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Oxigene治疗卵巢癌临床二期研究结果遭质疑

2014-11-18 10:19:56 来源:生物谷

2014年11月15日讯 /生物谷BIOON/ --作为生物医药公司,其研发工作可以说是公司的核心命脉。每一次临床研究的成功与失败都直接牵动着公司未来的发展状况。最近著名的癌症药物研发公司Oxigene公司开发的卵巢癌药物fosbretabulin临床二期研究数据显示积极,然而这也未能给公司带来广泛的赞扬。

在这项研究中,研究人员招募了包括铂敏感和抗铂类型在内的共计107名患者。结果显示,fosbretabulin与Avastin联用将患者的平均无进展生存期由单独使用Avastin的4.8个月延长至7.3个月;这一结果体现在27名抗铂卵巢癌患者组时表现为3.4个月延长至6.7个月。获得了这一结果的Oxigene公司高兴地表示公司正在进行进一步临床三期研究计划的设计。

乍一看上去,这一结果表明fosbretabulin与Avastin联用能够很好的延长患者的生存期。然而,分析人士却认为这一结果或许并不像看上去的那样美好。

他们指出,Oxigene公司的这一设计思路的问题在于Avastin的选择上。众所周知,Avastin治疗卵巢癌的研究正在处于后期研究和审核的阶段,FDA并不一定会批准其作为治疗这一肿瘤类型的药物。其次是,随着目前肿瘤治疗方案的发展,许多药物都会选择和化疗用药结合使用,而一旦Avastin与化疗药物联合用药的方案被FDA批准为治疗卵巢癌的标准方案,势必将增大Oxigene公司的fosbretabulin与Avastin的研究成本和获批难度。因为Oxigene公司必须向FDA证明其方案要优于前者。这些问题无形中给fosbretabulin的研究工作额外增添了许多困难。

受此评论的影响,Oxigene公司的股价也应声下跌了10%,反映出投资者对公司研发前景的担忧。

详细英文报道:

Shares of South San Francisco-based Oxigene ($OXGN) slumped this morning, dropping 10% in the wake of its analysis of a Phase II study of its experimental therapy for tough-to-treat cases of ovarian cancer. The data for fosbretabulin overall were positive, putting the company on the road to a pivotal Phase III study. But an analysis from Adam Feuerstein at TheStreet may have taken the wind out of its sails.

First, the numbers:

Investigators say that they tracked promising results in the midstage study, which recruited 107 patients with platinum-sensitive as well as platinum-resistant ovarian cancer. Combined with Avastin, the drug achieved a median progress-free survival rate--where the disease did not worsen--of 7.3 months compared to 4.8 months for Avastin alone. In a post hoc subgroup analysis involving 27 platinum-resistant patients (the toughest ones to treat) there was an even better outcome: 6.7 months of PFS versus 3.4 months in the Avastin-only arm.

"We believe that these compelling data show fosbretabulin has a meaningful benefit in recurrent ovarian cancer, particularly in platinum-resistant patients who have extremely limited treatment options," said Dai Chaplin, Oxigene's president and CEO. "We now look forward to discussing these findings with the regulatory agencies to determine a potential path forward for fosbretabulin in ovarian cancer."

Here's where it ran into trouble, notes Feuerstein, an analyst who's done a considerable amount of work in the cancer field. A decision on using Avastin for ovarian cancer is looming, but hasn't arrived yet--complicating any analysis of a combination drug study like this. Avastin, by the way, achieved a solid PFS but not a statistically significant overall survival benefit for ovarian cancer patients, which may not prevent its approval.

If Avastin plus chemo becomes the standard of care in this area, then Oxigene will face some big challenges in designing a Phase III trial, notes Feuerstein. If the biotech decides to run a non-inferiority study, it will need a big and expensive patient population to examine. If it tries to beat Avastin/chemo, it faces a very tall order. And if Avastin is rejected, that makes Oxigene's task even more difficult.

Perhaps, suggests Feuerstein, the company should go a different route and try a combination with Votrient.

Investors, looking at the complications, evidently didn't see any easy answers this morning. And with its share price down today, Oxigene's execs will be challenged to provide some answers.

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