The Circuitous Route to Phase 3:  Another Chapter in the Fitful Development of PTK-0796

When antibiotics change hands, it can be a good thing.  Small companies are often desperate to attract a partner with ‘deep pockets’ to help them finance an expensive late phase development but often have to give up control once the honeymoon period is over.  Such transitions can bring delays because new teams need to come up to speed and new objectives require adjustment to the Clinical Development Plan (CDP).Detour-1

One would assume that the last thing the acquiring company wants is a loss of momentum.  In a small company, the few development assets get all the attention.  However, as one of many projects in a corporation even a newly acquired compound can easily become deprioritized for internal or external reasons.  As we all know, changes in the regulatory environment – like infeasible new FDA guidelines – have caused companies to move away from a particular ID projects or to abandon the entire Therapeutic Area of anti-infectives.

Paratek’s omadacycline (PTK-0796) is a case in point.  It must be the record holder for collaboration deals and, still, more than others it was tossed around by the whims of shifting corporate priorities.  For a drug with a very broad Gram-negative activity, including MDR pathogens, one would have expected development in the fast lane but the fate of PTK-0796 more resembles a rollercoaster ride:  First partnered with GSK, then with Bayer (now called BAY 73-6944/PTK 0796), followed by Merck for Phase 1 development (not sure whether Merck actually did any studies), the compound was finally inlicensed by Novartis in Phase 2½.  After a few years without recognizable progress the marriage was over before the drug even advanced into Phase 3.

Now we hear about the reverse merger with Transcept and that it would enable Paratek to finally start a pivotal Phase 3 program in ABSSSI.  Here the timeline:

2014      Paratek merges with Transcept
2009      Deal with Novartis – it fell apart for unclear reasons in 2011
2005      Deal with Merck – it fell apart over “difference in opinion about future direction of development”[1]
2003      Deal with Bayer – it fell apart when Bayer “turned its attention elsewhere”[2]
1999      Deal with Glaxo – it fell apart when GSK “pulled support for antibacterial R&D”[3]

Just to be clear:  Before the collaboration with Novartis, Paratek had started a Phase 3 program on its own which was stopped prematurely (when the company ran out of money?).  It seems Phase 3 was started on a wing and a prayer hoping to attract a suitor fancying a Phase 3 program.  This effort of ‘dressing up the bride’ did not work quite as expected: the study was stopped after enrolling only 143 of 790 patients planned.[4]  Now, 4-5 years later, Transcept will have to start Phase 3 again.

Currently, does not list any ongoing Phase 3 trials although the company seems to have received Special Protocol Assessment (SPA) for its new ABSSSI protocols and should be raring to go.

In summary, it took approx. 12 years to get this drug from IND to Phase 3.  It sure must be a big disappointment to see that late-starter eravacycline (from Tetraphase) now has caught up with omadacycline and is much closer to an NDA filing.

While VC companies can be counted on to run rings around ‘Big Pharma’ when it comes to development speed, PTK-0796 seems to be the exception that proves the rule.

There is a bit of good news of late:  FDA granted omadacycline QIDP status.  Let’s hope Transcept does not use up this patent extension trying to find a new partner.



Print Friendly, PDF & Email

Leave a Reply

Your email address will not be published. Required fields are marked *