AbbVie's Immunogen buy delivers rare cancer drug approval

The FDA has approved AbbVie's Decnupaz, a treatment for rare blood cancer blastic plasmacytoid dendritic cell neoplasm (BPDCN) that was one of the assets in its $10.1 billion takeover of ImmunoGen in 2023.

Decnupaz (pivekimab sunirine), a CD123-targeting antibody-drug conjugate (ADC), has been cleared for adults with BPDCN on the strength of the phase 1/2 CADENZA trial, which showed a near-70% complete response rate in newly-diagnosed patients, with a median duration of response of nearly 10 months.

The ADC was also able to achieve a complete response in around 16% of previously-treated BPDCN patients, with a median duration of just over none months, and some patients were able to go on to receive a potentially curative haematopoietic stem cell transplant (HSCT).

The results – showcased at last year's ASCO congress – are impressive in an aggressive blood cancer in which treatment for many years relied on intensive chemotherapy regimens borrowed from other blood cancers that have debilitating side effects and are associated with a high risk of relapse.

Affecting the blood and bone marrow, BPDCN can spread rapidly to other tissues and is characterised by bruised-looking skin lesions and tumours in the lymph nodes, spleen, and central nervous system. It typically affects older people aged 60 or more, with 500 to 12,000 new cases in the US each year, and has a median survival of just one to two years.

Decnupaz isn't the first CD123-targeting drug to be approved for the disease, as Menarini subsidiary Stemline Therapeutics' Elzonris (tagraxofusp) has been available since 2018 in the US to treat adults and children aged two and over with the cancer.

AbbVie said Decnupaz is "the first and only…ADC approved for [BPDCN] that is initiated in the outpatient setting." Decnupaz is administered as a 30- or 15-minute infusion every one to three weeks, while Elzonris requires a strict premedication regimen to reduce side effects and five daily infusions, within a 21-day cycle. It is recommended that the first cycle be administered on an inpatient basis.

Both drugs also carry black box safety warnings – hepatotoxicity and infusion reactions for AbbVie's drug and capillary leak syndrome for Elzonris.

BPDCN isn't expected to be a big commercial opportunity for AbbVie – annual sales of Elzonris were around $40 million before Stemline was taken over by privately-held Menarini in 2020 – but AbbVie is hoping to extend the use of the drug into the larger acute myeloid leukaemia (AML) category.

A mid-stage trial (REVIVAL) of Decnupaz in combination with Roche-partnered BCL-2 inhibitor Venclexta (venetoclax) and azacitidine, in newly diagnosed, untreated patients with AML who are ineligible for intensive chemotherapy, is scheduled to start later this year.