Pfizer has out-licensed an early-stage cancer monoclonal antibody to US biotech firm VLST Corp.

The privately-held Seattle-based company is getting hold of CP-870,893, an anti-CD40 monoclonal antibody that has been evaluated "in a number of preclinical and clinical trials" which have established its safety and maximum tolerated dose. VLST, which recently raised $5 million in a series B financing, plans to advance the compound "into efficacy studies in an oncology setting [and] is currently evaluating multiple clinical opportunities".

Under the terms of the agreement, Pfizer will retain co-exclusive rights to CP-870,893 in the oncology vaccine field. The drugs giant is also taking a 5% stake in VLST, the latter's chief executive Martin Simonetti told Xconomy, adding that the drug would appear to be most promising when used in combination with chemotherapy.

Garry Nicholson, head of Pfizer Oncology, said the agreement is yet another example of how the company is "executing against its portfolio management goals in oncology while finding a positive way forward for those compounds leaving our pipeline". He added that "VLST’s expertise in immunotherapy makes the company a strong partner to continue the development of this compound".

FDA warns about Revatio in under-17s

Meantime, the US Food and Drug Administration has issued a safety communication warning against the off-label use of Pfizer's pulmonary arterial hypertension drug Revatio (sildenafil) in children aged under 17.

The agency says its recommendation against use is based on a recent long-term clinical paediatric trial showing thatchildren taking a high dose of Revatio had a higher risk of death than those on a low dose. Furthermore, the FDA says low doses of Revatio are not effective in improving exercise ability.

The label on Revatio, which has the same active ingredient as Pfizer's erectile dysfunction blockbuster Viagra, will carry the warning.