Khalil Ullah  ( Department of Haematology, Armed Forces Bone Marrow Transplant Centre, Rawalpindi, Pakistan. )
Parvez Ahmed  ( Department of Haematology, Armed Forces Bone Marrow Transplant Centre, Rawalpindi, Pakistan. )
Shahid Raza  ( Department of Haematology, Armed Forces Bone Marrow Transplant Centre, Rawalpindi, Pakistan. )
Tariq Mahmood Satti  ( Department of Haematology, Armed Forces Bone Marrow Transplant Centre, Rawalpindi, Pakistan. )
Qamar-un-Nisa Chaudhry  ( Department of Haematology, Armed Forces Bone Marrow Transplant Centre, Rawalpindi, Pakistan. )
Fahim Akhtar  ( Department of Haematology, Armed Forces Bone Marrow Transplant Centre, Rawalpindi, Pakistan. )
Muhammad Khalid Kamal  ( Department of Haematology, Armed Forces Bone Marrow Transplant Centre, Rawalpindi, Pakistan. )
Farrukh Mahmood Akhtar  ( Department of Haematology, Armed Forces Bone Marrow Transplant Centre, Rawalpindi, Pakistan. )
Badshah Khan  ( Department of Haematology, Armed Forces Bone Marrow Transplant Centre, Rawalpindi, Pakistan. )

Objective: To evaluate the outcome in denovo AML patients treated with different remission induction and consolidation chemotherapy regimens in our population.
Methods: A retrospective study on acute myeloid leukaemia (AML) patients was carried out at Armed Forces Bone Marrow Transplant Centre Rawalpindi Pakistan between July 2001 and June 2006. During 5 years period  46 patients received treatment for AML at our centre. Twenty nine patients were males and 17 were females. Median age of patients was 21 years (range: 7 -56 years). These 46 patients were categorized into two groups on the basis of type of leukaemia and chemotherapy given. In group-I 40 patients (group Ia: 23 patients of M1-M6, less M3 group Ib: 17 patients of AML M3) received anthracycline and cytarabin based chemotherapy. In group- II, six patients (AML- M3) received all trans retinoic acid (ATRA) based chemotherapy.
Results: In group Ia, out of 23 patients, 14 patients (60.8%) achieved complete remission (CR) after remission induction chemotherapy,10 patients remained in CR after 3rd and 4th consolidation. Eleven patients died and five patients relapsed during treatment and follow up. In this group overall CR, relapse rate (RR) and mortality was 30.4% (7/23), 21.7% (5/23) & 48% (11/23) respectively. In group Ib out of 17 patients, 9 patients (53%) achieved CR after remission induction. Eleven patients died during treatment while one patient relapsed in this group. Overall CR, RR & mortality was 29.4% (5/17), 6% (1/17) & 55% (11/17) respectively.  In group II all patients achieved CR (100%) after 1st course of chemotherapy. Two of these patients unfortunately died of uncontrolled sepsis during 1st consolidation, while remaining 4 patients 66.6% are on maintenance chemotherapy and are still in CR.
Conclusion: Overall CR, RR and mortality in all groups was 35% (16/46), 13% (6/46) and 52% (24/46) respectively at a median follow-up of 36 + 8 months. Survival in AML-M3 patients treated with ATRA based chemotherapy is significantly superior than anthracycline based chemotherapy (66.6% vs 29.4%). Infection and chemotherapy toxicity being major causes of mortality (JPMA 57:434:2007).

