Blood Res (2024) 59:6
Published online February 26, 2024
https://doi.org/10.1007/s44313-024-00003-z
© The Korean Society of Hematology
Correspondence to : Pankaj Malhotra
hematpgi@gmail.com
© The Author(s) 2024. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Background The standard dose (SD) of horse anti-thymocyte globulin (hATG) ATGAM (Pfizer, USA) or its biosimilar thymogam (Bharat Serum, India) for the treatment of Aplastic Anemia (AA) is 40 mg/kg/day for 4 days in combination with cyclosporine. Data on the impact of hATG dose on long-term outcomes are limited. Here, we describe our comparative experience using 25 mg/kg/day (low-dose [LD]) hATG for 4 days with SD for the treatment of AA.
Methods We retrospectively studied patients with AA (age > 12 years) who received two doses of hATG combined with cyclosporine. Among 93 AA patients who received hATG, 62 (66.7%) and 31 (33.3%) patients received LD and SD hATG with cyclosporine, respectively. Among these,seventeen(18.2%) patients also received eltrombopag with hATG and cyclosporine. Overall response rates [complete response (CR) and partial response (PR)] of LD and SD hATG groups at 3 months (50% vs. 48.4%; p = 0.88), 6 months (63.8% vs. 71.4%; p = 0.67), and 12 months (69.6% vs. 79.2%; p = 0.167) were comparable. The mean (Standard Deviation) 5-year Kaplan–Meier estimate of overall survival and event-free survival was 82.1 (4.6)% and 70.9 (5.5)% for the study population. The mean (standard deviation) 5-year Kaplan–Meier estimate of overall survival and event-free survival of those who received LD hATG versus SD hATG dose was 82.9 (5·3)% versus 74.8 (10·3)% (P = 0·439), and 75.2 (6.2)% versus 61.4(11.2)% (P = 0·441).
Conclusion Our study revealed that the response rates of patients with AA and LD were similar to those of patients with SD to hATG combined with cyclosporine in a real-world setting.
Keywords: Horse anti-thymocyte globulin, Dose, Aplastic anemia, Response
Blood Res 2024; 59():
Published online February 26, 2024 https://doi.org/10.1007/s44313-024-00003-z
Copyright © The Korean Society of Hematology.
Arihant Jain1†, Aditya Jandial1†, Thenmozhi Mani2, Kamal Kishore3, Charanpreet Singh1, Deepesh Lad1, Gaurav Prakash1, Alka Khadwal1, Reena Das4, Neelam Varma4, Subhash Varma4 and Pankaj Malhotra1*
1Department of Clinical Hematology and Medical Oncology, PGIMER, Chandigarh 160012, India
2Department of Biostatistics, CMC, Vellore, Hematology, India
3Department of Biostatistics, PGIMER, Chandigarh, India
4Department of Hematology, PGIMER, Chandigarh, India
Correspondence to:Pankaj Malhotra
hematpgi@gmail.com
© The Author(s) 2024. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Background The standard dose (SD) of horse anti-thymocyte globulin (hATG) ATGAM (Pfizer, USA) or its biosimilar thymogam (Bharat Serum, India) for the treatment of Aplastic Anemia (AA) is 40 mg/kg/day for 4 days in combination with cyclosporine. Data on the impact of hATG dose on long-term outcomes are limited. Here, we describe our comparative experience using 25 mg/kg/day (low-dose [LD]) hATG for 4 days with SD for the treatment of AA.
Methods We retrospectively studied patients with AA (age > 12 years) who received two doses of hATG combined with cyclosporine. Among 93 AA patients who received hATG, 62 (66.7%) and 31 (33.3%) patients received LD and SD hATG with cyclosporine, respectively. Among these,seventeen(18.2%) patients also received eltrombopag with hATG and cyclosporine. Overall response rates [complete response (CR) and partial response (PR)] of LD and SD hATG groups at 3 months (50% vs. 48.4%; p = 0.88), 6 months (63.8% vs. 71.4%; p = 0.67), and 12 months (69.6% vs. 79.2%; p = 0.167) were comparable. The mean (Standard Deviation) 5-year Kaplan–Meier estimate of overall survival and event-free survival was 82.1 (4.6)% and 70.9 (5.5)% for the study population. The mean (standard deviation) 5-year Kaplan–Meier estimate of overall survival and event-free survival of those who received LD hATG versus SD hATG dose was 82.9 (5·3)% versus 74.8 (10·3)% (P = 0·439), and 75.2 (6.2)% versus 61.4(11.2)% (P = 0·441).
