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AiCuris' Phase II CMV Drug Lures Merck: $142M Up Front

By Randy Osborne
Staff Writer

Merck & Co. Inc.'s tie of the licensing knot with AiCuris GmbH & Co. brought €110 million (US$142.2 million) up front and could mean another €332.5 million in milestone payments for AiCuris, with a cytomegalovirus (CMV) candidate impressive in Phase II trials.

Wuppertal, Germany-based AiCuris, a spinout from Bayer AG, earlier this year disclosed Phase II data showing that the oral quinazoline letermovir worked and proved tolerable in a trial with 133 bone marrow transplant patients with CMV.

Given for 84 days at two doses – 120 mg and 240 mg once daily – letermovir met both primary efficacy endpoints with high statistical significance vs. placebo: incidence and time to onset of CMV prophylaxis failure. Based on the Phase II data, AiCuris said in February that it was preparing for Phase III development.

Enter Merck, of Whitehouse Station, N.J., which gets worldwide rights to develop and sell all of AiCuris' CMV portfolio. The potential milestones are based on success with letermovir, plus a backup candidate and other Phase I compounds with a different mechanism of action. AiCuris would get royalties, too, of an undisclosed amount "reflecting the advanced stage of the clinical program."

Ian McConnell, spokesman for Merck, said the AiCuris candidate "dovetails into our anti-infectives portfolio" and brings aboard a CMV program, which Merck lacked, and a late-stage one at that.

"There's nothing out there on the prophylaxis side," McConnell noted.

CMV, a common member of the herpes family of DNA viruses, usually stays dormant in humans. A small handful of drugs is approved for attacking CMV, but most hamper the immune system and target the viral DNA polymerase, bringing with them a potential cross-resistance issue. The current lineup includes ganciclovir, valganciclovir (an orally available prodrug of the same molecule), valacyclovir (an oral version of acyclovir), cidofovir and foscarnet.

Letermovir, on the other hand – fast-tracked by the FDA – takes aim at the UL56 subunit of the viral terminase complex.

AiCuris, which gained ownership of AIC246 when it was spun out of Bayer HealthCare (a subsidiary of Leverkusen, Germany-based Bayer AG) in 2006, aims to develop the drug as a safer prophylactic therapy.

CMV, which can be especially problematic for transplant recipients, babies and HIV patients, has been a favored, if challenging, target for drug developers taking either the prophylaxis approach or, in the case of transplants, pre-emptive treatment of at-risk patients and those who show up with CMV when screened.

As far back as April 2010, AirCuris' efforts in anti-infectives were being appreciated. That's when the firm raised €50 million (then US$75 million) from Andreas and Thomas Strüngmann, of Santo Holding, the twin brothers who once owned the generics firm Hexal, now part of Basel, Switzerland-based Novartis AG. (See BioWorld Today, April 15, 2010.)

In September, Abbott, of Abbott Park, Ill., signed a deal with Tokyo-based Astellas Pharma Inc. to collaborate on a Phase III trial testing ASP0113 (TransVax), an investigational vaccine licensed from Vical Inc., of San Diego, for preventing CMV reactivations in transplant patients.

Trellis Bioscience LLC, of South San Francisco, in August won a four-year, $3.3 million Small Business Innovation Research fast-track grant for its preclinical native human antibody against CMV.

And the month before that, London-based Cell Medica Ltd. raised £17 million (then US$26.5 million) for work that includes Cytovir CMV, composed of T cells purified from donated bone marrow tissue, which are transfused into the recipient to get CMV immunity back after a transplant. Cytovir CMV is in two Phase III trials in the UK that are due to report mid-to-late next year. (See BioWorld Today, July 24, 2012.)

Another to wade into CMV waters lately is Theraclone Sciences Inc., of Seattle, which in June dosed the first subjects in a Phase I trial of TCN-202, a fully human monoclonal antibody in development for CMV. Results from the dose-escalation study, expected to enroll up to 80 healthy adults, are expected in the first half of next year.