Acute Myeloid Leukemia (AML) is a heterogeneous, invariably fatal disease if untreated.¹ About 70% of AML patients present with cytogenetic
abnormalities, however the percentage of known genetic alterations is much lower.² Prognostic factors predicting treatment outcome include age, sex, performance status, white blood cell count, splenomegaly, presence or absence of bleeding or infection, time to achieve CR and AML subtype.^3,4
Remission induction therapy in AML is the most difficult phase in the management of these patients..^5,6 Current chemotherapy with advanced supportive care will enable 75% to 80% of AML patients to enter complete remission.⁷ Most patients with de novo AML achieve complete remission following induction therapy, however long term disease free survival is observed in only 25-50% of patients. The early mortality during remission induction phase has been reduced from the earlier figures of 20-30% to 10-15% in patients less than 60 years of age.^8,9
Acute promyelocytic leukemia (APL) accounts for 10-15% of denovo cases of AML in younger adults and is characterized by a reciprocal translocation that involves chromosomes 15 and 17. Remarkable progress has occurred in the treatment of patients with APL since the introduction of all-trans retinoic acid (ATRA). Targeted therapy with ATRA based chemotherapy results in an apparent cure in 70-80% of patients.^10-12 Both allogeneic and autologous  stem cell transplantation (allo & auto SCT) are effective in AML but their role in APL is not clear given the excellent outcome with ATRA based chemotherapy.¹³
Post-remission therapy in AML remains problematic. Once remission is induced, further intensive treatment of patients with AML is essential to prevent relapse. Three options are available for younger patients: Allo SCT (from an HLA-matched related or unrelated donor), auto SCT, or intensive consolidation chemotherapy (ICC). Results of ICC in adults patients with AML are similar to allo SCT in first remission..^14,15 However in children overall survival has been reported to be higher in allo SCT as compared to ICC and auto SCT.¹⁶ Extensive database analysis according to evidence based medicine (EBM) has highlighted the limitations observed in published studies concerning consolidation therapy in AML. These include emergence of genetics subgroups and biological heterogeneity of AML. New drugs targeting specific abnormalities could eventually become the cure of each specific subtypes with its peculiar biological, molecular and prognostic features.¹⁴ With this background, we are presenting our initial experience in the management of AML at Armed Forces Bone Marrow Transplant Centre (AFBMTC) Rawalpindi over a period of 5 years. The main objective of the study is to assess the response to different remission induction and intensification regimens used in the management of acute myeloid leukemia and long term outcome in these patients.
Patients and Methods
This retrospective study was carried out at Armed Forces Bone Marrow Transplant Centre, (AFBMTC) Rawalpindi, Pakistan between July 2001 and June 2006. All patients with  AML fulfilling the following eligibility criteria were included: all newly diagnosed cases of AML with an age less than 60 years and a good performance status.
The exclusion criteria were: patients older than 60 years of age, ECOG performance status > 2, multiple organ dysfunction with ALT more than twice the normal, creatinine more than normal, cardiac ejection fraction < 60%, pregnant and lactating females and patients having concurrent active malignancies
All patients were diagnosed and classified into AML subtypes on the basis of FAB  classification. Initially cytogenetic analysis was not a routine practice in our hospital however for the last 2 years. It is being done in all newly diagnosed cases of AML now. AML patients were categorized in two groups, group I (Ia and Ib) and Group II and chemotherapy was planned.
Criteria for the assessment of complete remission (CR) status were based on bone marrow examination showing <5% blasts, done at day+20 post chemotherapy or when ANC>1.0x109/L. Criteria for persistent disease were based on day+20 bone marrow examination findings; >20% blasts in a marrow having at least 20% cellularity. Minimal residual disease (MRD) status was assessed by fluorescent immunosorbant hybridization (FISH) / RT-PCR. Criteria for relapse status was > 20%  blasts in the marrow after achieving complete remission.

