Sales of Boston Scientific Corp.’s Taxus coronary stent remain well off last year’s pace and have declined significantly over the past two years due to increased competition, according to regulatory filings (PDF) by the Vancouver-based pharmaceutical company that makes the drug used in the stent’s coating.

But there are signs that one of the Natick-based medical device giant’s core products might be on the rebound, according to Angiotech Pharmaceuticals Inc., which makes the paclitaxel that’s eluted by the stent’s coating. The drug is designed to reduce restenosis, or a re-narrowing of the blood vessel after the stent is implanted.

The company reported that second-quarter royalty revenues derived directly from Taxus sales were off 32 percent from the same period last year. But the royalties are derived from sales Boston Scientific reported during the first quarter, when sales of the Taxus line declined about 28 percent, according to regulatory filings .

Angiotech reaps about 6.5 percent of total net sales of Taxus stents worldwide. The company reported just under $17 million in royalty payments during the three months ended June 30, compared to about $26 million for the same period last year.

On a quarter-by-quarter basis, however, the company reported a slight rebound in royalty payments from BSC and company officials sounded optimistic that Taxus sales may have “stabilized after several quarterly periods of significant decline.”

In July, BoSci reported that second-quarter drug-eluting stent sales increased 15 percent but didn’t provide a breakdown along product lines.

The company also received favorable regulatory news in July, landing Food & Drug Administration clearance to market the Taxus Liberté long stent in the United States.