hahawa 2010-6-5 00:59
ESA類藥物使用於癌症並不符經濟效益 且使用正在減少
作者：Zosia Chustecka
出處：WebMD醫學新聞
May 18, 2010 — 作者寫到，另一項經濟效益分析結果發現，使用紅血球生成刺激藥物（ESAs）治療癌症患者的貧血是不符經濟效益的，即使當該模式僅考慮保守使用這些藥物時，也就是遵循目前的指引建議，這些藥物僅使用於化學治療引起的貧血，且維持在特定的血紅素範圍之間。
作者們表示，沒有證據顯示ESA在這些病患身上比其他任何處理方式更具經濟上的優勢。
他們在線上發表於4月19日癌症期刊的文章中表示，目前的證據顯示，使用ESAs治療與癌症相關的貧血並不代表在金錢上有很好的價值。
主要作者愛德蒙頓亞伯特大學的Scott Klarenbach醫師表示，鐘擺已經遠離使用這些藥物，且廣泛使用這些藥物的熱情已經降低。
他指出，越來越多人知道使用ESAs可能的壞處，不只是對癌症族群（據報增加死亡率），還有慢性腎臟疾病與末期腎臟疾病患者。目前並不清楚使用這些藥物是否像傳說中「顯著正面地」提升生活品質。
他向Medscape腫瘤學表示，這些問題，還有潛在的藥品取得費用，已經讓我們對於這些藥物的價值提出更多疑問。
根據一項刊登在5月5日國家癌症機構期刊的新聞短訊，當第一個有關使用這些藥物的壞處警訊出現後，從2006年後期到2007年初期，使用ESAs的數量已經顯著減少。
該新聞短訊寫到，在最近美國食品藥物管理局進行的ESAs使用於癌症患者風險評估與減輕策略後，現在預期使用量會更進一步地降低。這委任腫瘤科醫師的訓練需要每三年重複一次，且提供詳細資訊與知情同意書給患者。預估這些方法將會減少這些藥物的使用，而增加以輸血治療貧血的需求。
Klarenbach醫師表示，我對於這個計劃的詳細內容並不清楚，但是我將會強烈同意對於癌症患者非常謹慎地使用這些藥物。
他表示，這裡還有一些值得我們學習的。他強調，在廣泛使用例如ESA這樣的藥物前，應該進行大型臨床研究來評估好處與傷害。
他表示，為了要確保有限的健康照護資源以最適當的方式來改善我們病患的預後，廣泛使用前進行經濟效益評估也是很重要的。
【經濟效益評估】
他們的經濟效益評估是，Klarenbach醫師與其同事們研發了一個以加拿大公眾健康照護系統為基礎的模式，並根據最近一項系統性綜論（CMAJ. 2009;180:E62-E71）結果鍵入數據。
作者們報告，相較於僅支持性地輸血，傳統ESA治療與15週內每單位品質校正生命年（QALY）費用增加267,000元美金有關。當他們校正這些分析，且納入有關於生活品質的多項假設後，都是偏向ESA，最低的QALY增加所需費用為126,000元美金。
他們接著進行了更多的場景分析，以模擬遵循最新美國臨床腫瘤醫學會（ASCO）與美國血液腫瘤醫學會（ASH）指引使用ESA，這兩個醫學會建議僅對於癌症病患因化學治療引起的貧血（非癌症本身引起的貧血）使用ESAs，且他們也設立了起始與目標血紅素值。
作者們表示，這是第一個考慮更保守地使用ESAs的分析。
當他們根據ASCO/ASH指引使用ESA時，結果是「數量上較低」，但是在所有分析中，每QALY類用增加超過70,000元美金，某些病例甚至超過100,000元美金。
他們的結論是，整體來說，這些發現代表更保守地使用與劑量，當以一般可接受的經濟吸引力標準時，ESA治療對於癌症患者仍然無法在經濟效益上吸引人。
【比較對象為輸血】
Klarenbach醫師表示，這項研究的比較對象是需要時輸血；因此，經濟效益比值是與標準照護相比。病患的費用，例如病患到達健康照護中心所花費的時間，以及旅途的費用，並未納到這些分析中，但是這些已經在其他研究中報告過。
他附帶表示，其他研究已經報告過付費意願低於1000元美金。有鑑於我們發現每QALY費用非常的高，正式結合這相對有限的病患付費意願，對於整體結論將沒有太有意義的影響。
作者們也表示，他們的經濟效益分析考慮到適合輸血的病患。他們也指出，仍然有特定亞族群是不容易接受輸血的（例如鐵質過量患者）或無法接受的（例如耶和華見證會會員），以及對於到健康照護中心接受輸血可能是個問題的患者。
研究者們表示沒有相關資金上的往來。
ESAs Not Cost-Effective in Cancer, and Use Is Declining
By Zosia Chustecka
Medscape Medical News
May 18, 2010 — Another economic evaluation has found that the use of erythropoiesis-stimulating agents (ESAs) for anemia in cancer patients is not cost-effective, even when the model considers only the more conservative uses of these agents, following the current guideline recommendation that they only be used for chemotherapy-induced anemia and within specified hemoglobin targets.