Conclusion Our study revealed that the response rates of patients with AA and LD were similar to those of patients with SD to hATG combined with cyclosporine in a real-world setting.
Keywords: Horse anti-thymocyte globulin, Dose, Aplastic anemia, Response
Baseline characteristics of the study population.
Variable | Total patients (n = 93) | Low dose hATG (n = 62) | Standard dose hATG (n = 31) | P value |
---|---|---|---|---|
Age, mean ± SD | 33.4 ± 15.3 | 35.2 ± 15.5 | 29.7 ± 14.2 | |
Age ≤ 40 years n(%) | 62 (66.7) | 37 (59.7) | 25 (80.6) | 0.043 |
Age > 40 years n(%) | 31 (33.3) | 25 (40.3) | 6 (19.4) | |
Sex | ||||
Male n(%) | 60 (64.5) | 40 (64.5) | 20 (64.5) | 1.000 |
Female n(%) | 33 (35.5) | 22 (35.5) | 11 (35.5) | |
Symptom to diagnosis interval in months, median (IQR) | 3 (2,5) | 3 (2,5) | 3 (1.75, 5.25) | 0.713 |
Severity of AA | ||||
Severe AA n(%) | 87 (93.5) | 58 (93.5) | 29 (93.5) | 1.000 |
Very severe AA n(%) | 6 (6.5) | 4 (6.5) | 2 (6.5) | |
PNH clone | ||||
Positive n(%) | 33 (35.5) | 24 (38.7) | 9 (29.0) | 0.133 |
Negative n(%) | 41 (44.1) | 29 (46.8) | 12 (38.7) | |
Not available n(%) | 19 (20.4) | 9 (14.5) | 10 (32.3) | |
Prior red blood cell transfusion n(%) | 74 (79.6) | 48 (77.4) | 26 (83.9) | 0.467 |
Prior platelet transfusion requirement n(%) | 63 (67.7) | 41 (66.1) | 22 (71.0) | 0.638 |
Hematologic parameters | ||||
Hemoglobin (g/L), mean ± SD | 6.4 ± 1.9 | 6.4 ± 1.9 | 6.3 ± 1.9 | 0.909 |
TLC (× 109/L), mean ± SD | 2.6 ± 1.2 | 2.5 ± 1.2 | 2.8 ± 0.9 | 0.268 |
ANC (× 109/L), median (range) | 0.6 (0.3–1.1) | 0.6 (0.3–1.1) | 0.7 (0.3–1.3) | 0.481 |
ALC (× 109/L), median (range) | 1.5 ± 0.67 | 1.5 ± 0.64 | 1.8 ± 0.7 | 0.173 |
Platelet count (× 109/L), median (range) | 14 (8–2.2) | 13 (9–20) | 14 (7.8–23) | 0.671 |
Treatment characteristics of study population.
Variable | Total patients (n = 93) | Low dose ATG (n = 62) | Standard dose ATG (n = 31) | P value |
---|---|---|---|---|
Diagnosis to ATG interval (months, range) | 2 (1,5) | 2 (1,5) | 3 (1,6) | 0.957 |
Timing of hATG | ||||
As first-line, n(%) | 58 (62.4) | 37 (59.7) | 21 (67.7) | 0.449 |
As second-line, n(%) | 35 (37.6) | 25 (40.3) | 10 (32.3) | |
Eltromobpag with ATG | ||||
Yes, n(%) | 17 (18.3) | 12 (19.4) | 5 (16.1) | 0.704 |
No, n(%) | 76 (81.7) | 50 (80.6) | 26 (83.9) | |
Formulation of ATG | ||||
ATGAM | 51 (54.8) | 39 (62.9) | 12 (38.7) | 0.027 |
Thymogam | 42 (45.2) | 23 (37.1) | 19 (61.3) | |
Duration of IST after ATG (months), median (range) | 25 (12,47) | 25.5 (14.75,51.25) | 25 (9,34) | 0.072 |
Hematologic responses of the study population based on hATG dose.
