Cell Therapeutics received a major boost, and validation, when it announced that a second independent radiologic review of data from the pivotal trial PIX301 confirmed the statistical significance of response and progression endpoints of the study. PIX301 was the basis of the original new drug application (NDA) filed by Cell Therapeutics for approval of its lead pipeline candidate pixantrone. Pixantrone has been developed for the treatment of relapsed or refractory aggressive non-Hodgkin’s lymphoma (NHL) in patients who have not responded to other treatment options.
The independent radiologic review was conducted by an independent panel of three radiologists to determine the soundness of the primary endpoint of the PIX301 study. The radiologic review was recommended by the Office of New Drugs (OND) of the FDA in May 2011.
The FDA had issued a complete response letter (CRL) in April 2010 to the NDA for pixantrone based on concerns that PIX301 has not proved sufficiently the effectiveness of the drug. The FDA asked Cell Therapeutics to conduct an additional trial to determine the safety and efficacy of pixantrone. Even though the company began an additional trial (PIX306) for pixantrone, the company appealed to the Office of New Drugs (OND) in December 2010 to reverse the FDA’s decision to deny approval to pixantrone. In early May 2011, Cell Therapeutics met with the Office of New Drugs (OND) of the FDA which allowed the company to re-submit the NDA for review without the need for an additional trial. In addition to the independent radiologic review, the OND recommended that Cell Therapeutics will also require submitting new information regarding circumstances of stopping the PIX 301 trial early.
The company is looking for accelerated approval of the NDA based on data from the PIX301 study. Cell Therapeutics is hoping to re-submit the NDA on the basis of results of the radiologic review in October 2011. The Division of Oncology Drug Products (the DODP) will review the NDA within six months of the resubmission setting forth a target date in April 2012.
The opportunity to re-submit the NDA revived the prospects of pixantrone and removed a major overhang for the company. The company has saved 2-3 years by getting the opportunity to file on the basis of the original completed trial PIX301 instead of the new trial PIX306. The supportive results from the second independent radiologic review further strengthen the prospects of the drug.
We currently have a Neutral recommendation on Cell Therapeutics.
We believe the uncertainty surrounding the approval of pixantrone in the US has eased following the opportunity given by the FDA to resubmit the NDA. Moreover, the drug is under review in Europe and is expected to be approved in early 2012. That apart, Cell Therapeutics’ other pipeline drugs Opaxio and tosedostat, also studied for different types of cancers, create synergies with pixantrone. However, we prefer to remain on the sidelines given that Cell Therapeutics is overly dependent on the approval of pixantrone. Therefore, any delay in gaining approval would be a major blow for the company.