AstraZeneca has made a push into the market for antibody-drug conjugates (ADCs) via the acquisition of Spirogen and a licensing deal with ADC Therapeutics.
The agreements will allow it to “accelerate ADCs into the clinic”, according to Dr Bahija Jallal, executive vice president of AZ’s MedImmune subsidiary.
ADCs combine the targeting power of antibodies with another active agent – typically a cytotoxic drug – that is designed to boost their activity but minimise side effects on other cells and tissues in the body.
The field is still in its infancy but is predicted to reach a value of $9bn by 2023 from its 2012 level of around $140m, according to data from Roots Analysis.
AZ is paying $200m to buy Spirogen outright – effectively bolting on the biotech company’s ADC generation platform into its own oncology R&D portfolio – with another $240m in the offing if certain preclinical candidates at Spirogen meet development targets.
Spirogen has developed a proprietary cytotoxic technology based on pyrrolobenzodiazepines (PBD) which can be joined to antibodies using biodegradeable linkers and kill cells using a mechanism of action distinct from currently used payloads such as auristatins.
Spirogen has also taken a non-ADC PBD compound called SG2000 into phase II trials in the US in solid tumours including ovarian carcinoma, and is planning similar studies in Europe.
In a related move, AZ is also paying $20m to take an equity stake in ADC Therapeutics, which had a licensing contract in place with Spirogen, and secure rights to two ADCs in preclinical development. Both Spirogen and ADC Therapeutics are owned by private equity firm Auven Therapeutics.
“The cutting-edge technologies developed by Spirogen and ADC Therapeutics complement MedImmune’s innovative antibody engineering capabilities,” commented Jallal.
After a false start in 2000 with the launch and subsequent withdrawal from the market of Mylotarg (gemtuzumab ozogamicin) from Wyeth (now Pfizer), the ADC field has started to gather pace, with dozens of candidates now in development.
2011 saw the launch of Seattle Genetics’ Adcetris (brentuximab vedotin) for Hodgkin’s lymphoma and systemic anaplastic large-cell lymphoma – which accounted for the entire ADC market last year. Meanwhile earlier in 2013 Roche debuted its breast cancer treatment Kadcyla (trastuzumab emtansine) which has been tipped as a possible $5bn blockbuster.