Speaking during a question-and-answer session at the BIO CEO & Investor Conference in New York on Tuesday, chief executive N. Anthony Coles said that South San Francisco, Calif.-based Onyx could look to either licensing opportunities or early-stage deals with a purchase option to augment its current drug pipeline.

"I think we have to continue to be opportunistic," he said. "Across the span of development, if there are attractive oncology assets, we'd be very interested in considering those to [boost] the pipeline."

Onyx doesn't have a long track record of acquisitions, but the only deal it has made appears to be on the verge of paying off in spades. The company paid $276 million for Proteolix Inc. in 2009, a deal that included a compound now known as Kyprolis that won Food and Drug Administration approval in July and is now expected by analysts to eventually bring in more than $1 billion annually.

Onyx has the capital to do a deal, having raised $358 million by selling 4.4 million shares of stock in mid-January, though it said at the time it would use the cash for research and development and marketing purposes. Onyx had about $230 million in cash and cash equivalents as of Sept. 30, the date it filed its last quarterly report with the Securities and Exchange Commission.

Coles joked Monday that the company has grown from a "half-a-product" company to one with three therapies. Onyx was first known for Nexavar, a kidney and liver cancer drug that it co-markets with Germany's Bayer AG. The two split profits on the drug, which brought in $1 billion in 2011.

They are also partners on drug for colorectal cancer known as Stivarga. Bayer developed the drug, but Onyx will receive 20% royalties on all global net sales. The FDA approved Stivarga in the U.S. in September.

Onyx is also teamed with Pfizer Inc. on a breast cancer drug known as PD-991 that posted impressive Phase 2 data in December and is expected to head into Phase 3 trials this year.

But Onyx's biggest victory to date was when it won FDA approval of Kyprolis in 2012. The drug has already posted $62 million in sales since its launch. Onyx hopes to both roll it out globally and expand its potential market through other late-stage trials.

Coles said Tuesday that the multiple myeloma market is worth $5 billion globally and could almost double and hit $9 billion by 2017.

"We have been successful on the basis of two things: being willing to use a mix of collaborations, and our own proprietary therapies to build our business," Coles said.

Onyx's growing product offerings have made it a more attractive takeover candidate. A flurry of buyout rumors surrounded Onyx in late 2011 after unconfirmed reports surfaced claiming the drugmaker had hired an investment adviser. Development partners Bayer and Pfizer were linked to Onyx, though no deal ever surfaced.

In the meantime, Onyx's value has skyrocketed. The stock, which was worth about $30 per share in fall 2011, has more than doubled in value; it traded at $73.68 per share early Tuesday, giving it a market capitalization of close to $5 billion.