This retrospective study was carried out at Armed Forces Bone Marrow Transplant Centre, (AFBMTC) Rawalpindi, Pakistan between July 2001 and June 2006. All patients with  AML fulfilling the following eligibility criteria were included: all newly diagnosed cases of AML with an age less than 60 years and a good performance status.
The exclusion criteria were: patients older than 60 years of age, ECOG performance status > 2, multiple organ dysfunction with ALT more than twice the normal, creatinine more than normal, cardiac ejection fraction < 60%, pregnant and lactating females and patients having concurrent active malignancies
All patients were diagnosed and classified into AML subtypes on the basis of FAB  classification. Initially cytogenetic analysis was not a routine practice in our hospital however for the last 2 years. It is being done in all newly diagnosed cases of AML now. AML patients were categorized in two groups, group I (Ia and Ib) and Group II and chemotherapy was planned.
Criteria for the assessment of complete remission (CR) status were based on bone marrow examination showing <5% blasts, done at day+20 post chemotherapy or when ANC>1.0x109/L. Criteria for persistent disease were based on day+20 bone marrow examination findings; >20% blasts in a marrow having at least 20% cellularity. Minimal residual disease (MRD) status was assessed by fluorescent immunosorbant hybridization (FISH) / RT-PCR. Criteria for relapse status was > 20%  blasts in the marrow after achieving complete remission.

During this period of 5 years, a total of 53 newly diagnosed AML patients reported at AFBMTC, Rawalpindi

Table 1. Patient characteristics.

Age (years)
      < 20 Years       :   8
         21-40 Years  : 26
         41-60 Years  : 12
         Sex (Male/Female) : 29/17
FAB Classification 
         M1   :   4
         M2   : 16
         M3   : 23
         M4   :  2
         M5   :  1
Cytogenetics
         Normal Karyotype  :  5
         t (8:21)  :  7
         t (15:17)  : 14
         Not done  : 20

Table 2.

A. Anthracycline / cytarabine based remission induction and consolidation chemotherapy in AML
    Group Ia (n=23) and group Ib (n=17)
Induction
 Course 1:  Cytosine arabinoside 100mg/m2, 12 hourly, slow IV push day 1-10 (20doses)
   Daunorubicin 50mg/m2, slow IV push on day 1,3 & 5  (3 doses)
   Etoposide 100mg/m2, IV infusion over 1 hour, day 1-5 (5 doses)
   Consolidation
 Course 2:  Cytosine arabinoside 100mg/m2, 12 hourly, slow IV push day 1-8 (16 doses)
   Daunorubicin 50mg/m2 slow IV push on day 1,3 & 5  (3 doses)
   Etoposide 100mg/m2, IV infusion over 1 hour, day 1-5  (5 doses)
 Course 3:  Idarubicin 10mg/m2 slow IV push day 1,2,3 (3 doses)
   Cytosine arabinoside 100mg/m2, IV infusion over 2 hours, 12 hourly day1-5 (10 doses)
   Etoposide 100mg/m2, IV infusion over 01 hour, day 1-5 ( 5 doses)
 Course 4:  Mitozantrone 10mg/m2 slow IV push day 1-5 (5 doses)
   Cytosine arabinoside 1g/m2 IV infusion over 02 hours  12 hourly, day 1-3 ( 6 doses)
 Course 5:  Cytosine arabinoside 3g/m2, IV infusion over 04 hours 12 hourly on day 1,3 & 5 (6 doses)

B. ATRA based remission induction, consolidation and maintenance Chemotherapy in APL
                                          Group II (n=6)
Remission Induction
 Course 1:  Idarubicin 12mg/m2, I/V infusion over 30 mins  on day 2,4,6 & 8 (4 doses)
   All trans retinoic Acid (ATRA) 45mg/m2 till CR or day+90
Consolidation
 Course 2:  Idarubicin 5mg/m2/d days 1-4 (4 doses) Cytosine arabinoside 1g/m2 day 1-4 (4 doses)
   ATRA 45mg/m2/d PO days 1-15
 Course 3:  Mitozantrone 10mg/m2/d, I/V Infusion over 30 mins day 1-5 (5 doses)
   Etoposide 100mg/m2/d,  IV infusion Over 01 hour, 12 hours after Mitozantrone days 1-5, (5 doses)

