MEI肿瘤研发再受挫 pracinostat临床二期研究宣告失败

肿瘤研发领域一直是生物医药领域最为火爆的研究领域，许多大大小小的生物医药公司都前仆后继的涌入这一领域希望发掘到一桶金。不过，残酷的是这其中的失败者永远比成功者多得多。最近，MEI医药公司就在第二次试图进入这一领域时再遇挫折。

根据最近MEI医药公司最新发布的消息，公司开发的pracinostat，一种HDAC inhibitor，在与Celgene公司的药物Vidaza联合治疗骨髓增生异常综合征的临床二期研究中未能达到预期终点。骨髓增生异常综合征是一种罕见的骨髓紊乱疾病，常见于肿瘤患者接受放化疗之后。在此次有约100名MDS患者参与的临床二期研究中，pracinostat与Vidaza联合治疗组未能够与Vidaza对照组在完全缓解率方面有显著性差异。同时，联合治疗组中患者还表现出疲劳、胃肠道毒性等方面的副作用，可谓是惨败。

不过，MEI公司显然并未放弃将pracinostat应用到肿瘤治疗领域中的计划。尽管此次临床二期研究表明pracinostat在治疗MDS方面并无作用，公司仍表示pracinostat在治疗急性粒细胞白血病方面可能会有意想不到的作用。在去年12月份时，MEI公司就曾公布了一项关于pracinostat治疗急性粒细胞白血病的早期先行实验，并得到了不俗的结果。目前公司正计划就此进一步展开研究。

如果此次研究再宣告失败，那么就将标志着MEI公司进军肿瘤药物研发领域的第二次失败。2010年，公司曾计划开发一种治疗卵巢癌药物phenoxodiol，最终宣告失败，并直接导致公司重组。想必MEI公司是抱着不成功便成仁的心态来推进其在肿瘤药物市场的计划。

详细英文报道：

MEI Pharma's ($MEIP) lead candidate failed to meet its primary goal in a Phase II study on myelodysplastic syndrome, a rare bone marrow disorder that often develops after cancer treatment, sending the biotech trawling for a positive spin on the data.

The company, formerly Marshall Edwards, tested a combination of its own pracinostat with Celgene's ($CELG) Vidaza in a placebo-controlled Phase II trial on 102 MDS sufferers. The addition of pracinostat made no difference in the rate of complete remission, the study's primary endpoint, compared with the older drug alone, MEI said, and the data on secondary goals aren't yet mature. On the safety side, fatigue, gastrointestinal toxicities and myelosuppresion were more common in the pracinostat arm and led to more frequent study dropouts, the company said.

The news sent MEI's shares down more than 60% on Monday morning.

Despite the failure, MEI isn't giving up on the effort, planning to unveil full results from the study at a scientific meeting this year and combing the results for silver linings. In the meantime, the company is holding off on any plans to start additional studies.

"While we are disappointed with these top-line response data, we are diligently analyzing the entire data set as well as subsets from this study," CEO Daniel Gold said in a statement. "Specifically, we are trying to fully assess the impacts of discontinuations on clinically important efficacy outcomes, including duration of response, event and progression-free survival and overall survival. These findings will be important to inform the future development path for pracinostat."

And even if pracinostat comes up short in MDS, the company believes its drug may have a future in acute myeloid leukemia (AML). At December's American Society of Hematology meeting, MEI reported early signs of positive results among 33 evaluable patients in a Phase II AML trial, and rates of response and survival have improved ever since, the company said. MEI plans to present data from all 50 enrolled patients at the European Hematology Association meeting in June.

Pracinostat is MEI's second chance at oncology development after the 2010 failure of phenoxodiol, an ovarian cancer treatment, tanked its share value and spurred an overhaul. The company regrouped with the help of some private investors in 2012 and in-licensed pracinostat, an HDAC inhibitor, from Singapore's S*Bio.