* Novartis offers $3.9 bln for AAA
* Cash deal reflects 47 pct premium
* French company had H1 sales of $78 mln (Adds offer premium, quotes from Novartis and AAA, details)
ZURICH, Oct 30 (Reuters) - Swiss drugmaker Novartis on Monday offered to buy France's Advanced Accelerator Applications (AAA) in a $3.9 billion cash deal to strengthen the oncology portfolio at the world's biggest maker of prescription medicines.
Basel-based Novartis's offer of $41 per ordinary share and $82 per American depositary share represents a 47 percent premium to AAA's price before media reports on Sept. 27 that Novartis was interested.
It said it would finance the deal with debt.
Novartis is seeking to add AAA's radiopharmaceuticals that use trace amounts of radioactive compounds to not only create functional images of organs and lesions but also to treat diseases like cancer.
AAA's flagship product, Lutathera, won European Union backing in late September for use against gastroenteropancreatic neuroendocrine tumours, the kind of cancer that killed Apple founder Steve Jobs.
"Novartis has a strong legacy in the development and commercialisation of medicines for neuroendocrine tumors where significant unmet need remains for patients," Bruno Strigini, head of Novartis Oncology, said in a statement.
"With Lutathera we can build on this legacy by expanding the global reach of this novel, differentiated treatment approach."
Lutathera, which has also been submitted to the U.S. Food and Drug Administration for approval, harnesses a molecule not only to diagnose cancer but also to deliver treatment by hitting cancer cells with high-energy electrons.
In a separate statement, AAA Chief Executive Stefano Buono said his company backed the deal, not only to support Lutathera's expanding launch but also to speed up development of its other therapies.
"We believe that the combination of our expertise... together with the global oncology experience and infrastructure of Novartis provide the best prospects for our patients, physicians and employees, as well as the broader nuclear medicine community," Buono said.
AAA, which was spun off from Europe's physics research centre CERN 15 years ago and listed on Nasdaq, had sales of $78 million in the first half of 2017, with a net loss from continuing operations of $24.2 million. (Editing by Michael Shields)