Celgene's much-fancied new bone marrow cancer therapy Pomalyst has been approved in the US, giving the firm another likely blockbuster to help it compete with its rivals in the category.

Pomalyst (pomalidomide) has been given the nod to treat patients with multiple myeloma whose disease progressed after being treated with other cancer drugs, including Celgene's own Revlimid (lenalidomide) and Takeda and Millennium's Velcade (bortezomib) which claims it has a 50-60% share of the myeloma market.

The approval comes on the back of strong Phase III data - reported at last year's American Society of Hematology (ASH) meeting - which showed that 29 per cent of relapsed or refractory multiple myeloma patients treated with Pomalyst plus dexamethasone saw their cancer completely or partly disappear, with the response lasting for more than seven months.

Last month, Celgene's chief executive Bob Hugin told analysts on the company's results conference call that the high unmet medical need in patients with relapsed/refractory multiple myeloma and the strong data mean that that Pomalyst "is positioned to become our next blockbuster in haematology."

Revlimid is already a major earner for the company with sales clearing the $1 billion threshold for the first time in the fourth quarter of 2012, and analysts have suggested Pomalyst could add another $1-$2 billion to Celgene's myeloma franchise.

"Together with Revlimid, this novel therapy may help make it possible for haematologists and their patients to think of a future when this incurable cancer becomes a chronic disease," said Hugin.

Outside the US, Pomalyst has also been submitted for approval in Europe for multiple myeloma, with a verdict expected in the latter half of 2013, while a bridging study is ongoing to allow Celgene to file for that indication in Japan.

Meanwhile Celgene sees additional potential for Pomalyst in myelofibrosis, another disorder of the bone marrow, and expects to report Phase III data in this indication in the first half of 2013. Among the efficacy measures in the study will be Pomalyst's ability to resolve transfusion-dependent anaemia in myelofibrosis patients.

With Revlimid on fine form, Pomalyst rolling out and Vidaza (azacitidine) for myelodysplastic syndromes and pancreatic cancer therapy Abraxane (nab-paclitaxel) still in the growth phase, Celgene should have "three haematology and oncology brands generating $1 billion or more in annual sales within the next three to five years," said Hugin.