2015年2月4日讯 /生物谷BIOON/ --制药巨头百特公司最近表示将取消其对Onconova公司抗癌药物rigosertib欧洲临床研究的支持。这也意味着两家公司此前达成的价值5亿6千5百万美元的协议宣告打水漂。
Onconova公司的抗癌药物rigosertib被设计用于治疗骨髓增生异常综合征，这种骨髓异常紊乱疾病是一种常见的肿瘤药物治疗并发症。百特于2012年和Onconova公司签订协议，同意预付5千万美元外加高达5亿1千5百万美元的里程碑奖金交换rigosertib的欧洲市场版权。然而，两年过去了，经过一系列临床研究的失败，百特公司最终丧失耐性，决定放弃开展关于rigosertib的新研究以及申报rigosertib治疗低风险骨髓增生异常综合征的方案。
不过，Onconova公司透露，百特公司并不是彻底放弃了rigosertib。双方在rigosertib治疗高风险骨髓增生异常综合征和胰腺癌方面仍将保持密切合作。不过，去年Onconova公司在美国的一项关于治疗高风险骨髓增生异常综合征的临床研究中未能与对照组表现出显着性差异，使得投资者对rigosertib的预期再度走低不少。新年伊始，百特公司的这一决定对Onconova可谓是雪上加霜。
目前临床治疗肿瘤的各种疗法总存在着这样或那样的副作用或并发症。而骨髓增生异常综合征则是其中很常见的一种。然而，无论是美国市场还是欧洲市场，目前都缺少能够有效处理这种并发症的药物。Onconova公司CEO Ramesh Kumar今天表示公司将一如既往的致力于推动rigosertib的研发。不过，再获得FDA和欧洲医药管理部门点头同意之前，Onconova公司首先要解决的是从哪里找到一个新的合作伙伴来分担研发费用。
详细英文报道：
Baxter ($BAX) is scaling back its support of Onconova's ($ONTX) lead candidate, nixing plans to pay for European trials and paring down the potential of what could have been a $565 million deal for the biotech.
The drug, rigosertib, is designed to treat myelodysplastic syndrome, a rare bone marrow disorder that often develops after cancer treatment. Baxter bought into the program in 2012, paying $50 million up front and promising up to $515 million more in exchange for the European rights to the drug. However, after a series of clinical setbacks, Baxter is now calling off its plans for new studies and an eventual regulatory submission for rigosertib in low-risk MDS, news that sent Onconova's shares down about 35%.
While Baxter's decision makes Onconova ineligible for some undisclosed milestone payments, the move doesn't affect the pair's European collaboration on rigosertib in high-risk forms of MDS or in pancreatic cancer, the biotech said.
Meanwhile, in the U.S., Onconova is working to pick up the pieces of a clinical trial failure that has severely dampened rigosertib's prospects.
Last year, the drug failed to achieve a statistically significant improvement in overall survival compared to standard care in high-risk MDS, but Onconova is planning to launch another Phase III trial targeting the subgroup of patients that responded well to the intravenous treatment, angling to make rigosertib a second-line therapy for those who fail on hypomethylating agents.
"There have been no drug approvals in the U.S. since 2005 to address the unmet medical need of these patients," CEO Ramesh Kumar said in a statement. "We remain committed to developing rigosertib IV to meet the needs of this underserved patient population."
First, Onconova will need the blessing of the FDA and the European Medicines Agency to get another pivotal trial rolling, and the company would have to secure what it calls "appropriate financing" to pay for the effort.
Leerink analyst Howard Liang, for one, is less than optimistic about Onconova's odds, pointing out in an investor note that "while there appears to be a signal in certain subgroups of the previous Phase III study in (high-risk MDS) setting, we are generally not a big fan of relying on subgroup analyses, especially in a possible scenario that the outlook of the entire company could be dependent on such an analysis."