Variable | Total patients (n = 93), n(%) | Low-dose ATG (n = 62), n(%) | Standard-dose ATG (n = 31), n(%) | P value |
---|---|---|---|---|
Overall response ( PR + CR) | ||||
At 3 months | 46/93 (49.5) | 31/62 (50) | 15/31 (48.4) | 0.883 |
At 6 months | 57/86 (66.3) | 37/58 (63.8) | 20/28 (71.4) | 0.483 |
At 12 months | 58/80 (72.5) | 39/56 (69.6) | 19/24 (79.2) | 0.382 |
Response at 3 months | ||||
CR | 5/93 (5.4) | 4/62 (6.5) | 1/31 (3.2) | 0.809 |
PR | 41/93 (44.1) | 27/62 (43.5) | 14/31 (45.2) | |
NR | 47/93 (50.5) | 31/62 (50.0) | 16/31 (51.6) | |
Response at 6 months | ||||
CR | 12/86 (14.0) | 8/58 (13.8) | 4/28 (14.3) | 0.813 |
PR | 45/86 (52.3) | 29/58 (50.0) | 16/28 (57.1) | |
NR | 29/86 (33.7) | 21/58 (36.2) | 8/28 (28.6) | |
Response at 12 months | ||||
CR | 16/80 (20.0) | 10/56 (17.9) | 6/24 (25.0) | 0.614 |
PR | 42/80 (52.5) | 29/56 (51.8) | 13/24 (54.2) | |
NR | 22/80 (27.5) | 17/56 (30.3) | 5/24 (20.8) | |
Best response | ||||
CR | 44/93 (47.3) | 28/62 (45.2) | 16/31 (51.6) | 0.813 |
PR | 28/93 (30.1) | 19/62 (30.6) | 9/31 (29.0) | |
NR | 21/93 (22.6) | 15/62 (24.2) | 6/31 (19.4) | |
CR after 12 months | 23/93 (24.7) | 15/62 (24.2) | 8/31 (25.8) | 0.865 |
Time to best response (months), median(IQR) | 10 (3–18) | 12 (3–18) | 6 (3–18) | 0.635 |
Relapse on IST | 11 (11.8) | 7 (11.3) | 4 (12.9) | 1.000 |
Time to relapse (months), median (IQR) | 44 (20–94.5) | 51.56 (24.75–88.75) | 35.0 (10–98) | 0.330 |
Clonal evolution | 2 (2.2) | 0 (0) | 2 (6.5) | 0.109 |
Generalized estimating equation analysis for respone to hATG over time.
Variables | OR(95%CI) | P value |
---|---|---|
Treatment arm | ||
Standard dose ATG | 1.28 (0.43–3.86) | 0.659 |
Low dose ATG | 1.00 | |
Time | 1.89 (1.26–2.84) | 0.002 |
Standard dose ATG x time | 0.81 (0.50–1.30) | 0.377 |
Low dose ATG x time | 1.00 |
Saurabh Shukla, Anil Kumar Tripathi, Shailendra Prasad Verma, Nidhi Awasthi
Blood Res 2020; 55(4): 193-199Chul Won Choi, Jun Ho Jang, Jin Seok Kim, Deog-Yeon Jo, Je-Hwan Lee, Sung-Hyun Kim, Yeo-Kyeoung Kim, Jong-Ho Won, Joo Seop Chung, Hawk Kim, Jae Hoon Lee, Min Kyoung Kim, Hyeon-Seok Eom, Shin Young Hyun, Jeong-A Kim, and Jong Wook Lee
Blood Res 2017; 52(3): 207-211Jin Ah Kim, Young Bae Choi, Eun Sang Yi, Ji Won Lee, Ki Woong Sung, Hong Hoe Koo, and Keon Hee Yoo
Blood Res 2016; 51(4): 256-260