"There is no evidence to suggest that ESA is more economically attractive in this subgroup than in any other," say the authors.
Using ESA to treat anemia related to cancer does not represent good value for money.
"Available evidence suggests that using ESA to treat anemia related to cancer does not represent good value for money," they conclude in a paper published online April?19 in Cancer.
The pendulum is swinging away from the use of these agents, with "less enthusiasm for widespread use," said lead author Scott Klarenbach, MD, assistant professor at the University of Alberta in Edmonton.
"There is increasing awareness of the harms of ESAs," he said, not only in populations with cancer (where an increase in mortality has been reported), but also in populations with chronic kidney disease and end-stage renal disease. It is also not clear whether the purported increases in quality of life associated with these agents are "strikingly positive," he added.
"These issues, in addition to the substantial drug-acquisition costs, have led to more questioning about the value of these agents," he told Medscape Oncology.
There has been a marked decline in the use of ESAs in cancer since late?2006/early?2007, when the first alerts about harm appeared, according to a news brief in the May?5 issue of the Journal of the National Cancer Institute (2010;102;592-593).
A further decline in use is now expected, after the recent implementation of a risk evaluation and mitigation strategy by the US Food and Drug Administration for the use of ESAs in cancer patients. This mandates training for oncologists that needs to be repeated every 3 years and provides detailed information and informed-consent forms for patients. It is expected that both of these measures will decrease the use of these agents and increase reliance on blood transfusions to treat anemia instead, the news brief notes.
"I'm not familiar with the details of this program, but I would strongly agree with very careful use of these medications in the cancer population," Dr. Klarenbach said.
There are also lessons to be learned here, he suggested. Large-scale clinical trials to evaluate benefit and harm should be conducted "prior to widespread use of medications such as ESAs," he emphasized.
"It is also important to conduct cost-effectiveness evaluations prior to widespread use, in order to ensure that finite healthcare resources are used in the most appropriate manner to improve outcomes for our patients," he said.
Cost-Effectiveness Analysis
For their economic evaluation, Dr. Klarenbach and colleagues created a decision model based on the Canadian public healthcare system, and input data from a recent systematic review (CMAJ. 2009;180:E62-E71).
The authors report that, compared with supportive transfusions only, conventional ESA treatment was associated with an incremental cost per quality-adjusted life-year (QALY) gained of $267,000 during a 15-week time frame. When they adjusted these analyses and included multiple assumptions about quality of life, all favoring ESA, the lowest incremental cost per QALY gained was $126,000.
They then performed additional scenario analyses to simulate the use of ESA in accordance with the latest guidelines from the American Society of Clinical Oncology (ASCO) and the American Society of Hematology (ASH), which recommend that ESAs be used only for the treatment of chemotherapy-induced anemia in cancer patients (and not anemia associated with the cancer itself); they also specify initial and target hemoglobin levels.
This is the first such analysis to consider this more conservative use of ESAs, the authors note.
When they considered ESA use according to the ASCO/ASH guidelines, the results were "quantitatively lower," but in all the analyses, the incremental cost per QALY gained exceeded $70,000, and in many cases exceeded $100,000.
"Overall, these findings suggest that even with the more conservative administration and dosing, ESA therapy for patients with cancer is unlikely to be economically attractive when using a commonly accepted threshold of economic attractiveness," they conclude.
Comparator Was Blood Transfusions
The comparator in this study was blood transfusions as required; thus, the cost-effectiveness ratio is relative to this standard of care, said Dr. Klarenbach. Costs to the patients, such as the time taken and the cost incurred in traveling to a health center for a blood transfusion, were not included in this analysis, he explained, but this has been looked at in other studies.
"The willingness to pay that has been reported in other studies is less than $1000. Given the very high cost per QALY we found, formal incorporation of this relatively limited patient willingness to pay would have no meaningful impact on overall conclusions," he added.
The authors note that their economic analysis considered patients who were candidates for blood transfusions. They also point out that there are specific subpopulations in whom blood transfusions are difficult (e.g., patients with iron overload) or unacceptable (e.g., Jehovah's Witnesses), and that access to health centers that perform transfusions could pose problems.
The researchers have disclosed no relevant financial relationships.
Cancer. Published online April?19, 2010.