A stunning $792.6 million underwritten public offering from Biomarin Pharmaceutical Inc. generated considerable buzz on social media Thursday morning after the company disclosed the pricing of 8.5 million shares – upsized from 7.25 million in its preliminary prospectus – at $93.25 apiece.

Biomarin, of San Rafael, Calif., granted underwriters a 30-day option to purchase up to an additional 1.275 million shares, potentially adding another $118.9 million to its haul, which the company said will be used, in part, to fund its recent acquisition of Prosensa Holding NV, of Leiden, the Netherlands.

That deal, disclosed in November, was worth about $680 million up front, or approximately $17.75 per share, with another $160 million tied to FDA and European approvals of Duchenne muscular dystrophy (DMD) drug drisapersen by May 15, 2016, and May 15, 2017, respectively. (See BioWorld Today, Nov. 25, 2014.)

As predicted last week by Biomarin CEO Jean-Jacques Bienaimé at the company's presentation on the opening day of the 33rd J.P. Morgan (JPM) Healthcare Conference in San Francisco, Biomarin reported several days later that approximately 93.4 percent of Prosensa's outstanding shares were tendered during initial offering period.

At JPM, Bienaimé offered details of the interim results, reported earlier that day, from its phase I/II pivotal study of BMN 190, or cerliponase alfa, a recombinant human tripeptidyl peptidase 1 (rhTPP1) in development to treat of patients with late infantile CLN2 disease, a form of Batten disease. He showed individual slides for each of the first nine patients treated with BMN 190, offering compelling evidence of disease stabilization on the drug – "substantially better than expected" by the company, he noted – and maintained that Biomarin expects to file for registration of the drug in the indication following completion of the study later this year.

Bienaimé moved on to review the remainder of Biomarin's pipeline, beginning with drisapersen, and explained the strategic rationale for the Prosensa acquisition, which he said was based on "very, very solid due diligence," including Biomarin's belief that, given the unmet medical need, drisapersen will likely gain early approval in the U.S. and Europe.

Drisapersen has the largest dataset in DMD, he added, including three placebo-controlled studies and two long-term open-label studies that, combined, treated more than 300 patients, with a discontinuation rate of less than 1 percent in the regular studies and less than 3 percent in the extension studies. Drisapersen was the only DMD drug to be developed under the FDA's breakthrough therapy designation and is currently under rolling review, with a complete new drug application submission to the FDA expected in the first quarter.

Bienaimé described the acquisition of Prosensa as "a perfect strategic fit" for Biomarin, based on the company's mission to develop drugs for rare and ultra-rare diseases and its global regulatory and commercial infrastructure. Drisapersen, he added, "could be our largest product in the short- to medium-term," based on the potential to address 13 percent of the DMD population, or an estimated 10,000 patients. He cited as a benchmark the pricing in Germany of €400,000 (US$452,800) per patient per year for the "complementary" therapy Translarna (ataluren, PTC Therapeutics Inc.), conditionally approved last August in nonsense mutation DMD. (See BioWorld Today, Oct. 13, 2014.)

"You can do the math on the market size here," he said.

'A CATALYST-RICH YEAR THAT DRIVES UPSIDE'

That's when Bienaimé strayed into controversial territory. He used a slide comparing long-term study data from patients on drisapersen to natural history, including patients who lost ambulation, to segue immediately to a slide comparing drisapersen head-to-head with eteplirsen, based on data extracted from an investor presentation by that compound's developer, Sarepta Therapeutics Inc., of Cambridge, Mass.

Bienaimé spent barely a minute on two slides, almost in a throwaway manner, suggesting that drisapersen "compared favorably to competition," despite the fact that the two candidates have never been studied side by side. The same day, Cambridge, Mass.-based Sarepta reported data through week 168 from Study 202, its open-label phase IIb extension study of eteplirsen in patients with DMD, showing that evaluable patients had continued ambulation on the six-minute walk test but at a decline in distance since measured at 144 weeks.

The Sarepta news was not completely unexpected, according to analysts, but the Biomarin comparison of the two unapproved drugs lit up Twitter, not to mention JPM cocktail chatter. Perhaps not coincidentally, Sarepta's shares (NASDAQ:SRPT) fell that day to a one-year low of $11.33 before closing at $11.91.

In his presentation on the closing day of JPM, Sarepta president and CEO Chris Garabedian denounced the "cross-study" comparisons, noting he was approached by researchers "who were confused" about the conclusions. He insisted the eteplirsen Study 201 patients were not recruited into an open-label single-arm study, as suggested by Bienaimé, and said the study met its primary endpoint in the intent-to-treat population. Garabedian also maintained that Sarepta is "committed to transparency in all of our studies," including the provision of all biopsy results and regular, ongoing clinical results, and he questioned the lack of safety data on drisapersen in the Biomarin presentation.

Shouting wars aside, Biomarin clearly gained momentum at JPM, with the J.P. Morgan research team citing the company, along with Clovis Oncology Inc., for "the most encouraging fundamental developments" at the conference. In a note, Cory Kasimov and colleagues observed that "BMRN's unexpected update of BMN 190 data in Batten disease during its presentation was highly impressive, in our view," noting that clear activity in the first nine of 24 enrolled patients suggested "BMN 190 has a very high probability of approval. This drug also fits right in BMRN's wheelhouse; it's for an underdiagnosed ultra-orphan condition that will command premium pricing and likely turn low incidence [400-600 patients per year] into a higher level of prevalence." They predicted the product could generate several hundred million dollars in annual revenues.

Wells Fargo Securities LLC analyst Brian Abrahams agreed, calling Biomarin's JPM presentation a "solid start to 2015," which he called "a catalyst-rich year that drives upside for the company."

Biomarin's Street cred also is evident in its rising stock price, which topped $100 in four of the last six sessions and hit a one-year high of $100.50 on Jan. 15. Following JPM, Jefferies LLC analyst Eun Yang raised the company's price target to $114, from $100, citing management's expectation of profitability next year at approximately $1 billion in revenues and the company's focus on new product generation and pipeline growth.

The company's offering priced at a discount of 3 percent to Wednesday's closing price of $96.14. Shares (NASDAQ:BMRN) closed Thursday at $93.79, off $2.35.

The offering is expected to close by Jan. 27. BofA Merrill Lynch, J.P. Morgan Securities LLC and Morgan Stanley & Co. LLC are acting as joint bookrunners, with Barclays Capital Inc. and Deutsche Bank Securities Inc. as co-managers.

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