My apologies, but it would seem I was wrong regarding my...

My apologies, but it would seem I was wrong regarding my assumption that the TPM injectable antibiotic being developed by Agila/Mylan was either Avelox (moxifloxacin) or Zyvox (linezolid). (1) That assumption was based, in part, on a statement made by POH that the patent of the relevant antibiotic would expire in 2014 (May 2013 Newsletter).

However it would appear that the antibiotic is in fact Cubicin (daptomycin), star product of antibiotic specialist Cubist, which was acquired by Merck last December for $9.5 billion.

Daptomycin is indicated for Complicated Skin and Skin Structure Infections, which corresponds with what we know about the antibiotic’s purpose. Global sales were in excess of $1 billion last year (with >90% of those sales in the US), further corresponding with what POH has said. However Cubicin’s key patents had been set to expire in 2020 – two were due to expire in 2020, two more were set to expire in 2019 and another in 2016. That changed last December when a US court struck down all but the 2016 patent. (2) As Hospira was granted a first-time generic approval by the FDA in September last year, it may be able to launch its Cubicin generic  from mid next year.(3) First-time generics receive 180 day exclusivity, meaning that other approved Cubicin generics may enter the market from the start of 2017.

Now I realise that a 2016 patent expiry still doesn’t tally with what we were told in 2013 but a published Agila WIPO patent (Priority Date August 23, 2012) for an improved daptomycin injectable formulation with TPM seems to put the matter beyond doubt. The patent document also clarifies the benefits of TPM in the daptomycin formulation - improved reconstitution time and increased stability of the reconstituted formulation at room temperature. (Daptomycin is supplied as a sterile, preservative-free, lyophilised 500- or 350-mg cake that must be reconstituted with normal saline prior to use).

Specifically, with respect to reconstitution time

As compared with the RLD (Cubicin) marketed formulation the present invention possesses various advantages. Soak time of about 10 minutes as specified in the RLD label is not required; the product of the present invention can be directly reconstituted with a vehicle with a reduced reconstitution time of not more than 5 minutes as compared to soaking the product for 10 minutes followed by gentle rotation or swirling the vial contents for few minutes for complete dissolution. (4)

Specifically, with respect to stability

Unexpectedly, combining daptomycin with TPM showed enhanced chemical stability of daptomycin in reconstituted solution at different temperature conditions such as room temperature (25°C) and at 2-8°C. At room temperature, the reconstituted solution of the present invention was found to be stable for up to 24hours in contrast to the innovator product which needs to be used within 12 hours of reconstitution when stored at room temperature. Further, at 2 to 8°C the reconstituted solution of the present invention was found to be stable for up to 72 hours in contrast to the innovator product which needs to be used within 48 hours of reconstitution when stored at 2 to 8°C. (4)

1. http://hotcopper.com.au/threads/injectable-antibiotic.2339330/page-12?post_id=13834694#.VXfljM-qpBc
2. http://www.fiercepharma.com/story/did-merck-pay-3b-too-much-cubist-analysts-weigh-impact-cubicin-patent-loss/2014-12-09
3. https://www.optumrx.com/vgnpreview/HCP/Assets/RxNews/New Generics_Cubicin_2014-0917.pdf
4. http://www.google.com/patents/WO2014045296A2?cl=en
   
   http://www.drugs.com/availability/generic-cubicin.html