited for the generationof a prognostic score (score 1) based on prospectively col-lected parameters35 as well as a detailed histomorphologiccharacterization of CML according to Ph status and clinicalcourse, which is ongoing.
We conclude that hydroxyurea is superior to busulfan in
therapy of CML in chronic phase and should be used as first
line therapy. Busulfan may, however, have a role as second
line treatment after hydroxyurea resistance or intolerance.The importance of the reduction of WBC in the chronic
phase for prolongation of survival in CML, irrespective of
the cytostatic drug used, will be analyzed further within on-
going randomized studies.
ACKNOWLEDGMENT
The assistance of Dr A. Kiittel, B. Knichel, M. Dumke, and G.
Krankenhaus Berlin-Neukolln; Hamatologisches Zentralla-bor der Universitiit, Inselspital Bern; V. Med. Klinik desKlinikums Niirnberg; Stadt. Krankenhaus Kaiserslautern,Med. Klinik D 6, Kaiserslautern; Zentrum Innere Medizin,Abt. f. Himostaseologie, Klinikum Niirnberg; Klinik f. In-
nere Medizin, Onkologie/Hamatologie, Stildt. KlinikenOldenburg; Kinderklinik und Poliklinik, Universitats
klinikum Rudolf Virchow, Berlin; KreiskrankenhausFussen; Innere Abteilung, Luisenkrankenhaus, Lindenfels/
For personal use only.by guest on December 11, 2012. bloodjournal.hematologylibrary.orgFrom
Singer J, Stewart PS, Storb RF, Sullivan KM, Tesler MC, Wither-spoon RP, Thomas E D Marrow transplantation from unrelated
donors for trea tme nt of hematologic malignancies: Effects of mis-
matching for one HLA locus. Blood 8 1 249, 1993
4. Heh lmann R : Cytostatic therapy in chronic myelogenous leu-
kemia: Review and perspectives, in Hu hn D, Hellriegel KP, Nie-
derle N (eds): Chron ic Myelocytic Leukemia an d Interferon . Berlin,
Germ any, Springer Verlag, 1988, p 102
5. Hau t A, Abbott WS, Wintrobe MM , Cartwright GE: Busulfan
in the treatmen t of chronic myelocytic leukemia: Th e effect of long
term intermittent therapy. Blood 17: , I9 6 1
6. Canellos GP, Young RC, Nieman PE, DeVita VT, Jr: Dibro-momannitol in the treatm ent of chronic granulocytic leukemia: A
prospective randomize d com parison w ith busulfan. Blood 45: 197,1975
7. Medical Research Council’s Working Party for Therapeutic
Trials in Leukemia: Chronic granulocytic leukemia: Comparisonof radiotherapy and busulfan therapy. Br Med J (Clin Res) 1:201,
19688. Cunningham I, Gee T, Dowling M, Chaganti R, Bailey R,
Hopfan S, Bowden L, Tur nbu ll A, Knap per W, Clarkson B: Results
oftreatm ent of Ph’+ chronic myelogenous leukemia with an inten-sive treatment regimen (L-5 protocol). Blood 53:375, 1979
9. Go to T, Nishikori M, Arlin Z, Gee T, Kempin S, Burchenal J,Strife A, Wisniewski D, Lambek C, Little C, Jhanwar S, ChagantiR, Clarkson B: Growth characteristics of leukemic and normal he-
matopoietic cells in Ph ’+ chronic myelogenous leukemia and ef-
20. Kalbfleisch JD , Prentice R L Th e Statistical Analysis of Fail-
ure Time Data. New York, NY, W iley, 1980
2 I . Cox D R: Regression models an d life-tables (with discussion).J Roy Stat SOC 4: 187, 1972
22. Sokal JE, Cox EB, Baccarani M, Tura S, Gomez C A, Robert-
son JE, Tso CY, Braun TJ, Clarkson BD, Cervantes F, Rozm an C,
the Italian Cooperative CML Study Group: Prognostic discrimina-
tion in “good-risk’’ chronic granulocy tic leukem ia. Blood 63:789,
1984
23. SAS Institute Inc: SAS/STAT User’s Guide, version 6 ,
fourth ed, vol 1. Cary, NC, SAS Institute, 198 9,94 324. Galton DAG: Chemotherapy of chronic myelocytic leuke-
mia. Semin Hematol 6:323, 1969
25. Sokal JE: Evaluation of survival data for chronic myelocyticleukemia. Am J Hematol 1:493, 1976
26. Talpaz M, Kantarjian H , Kurzrock R, Trujillo JM, Gutte r-
man JU: Interferon alpha produces sustained cytogenetic responsesin chronic myelogenous leukemia. Ann In tern Med 1145 32, 1991
27. Alimena G , Morra E, Lazzarino M, Liberati AM, Montefu-sco E. Inverardi D, Bernasconi P, Man cini M, Do nti E, Grignani F,
Bernasconi C, Dianzani F, Mandelli F Interferon alpha-2b as ther-apy for Ph’-positive chronic myelogenous leukemia: A study of 82patients treated with intermittent or daily administration. Blood
72:642, 198828. Thaler J, Kiihr T, Gastl G, Huber H , Duba C, Kemmler G ,
Gattringer C, Fluckinger T, Niedenvieser D, Seewann H , Abbre-dens K, Lang A, Gadner H, Fereberger W, Schiller I, Hausman-inger H, W eitgasser R, Michlmayr G,Fridrik M, H uber C: Rekom-
For personal use only.by guest on December 11, 2012. bloodjournal.hematologylibrary.orgFrom