作者：Zosia Chustecka
出處：WebMD醫學新聞
December 9, 2008 (舊金山) — 德國研究者報告一項首次進行的全球隨機研究時表示，治療性血小板輸注是安全可行的，且可以降低費用。不過，此研究只包括171名病患，專家認為在做出安全性與運用的定論前需要更多資料。
這項試驗由德國紐倫堡Klinikum Nuremberg Nord的Hannes Wandt醫師發表於美國血液學會(ASH)第50屆年會暨展覽會中，研究對象是最近接受高劑量化療、全身放射線治療或者自體幹細胞移植治療各種血液惡性病，如多發性骨髓瘤、非何杰金氏淋巴瘤、何杰金氏症與急性骨髓性白血病的患者。
這類病患通常會發生血小板減少，目前的實務是，當血小板計數低於10,000/uL時，以預防性血小板輸注治療這些病患；Wandt醫師等人比較了此一標準實務與治療性血小板輸注這兩種方法，後者為病患發生臨床相關出血時才進行輸注(比淤血或微量黏膜出血更嚴重時)。
這個新策略顯著降低了需要的血小板輸注數量— 從預防組的152單位降低到治療組的118單位，減少率為27% (P?= .004)。Wandt醫師報告指出，預防組有14例達到啟動輸血的臨界值，但是未輸血；如果把這些也納入，減少率更高(33%)。
此外，Wandt醫師建議，藉由治療策略，46%的病患不需要血小板輸注，幾乎是預防組(22%)的兩倍。
本研究中治療組減少的血小板輸注數量可以換算成龐大的費用節省。Wandt醫師估計，如果把這策略運用到接受自體移植的病患，根據歐美這類病患的官方統計資料，粗估每年可以省下16,460單位的分離術血小板，也就是每年可以省下800萬歐元或者1,000至1,100萬美元。
【治療組發生比較多出血事件】
Wandt醫師表示，治療組比預防組發生比較多的臨床相關出血事例，分別是37%與7%，但這屬於預期發生的效應。他表示，所有的出血事件都是輕微到中度(等級2或3)且都使用輸血加以安全的治療。
Wandt醫師表示，雖然出血事件增加，但這些是啟動輸血的設定，若遵照此策略就得接受它。不過，沒有嚴重的致命出血。
兩組在住院、輸紅血球、白血球減少等沒有差異；相對的，治療組的血小板減少期間(指血小板數量 ≦20,000/uL)明顯比預防組長(平均值分別為5 天與3天；P= .004)，Wandt醫師表示，這也是預料中的。
Wandt醫師向與會聽眾表示，我們結論是，治療性血小板輸注對於自體幹細胞移植病患有經濟效益且是安全的；他指出，儘管會有比較多的微量出血，但都可以用血小板輸血安全地控制，防止發生嚴重出血。
不過，聽眾裡有許多醫師對「此一策略是安全」的結論進行爭論，認為研究病患數太少，難以偵測出兩組之間嚴重出血的差異。
Wandt醫師回應表示，強調本研究中沒有嚴重致命的出血事件，在他們之前發表的140名自體幹細胞移植病患的研究中也沒有嚴重事件(Bone Marrow Transplant. 2006;37;387-392)。他的團隊目前正對急性骨髓性白血病患者進行一個小型隨機試驗，所以很快就有更多資料。
但是，他也指出，目前為止的病患數的確太少，而無法偵測出嚴重出血的差異，這類差異也可能相當小。他的團隊之前估算，此一差異需要每一組有2,000名病患的臨床試驗才可以獲得。
ASH現任總裁、加州大學聖地牙哥分校醫學教授Kenneth Kaushansky醫師在被邀請對此治療性血小板輸注策略提出評論時表示，這很有趣，但是要改變臨床實務則為時尚早；我們需要更多資料。
華盛頓Puget Sound血液中心的血小板輸血專家Sherrill Slichter醫師同意需要更多資料，特別是不同的病患族群。在她的經驗中，有最多資料的是自體移植組，這一組的出血發生率比其他組低。她指出，在她於此會議所發表的PLADO研究(Medscape Oncology已經報導)中，自體移植病患有54%的出血率，而化療病患有68%、異體移植病患有72%。她表示，期待看到Wandt醫師可望於明年ASH會議中發表的有關急性骨髓性白血病患者的研究結果。
本研究接受德國癌症基因會贊助資金。 Wandt醫師宣稱沒有相關資金上的往來。
美國血液學會(American Society of Hematology (ASH))第50屆年會暨展覽會：摘要286發表於2008年12月8日。
ASH 2008: Therapeutic Instead of Prophylactic Platelet Transfusions Are Feasible and Reduce Costs
By Zosia Chustecka
Medscape Medical News
December 9, 2008 (San Francisco, California) — Therapeutic instead of prophylactic platelet transfusions are safe, feasible, and would reduce costs considerably, say German researchers reporting the first worldwide randomized study comparing the 2 different strategies. However, the study was conducted in 171 patients, and experts believe more data are needed before conclusions can be drawn about safety and the new strategy is implemented.