 Course 4:  Idarubicin 12mg/m2/d, I/V day-1 (1 dose)
   Cytosine arabinoside 150mg/m2 IV 8 hourly on (Days 1-5) (15 doses)
   6-Thioguanine PO, 70mg/m2/8 hourly Days 1-5

Maintenance (for 2 years)  ATRA 45mg/m2/d for  15 days every 3 months
   Methotrexate 15mg/m2 , weekly P.O
   6-Mercaptopurine 50mg/m2, daily PO

for management. Out of these 7 patients were lost to follow up during different stages of treatment, so these were excluded from the study. Of the remaining 46 patients included in study, 29 were male and 17 were female. Eight patients were < 20 years of age, 26 were between 21-40 years of age and 12 were between 41-60 years of age. Subtypes in these patients were, M1 (n=4), M2 (n= 16), M3 (n= 23), M4 (n=2) and M5 (n=1) as shown in Table 1. These 46 patients were divided into 2 groups: group I&II depending on subtype of leukaemia and type of chemotherapy given. Group 1 was further subdivided into group Ia and Ib. Group Ia included 23 patients with  AML M1-M6 less AML M3 and  group Ib included 17 patients with AML M3. Group 1a and 1b received anthracycline based chemotherapy. Group II included 6 patients with AML-M3, who received ATRA based chemotherapy as shown in Table 2.
In-group Ia, 14 patients achieved CR after remission induction chemotherapy, 13 patients remained in CR after 1st consolidation, 11 patients maintained CR

                   Table 3. Outcome of patients in different sub-groups.

Newly Diagnosed AML
(n=46)

after 2nd consolidation and 10 patients remained in CR after 3rd and 4th consolidation. Eleven patients died during treatment. Five patients relapsed during treatment and follow up in this group. Two patients relapsed during consolidation chemotherapy. One patient relapsed within 6 months of completion of chemotherapy and two patients relapsed between 6 months and 1 year of chemotherapy. In group Ib out of 17 patients, 9 achieved CR after remission induction. Eleven patients died during treatment. One patient relapsed after 3rd consolidation. Five patients are still in CR and being followed-up.  In group II out of six patients, all achieved CR after 1st course of chemotherapy. Two of these patients unfortunately died of uncontrolled sepsis during 1st consolidation, while remaining 4 patients are on maintenance chemotherapy and are still in CR.
A total of 46 patients received chemotherapy for acute myeloid leukemia. Of these 34.8% (16/46) in all groups are still in CR at the end of 5 years with 30% CR in group I (Ia = 30.4%, Ib = 29.4%) and 66.6% CR in group II patients. Overall outcome in different subgroups in shown in Table 3. Major causes of mortality were infections and chemotherapy induced toxicity.  Infective causes of mortality were septicemia and DIC (11/24) and pneumonia (5/24) while non infective chemotherapy related causes of mortality were ARDS (3/24), acute renal failure (2/24), hepatotoxicity (2/24) and toxic ileus (1/24).

