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IPOs ‘sore’ in 2013; Genocea joins in with herpes drug bid

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By Randy Osborne
Staff Writer

With vaccines in the works for herpes simplex virus 2 (HSV-2) and pneumonia, Genocea Biosciences Inc. added to a banner year for initial public offerings (IPOs) in biotech, filing to go public and raise $75 million by way of selling an unspecified number of shares at an also-undisclosed price range.

At the start of December, Genocea started a Phase I study with GEN-004 for pneumococcus (Streptococcus pneumoniae), the first vaccine designed to block infections caused by all pneumococcus strains.

Recent scientific findings suggest Th17 responses make up a natural mechanism to clear pneumococcus from the nasopharynx, and GEN-004 contains three unique protein antigens – SP0148, SP1912 and SP2108 – that Genocea has proved to be associated with Th17 activity.

If the approach succeeds, it would represent an improvement over Prevnar 13, the shot from Pfizer Inc. that protects against 13 of the most common pneumococcal bacteria strains. Genocea’s backers include Polaris Venture Partners and Lux Ventures, among others.

The Cambridge, Mass.-based firm’s most recent financing was the Series C round last fall, which brought aboard the Bill & Melinda Gates Foundation as a supporter. (See BioWorld Today, Oct. 11, 2012.)

Excitement also is gathering around Genocea’s protein subunit vaccine for HSV-2. Phase I/IIa data offered in September at the Interscience Conference on Antimicrobial Agents and Chemotherapy showed that patients given three doses of the vaccine, known as GEN-003, had reductions in the frequency of viral shedding of up to 51 percent (p < 0.001). The trial enrolled about 150 volunteers with moderate to severe HSV-2 infection who are otherwise healthy.

Those who received a placebo had no decline in viral shedding at all. T-cell immune responses increased more than 20-fold to one of the vaccine’s antigens (ICP4) and more than 10-fold to the other (gD2). Well-tolerated GEN-003 increased neutralizing antibodies to the HSV-2 virus fivefold, on average, compared to baseline values.

Results from an exploratory analysis also found that the interval between the first immunization and the next recurrence of herpes may be prolonged in patients who got the drug compared to those who received placebo, though the trial was not designed to test whether GEN-003 improves symptoms or reduces the frequency of recurrent disease.

The quest for a herpes vaccine has been long. In 2010, London-based Glaxosmithkline plc (GSK), having raised hopes for its candidate, Simplirix, quit development after the product bombed in Phase III trials. Details of the experiment, involving 8,323 women between the ages of 18 and 30, were published last year in the New England Journal of Medicine. The vaccine proved its mettle in HSV-1 but not against HSV-2, surprising since it did the job in two earlier studies. One of the top investors in Genocea is SR One, GSK’s venture arm.

GSK’s vaccine contained glycoprotein D (gD-2) plus an adjuvant. GD-2 is the entry receptor for HSV-2, and at the time of the pharma giant’s Phase III blowup, efforts to prevent genital herpes using gD-2 subunit vaccines had been ongoing for two decades at a cost of more than $100 million, according to a paper published in PLOS One. GD-2 is one of the proteins in Genocea’s vaccine; the other is infected cell protein 4.

AGENUX MAKING STRIDES

In the HSV-2 race with Genocea is Agenus Inc., of Lexington, Mass., which in November reported statistically significant top-line results from its Phase II randomized, double-blind, multicenter study with Herpv, a recombinant “off-the-shelf” therapeutic vaccine for HSV-2. Herpv contains a defined mixture of peptides representing HSV-2 antigens, plus Agenus’ QS-21 Stimulon adjuvant. Agenus’ vaccine includes 32 HSV-2-associated peptides.

Genital viral shedding was measured 45 days before and after three injections of Herpv. The primary analysis, which looked at viral shedding after the first three shots, showed that subjects who received Herpv had a statistically significant reduction in viral shedding (p = 0.015; RR = 0.85), suggesting a 15 percent reduction in viral shedding after the first treatment period and before the booster injection. The drug also gained a reduction in viral load of 34 percent, whereas placebo patients showed no reduction compared to baseline in either parameter.

Post-booster viral shedding results, along with immune response data, are expected from Agenus in the first half of next year.

The Centers for Disease Control and Prevention estimated that 776,000 people in the U.S. contract new herpes infections every year. Nationwide, 16 percent, or about one out of six, people 14 to 49 years have genital HSV-2 infection. It’s more common in women – about one of every five women 14 to 49, vs. one of every nine men in the same demographic – because transmission from an infected male to his female partner is more likely than the other way around.

BANNER YEAR FOR IPOS

IPOs were plentiful in 2013, collectively raising $2.9 billion as of the last week of December, according to BioWorld Snapshots. A recent report from Ernst & Young noted that the total number of IPOs across all industries this year was 222, compared to 133 last year, and 22 percent of 2013’s deals came from biotech. (See BioWorld Insight, Dec. 2, 2013.)

For Genocea’s IPO, Citigroup and Cowen and Co. are acting as joint book-running managers. Stifel, Nicolaus & Co. Inc. is serving as lead manager, with Needham & Co. LLC as co-manager. The company intends to trade on Nasdaq under the symbol “GNCA.”

In other financings news:

Ampliphi Biosciences Corp., of Richmond, Va., said it completed its sale of about $18 million of common stock in a private placement financing. The company issued an aggregate of 72 million shares priced at 25 cents each. Net proceeds totaled about $16.9 million and will be used to accelerate development of the firm’s bacteriophage-containing human therapeutics for use in treating bacterial infections. Roth Capital Partners and Griffin Securities Inc. served as placement agents. (See BioWorld Today, Dec. 17, 2013.)