Paratek hopes antibiotic success is infectious

Sixteen years, at least six venture rounds and a reverse merger to access public markets has pushed Paratek Pharmaceuticals to the brink of success. The positive phase III data in skin and skin structure infections it has reported for its lead project, omadacycline, should spark interest in dealmaking with the Massachusetts-based group.

Proving that its tetracycline-based antibiotic is the equal of Pfizer’s Zyvox using both US and European endpoints has raised hopes that it will also be successful in a pneumonia trial that will be necessary for regulatory approval. Shares rose 7% to $17.61 in early trading today.

More treatment options

Omadacycline and Zyvox were tested for up to 14 days in an intravenous-to-oral trial in 645 patients hospitalised for wound infections, cellulitis and erysipelas or major abscesses. Three endpoints were necessary – one, early clinical response, to satisfy the US FDA, and two measures of investigator-assessed clinical response post-treatment, to satisfy the European Medicines Agency.

Using the FDA’s requirements, a similar percentage of patients taking omadacycline and Zyvox, 84.8% versus 85.5%, demonstrated a 20% reduction in lesions 48 to 72 hours after treatment began.

For the EMA’s endpoint, a similar number of patients saw resolution of signs and symptoms seven to 14 days after the end of treatment, measured either as a modified intention-to-treat or a clinically evaluable population. The percentage achieving those endpoints for omadacycline and Zyvox respectively was 86.1% versus 83.6% on intention to treat, and 96.3% versus 93.5% among clinically evaluable patients.

Achieving non-inferiority is often a threshold for success in anti-infective treatments because of resistance to existing agents. Physicians and regulators have been seeking new alternatives for some time, which is why the US government created the Qualified Infectious Disease Product programme in the last re-authorisation of PDUFA.

This programme grants priority review and an extra five years of market exclusivity for approved drugs to treat such difficult bacteria as meticillin-resistant Staphylococcus aureus; omadacycline has won QIDP status.

The partnering game

Success in this setting should raise the odds that a partner or buyer for Paratek will emerge. EvaluatePharma’s consensus of sellside analysts forecasts $308m in 2022 sales, although a share of this is likely to be ascribed to the community-acquired bacterial pneumonia indication that has yet to report phase III data.

A phase III pneumonia trial is under way and expected to read out in the latter half of 2017 before regulatory applications are submitted in 2018. The structure is similar – an early response endpoint and a longer-term evaluation post-treatment in 750 patients randomised to take omadocycline or moxifloxacin.

The group has said it intends to partner outside the US and European markets and will reserve at least some commercialisation rights in those key markets. As the IV version of omadacycline will be used exclusively in hospitals, a smaller biotech like Paratek could conceivably muster a sales force for this small set of customers.

This dataset should spark some talks with bigger players – Merck & Co and Allergan are two companies active in this space, and Allergan already knows Paratek through its partnership on a second anti-bacterial, sarecycline. A third group with an interest in skin infections, the Medicines Company, looks less likely as a bidder since it has moved aggressively into cardiovascular care.

In the absence of dealmaking, today’s share rise could be a spark for another share offering. The group’s executives say they have enough cash to fund operations through the pneumonia readout next year, although if R&D spending continues at the $24m rate seen in the first quarter of 2016 alone the $112m cash and securities will dwindle rather fast. And building commercial capacity, should that be still part of the company’s strategy, will only add to spending.

Regardless of progress with bigger players, executives may want to take advantage of today’s share rise. In the current market valuations boosts like this are often short-lived, and it could be a year before Paratek sees another catalyst like this one.

To contact the writer of this story email Jonathan Gardner in London at jonathang@epvantage.com or follow @ByJonGardneron Twitter

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