Management of AML has two major goals: to induce complete haematological remission by cytoreductive chemotherapy and thereafter to prevent leukaemia relapse. In most of the centers induction regimens consist of anthracycline and cytarabine in conventional doses, producing a CR rate of 60-70%.17 In our study 63% (29/46) patients achieved CR after remission induction chemotherapy.
Post remission treatment is not uniform in AML patients. Three options are available once the patient achieves remission; intensive consolidation chemotherapy (ICC), allogeneic stem cell transplantation (allo SCT) and autologous stem cell transplantation (auto SCT).18 Allo SCT remains the treatment of choice for children/ adolescents as well as adults with AML in remission, when matched related donors are available. For all others there is no advantage of auto SCT over ICC.19 Wood WG et al20 reported 60%, 48% and 53% disease free survival (DFS) in children after allo SCT, auto SCT and ICC respectively. Castaigne S et al21 reported 44%, 44% and 40% DFS in adults at 4 years after allo SCT, auto SCT and ICC respectively. Similarly Tracey A et al16 observed higher DFS after allo SCT as compared to auto SCT (79-63%) in children in consective trials from Australia and New Zealand. Classical consolidation chemotherapy provides 8-40% 5 years disease free survival (DFS) in AML.22 In our study at the end of 5 years DFS was 34.8% after ICC at a median followup of 36 + 8 months. None of our patients was subjected to either auto SCT or allo SCT.
Treatment of acute promyelocyte leukaemia (APL) with allcis tran retinoic acid (ATRA) and Arsenic trioxide has become more rationale resulting in high cure and salvage rates.23 Fenaux P et al24 reported 80% event-free survival (EFS) in the ATRA group compared with 50-55% in anthracycline based chemotherapy arm.23 In our study 66.6% DFS was absorved in AML-M3 patients who received ATRA based chemotherapy as compared to 29% DFS in AML-M3 patients who received anthracycline based chemotherapy. ATRA was not easily available in Pakistan initially when we started treating APL patients but for the last 2 years it is freely available. Therefore now all newly diagnosed APL patients in our centres receive ATRA based chemotherapy. Although the number of patients who received ATRA based chemotherapy is small and at this stage it would not be realistic to predict the outcome and comparison of results in these two subgroups of APL. As the number of patients increase with longer duration of follow-up, outcome of APL with or without ATRA would be better analyzed. Better strategies to control and treat infections will further improve our results considerably in future.

Critical analysis of our results in AML show high mortality during remission induction. More than 50% of our patients died during induction and majority of these deaths were due to infections despite close liaison with microbiologists and targeted antimicrobial therapy as per our laid down protocol. In conclusion overall CR rate of 34.8% in AML at 5 years in our study is quite encouraging. However patients with AML-M3 who were treated with ATRA based chemotherapy achieved better disease free survival as compared to those AML-M3 who received anthracycline based chemotherapy. Better strategies to control and treat infection will further improve our results. Newer antifungals and antivirals are not easily available as these drugs are not registered in our country. The availability of these drugs at economical rates will be a break through in the management of infections in AML patients.