The trial was presented here at the American Society of Hematology (ASH) 50th Annual Meeting and Exposition by Hannes Wandt, MD, from the Klinikum Nuremberg Nord, in Nuremberg, Germany. It was conducted in patients who had recently received high-dose chemotherapy, total-body irradiation, or autologous stem-cell transplant for a variety of hematological malignancies, including multiple myeloma, non-Hodgkin's lymphoma, Hodgkin's disease, and acute myeloid leukemia.
Such patients often become thrombocytopenic. Current practice is to treat patients with prophylactic platelet transfusions, which are triggered when the platelet count falls below 10,000/uL. Dr. Wandt and colleagues compared this standard practice to an experimental strategy of therapeutic platelet transfusions, where patients received a transfusion only when they experienced a clinically relevant bleed (more than petechias or minimal mucosal bleeding).
This new strategy significantly reduced the number of platelet transfusions that were administered — from 152 in the prophylactic group to 118 in the therapeutic group, a reduction of 27% (P?= .004). There were 14 instances in the prophylactic group where the trigger was reached but a transfusion was not given; if these are included, the reduction is even greater (33%), Dr. Wandt reported.
In addition, with the therapeutic strategy, 46% of patients did not need a platelet transfusion, which is nearly double the 22% in the prophylactic group, Dr. Wandt commented.
The reduction in platelet transfusions seen in the therapeutic group of this study could translate into huge cost savings. Dr. Wandt estimated that if this strategy was implemented only for patients who receive autologous transplants, based on figures from official registries of such patients in the United States and Europe, an estimated 16,460 apheresis platelet units could be saved each year. This translates to cost savings of €8?million or $10?million to $11?million each year.
More Bleeding Episodes in Therapeutic Group
There were more instances of clinically relevant bleeding in the therapeutic group than in the prophylactic group (37% vs 7%), although this is to be expected with a strategy that has bleeding as the trigger for transfusion, Dr. Wandt commented. "All of the bleeding events were of minor to moderate severity (grade?2 or 3) and were safely treated with transfusions," he said.
"It is clear that bleeding episodes are increased, but these are triggers for transfusion, and if you follow this strategy, you have to accept this," Dr. Wandt commented. However, there were no severe or fatal bleeds, he added.
There was no difference between the 2 groups in hospitalization, number of red-blood-cell units transfused, or leukocytopenia. In contrast, the duration of thrombocytopenia (platelet count of ?20,000/uL) was significantly longer in the therapeutic-transfusion group than in the prophylactic group (median of 5 days vs 3 days; P?= .004), as would be expected with this strategy, Dr. Wandt commented.
"We conclude that our therapeutic platelet-transfusion strategy is cost effective and safe in patients after autologous stem-cell transplantation," Dr. Wandt told the meeting. Despite more minor hemorrhages with the experimental strategy than with the traditional prophylactic strategy, all bleeding events could be safely controlled by consecutive platelet transfusion, and development of major bleeding could be prevented, he added.
However, several clinicians in the audience took issue with the conclusion that this strategy was safe, saying that the patient numbers were too small to detect a difference in severe bleeding between the 2 groups.
Dr. Wandt countered by emphasizing that no major life-threatening bleeds were seen in this study, nor in a previous study that his group conducted in 140 patients with autologous stem-cell transplants (Bone Marrow Transplant. 2006;37;387-392). His group is currently conducting a similar randomized trial in patients with acute myeloid leukemia, so more data will be available soon.
But he did acknowledge that the patient numbers so far may be too small to detect a difference in severe bleeds, and he pointed out that such a difference may be extremely small. His group previously calculated that to detect such a difference, a clinical trial would need to have 2000 patients in each group.
Asked to comment on this therapeutic platelet-transfusion strategy, current ASH president Kenneth Kaushansky, MD, professor of medicine at the University of California, San Diego, said that this was interesting but it was too early to change clinical practice. "We need more data," he said.
Sherrill Slichter, MD, an expert on platelet transfusions from the Puget Sound Blood Center, in Seattle, Washington, agreed that more data are needed, particularly in different patient populations. The group for which there are the most data is autologous transplants and, in her experience, this subgroup has a lower incidence of bleeding than other groups. She noted that in the PLADO study that she presented at the meeting, already reported by Medscape Oncology, patients who received autologous transplants had a 54% rate of bleeding, compared with 68% in patients who received chemotherapy, and 72% in patients who received an allogeneic transplant. She said it will be interesting to see results from the ongoing study in acute myeloid leukemia patients, which Dr. Wandt hopes to present at the ASH meeting next year.
The study was funded by a grant from the German Cancer Foundation. Dr. Wandt has disclosed no relevant financial relationships.
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American Society of Hematology (ASH) 50th Annual Meeting and Exposition: Abstract 286. Presented December 8, 2008.
[ 本帖最後由 goodcat1111 於 2008-12-23 10:22 編輯 ] |
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