Daiichi boosts cancer pipeline with $410m Ambit acquisition

Japan’s Daiichi Sankyo has agreed a deal to buy Ambit Biosciences of the US for up to $410 million, bringing a new leukaemia candidate into its pipeline.

The $15-per-share cash deal – which could rise to $19.50 per share if additional clinical and regulatory milestones are achieved – is firmly focused on quizartinib, Ambit’s lead drug which is in phase III trials for acute myeloid leukaemia (AML).

Ambit said recently it expects to have 110 clinical sites recruiting AML patients into its trial by the end of the year, with enrolment expected to be completed in the second half of 2015.

Quizartinib is a FLT3 inhibitor, so is specifically intended to treat AML patients who have the FLT3 genetic mutation and – as a result – have a poorer prognosis than those whose cancers are FLT3-negative.

In phase II trials involving around 400 patients reported earlier this year involving refractory or relapsed AML, around 47 per cent of patients experienced a composite complete response (CRc) – defined as the sum of complete remission (CR), CR with incomplete platelet recovery (CRp) and complete remission with incomplete haematologic recovery (CRi).

Use of the drug as a bridging therapy was also shown to help relapsed AML patients reach remission and become eligible for a stem cell transplant to try to cure the disease.

The company has also been developing quizartinib for additional indications, including newly-diagnosed AML patients and as a maintenance therapy in those undergoing a stem cell transplant, as well as combination studies with other drugs including Celgene’s Vidaza (azacitidine) or low dose cytarabine.

For Daiichi Sankyo, the acquisition of Ambit is its third bolt-on deal in oncology, having bought U3 Pharma in 2008 and Plexxikon in 2011. Cancer is a core R&D area for the Japanese group and quizartinib will slot in alongside other phase III projects including tivantinib for liver cancer, breast cancer therapy denosumab and nimotuzumab for stomach cancer.

“The acquisition of Ambit Biosciences further builds our presence in oncology to ensure we are delivering on our goal of providing world class, innovative pharmaceuticals in core areas of unmet medical need,” commented Daiichi Sankyo chief executive Joji Nakayama.

The Japanese firm reached a deal earlier this year to sell its Indian generics subsidiary Ranbaxy – currently wrestling with manufacturing problems, to Sun Pharma for $4 billion.

Other companies that have developed FLT3 inhibitors for AML include Cephalon (now part of Teva) – which reported disappointing data with its lestaurtinib candidate a couple of years ago, and Novartis’ midostaurin (PKC142), which is in phase III and could be filed in 2015.

Meanwhile, kinase inhibitors with FLT3 activity – including Pfizer’s Sutent (sunitinib), Bayer/Onyx’ Nexavar (sorafenib), and Ariad Pharma’s Iclusig (ponatinib) – have shown some activity in AML trials and have been used off-label in AML patients.

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