* Third trial to show desired results in lung cancer

* Anti-inflammatory drug showed oncology potential in 2017

* Analysts still see growth potential in inflammation setting

ZURICH, Aug 15 (Reuters) - Efforts by Novartis to show that an established anti-inflammatory drug could also suppress cancer growth were dealt a final blow when a third big lung cancer trial failed to produce the desired results.

The Swiss drugmaker said on Monday its canakinumab drug did not slow the progression of non-small cell lung cancer in a late-stage trial, when given to prevent relapse in patients that were diagnosed early enough for tumour-removal surgery.

The failure in the latest trial, called Canopy A, is a setback for Novartis after canakinumab failed in two separate studies last year where the drug was tried in combination with other treatments on lung cancer patients at a more advanced disease stage. "Consensus expectations for this high-risk project remained zero or low with the remaining market exclusivity for canakinumab limited until 2028," said Zuercher Kantonalbank analyst Laurent Flamme.

He estimated annual sales of around 300 million Swiss francs ($317.9 million) by 2026 for the drug as an adjuvant treatment for non-small cell lung cancer.

The drug is approved to treat a number of inflammatory disorders under the brand name Ilaris with $284 million in revenues last year. Credit Suisse analysts said annual sales could reach more than $1 billion in that indication.

A cardiovascular disease trial in 2017 produced early indication that the drug might also play a role in preventing lung cancer by suppressing a type of inflammation that drives cancer growth. That prompted Novartis to launch a lung cancer trial programme.

Novartis needs to boost its pharma development efforts as it is conducting a strategic review of its off-patent generic drug business Sandoz that might result in a sale.

It has billions at its disposal for deals to strengthen its research pipeline after selling its 33% stake in Roche back to the Swiss rival last year for $20.7 billion.

($1 = 0.9436 Swiss francs) (Reporting by John Revill in Zurich, Ludwig Burger in Frankfurt; Editing by Emelia Sithole-Matarise and Bernadette Baum)