1. Lowenberg B, Downing JR, Burnett A. Acute Myeloid Leukemia. N Engl J Med. 1999; 341: 1051-62.
2. Pompetti F, Spadano A, Pilla D, Persichitti L, Formaro A, Fioritoni G et al. Molecular alerations in acute myeloid leukemia; Analysis of 90 unselected consecutive patients in a single center in Pescara Italy. Blood 2001; 98:192 b.
3. Zittoun R, Cadiou M, Bayle C. Prognostic value of cytologic parameters in acute myelogenous leukemia. Cancer 1984; 53:1526-32.
4. NC Gorin, E Stey, RJ Jones, HI Levitsky, I Borrello, S Slavin. New developments in the therapy of Acute Myelocytic Leukemia. Hematology Am Soc Hematol Educ Program. 2000;69-89.
5. Stone RM, O'Donnell MR, Sekeres MA. Acute myeloid leukemia. Hematology. Am Soc Hematol Educ Program 2004; 98:117.
6. Trickett AE, Manobaran A, Kwan YL, Brighton TA, Case J. Leukemia cell viability in AML patients treated with standard or low dose chemotherapy. Blood 2001; 98:196 b.
7. Kolitz JE. Current therapeutic strategies for acute myeloid leukaemia. Br J Haematol. 2006; 134: 555-72.
8. Levi I, Grotto I, Yerushalmi R, Bassat IB, Shpilberg O. Meta analysis of Autologous Bone Marrow Transplantation (ASCT) vs chemotherapy in adult patients with AML in first remission. Leuk Res 2004; 28: 605-12.
9. Estey E, Thall P, Andreeff M, Beran M, Kantarjian H, O'Brien S, et al. Use of granulocyte colony-stimulating factor before, during, and after fludarabine plus cytarabine induction therapy of newly diagnosed acute myelogenous leukemia or myelodysplastic syndromes; comparison with fludarabine plus cytarabine without granulocyte colony-stimulating factor. J Clin Oncol 1994; 12: 671-8.
10. Grimwade D. The pathogenesis of acute promyelocytic leukaemia: evaluation of the role of molecular diagnosis and monitoring in the management of the disease. Br J Haematol 1999;106:591-613.
11. Lowenberg B, Griffin JD, Tallman MS. Acute myeloid leukemia and acute promyelocytic leukemia. Hematology. Am Soc Hematol Educ Program 2003; 82-101.
12. Mochiduki Y, Muramoto S. Therapy-related acute promyelocytic leukemia with a t(9;22) (q34;q11) and t(15;17) (q22;q11 to approximately 12) subclone]. Rinsho Ketsueki 2005;46: 1218-22.
 13. Nabhan C, Mehta J, Tallman MS. The role of bone marrow transplantation in acute promyelocytic leukemia. Bone Marrow Transplantation 2001;28:219-26.
14. Visani G, Olivieri A, Malagola M, Brunori M, Piccaluga PP, Capelli D. Consolidation therapy for adult acute myeloid leukemia: A systematic analysis according to evidence based medicine. Leuk Lymphoma. 2006;47: 1091-102.
15. Harousseau JL, Cahn JY, Pignon B, Witz F, Milpied N, Delain M. Comparison of autologous bone marrow transplantation and intensive chemotherapy as postremission therapy in adult acute myeloid leukemia. Blood 1997;90: 2978-86.
16. Tracey A, Brien O, Russel SJ, Vowels MR, Oswald CM, Tiedemann K. Results of consecutive trials for children newly diagnosed with acute myeloid leukemia from the Australian and new Zealand Children's Cancer Study Group. Blood 2002;100: 2708-16.
17. Wiernik PH, Banks PL, Case DC, Arlin ZA, Perimax PO, Todd MB et al. Cytarabine plus idarubicin or daunorubicin as induction and consolidation therapy for previously untreated adult patients with acute myeloid leukemia. Blood 1992; 79:313-19.
 18. Fagioli F, Bacigalupo A, Frassoni F, Van Lint MT, Occhini D, Gualadi F, et al. Allogeneic bone marrow transplantation for acute myeloid leukemia in first complete remission: the effect of FAB classification and GVHD prophylaxis. Bone Marrow Transplantation 1994;13:247-52.
19. Woods WG, Kobrinsky N, Buckley JD. Timed-sequential induction therapy improves postremission outcome in acute myeloid leukemia: a report from the Children's Cancer Group. Blood 1999; 87:4979-89.
20. Woods WG, Neudorf S, Gold S, Sanders J, Buckley JD, Barnard DR. A comparison of allogeneic bone marrow transplantation, autologous bone marrow transplantation, and aggressive chemotherapy in children with acute myeloid leukemia in remission: a report from the children's Cancer Group. Blood 2001;97:56-62.
21. Castaigne S, Chevret S, Archimbaud E, Fenaux P, Bordessoule D, Tilly H et al. Randomized comparison of double induction and timedsequential induction to a "3+7" induction in adults with AML: long-term analysis of the Acute Leukemia French Association (ALFA) 9000 study.Blood 2004;104: 2467-74.
22. Geller RB, Saral R, Karp JE, Santos GW, Burke PJ. Cure of acute myelocytic leukemia  in adults: a reality. Leukemia 1990;4:313-5.
23. Song KW, Lipton J. Is it appropriate to offer allogeneic hematopoietic stem cell transplantation to patients with primary refractory acute myeloid leukemia. Bone Marrow Transplantation 2005; 36:183-91.
24. Fenaux P, Chevret S, Guerci A, Fegveux N, Dombret H, Thoma X et al. Long-term follow-up confirms the benefit of all-trans retinoic acid in acute promyelocytic leukemia. European APL 91Group. Leukemia 2000;8:1371-7.