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Boston Scientific Corporation Message Board

  • bridgeofsighs2001 bridgeofsighs2001 Nov 8, 2004 2:30 PM Flag

    FDA meeting Cypher Oct. 2002

    http://www.fda.gov/cdrh/PDF2/P020026b.PDF
    Talks about cracking of the top coat and Cypher shelf life. This document explains the polymer in detail.

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    • OK. As far as future agreements go, I can only say that SRDX consistently states each quarter during their conference call that they still are moving ahead on development work for the next two generation of Cypher. To be fair, I have not heard JNJ verify this. I guess Cordis could be stringing them along, but at significant cost. At the least, if Cordis were planning to dump SRDX, then why continue to pay for development work? My conclusion is that as long as this paid development work proceeds, SRDX is still a major contender. Or, perhaps the development work SDRX is doing for future generations of Cypher uses another one of their drug-eluting polymer systems, or drops the top coat? Nobody has said (to my knowledge) that future generations of Cypher will use the same polymer. Anyhow, like I said, I'm not worried until I see something more informative than rumors. Maybe I should be. Time will tell.

    • aslan, I can�t disagree or argue with the chronology of events you describe, re: the souring relationship between Cordis / SRDX. I can only tell you what the technical guys are grumbling (or willing to grumble to an outsider), but admit they are not the decision makers. If the agreement includes future DES projects (which they disagree) and they are unhappy with the present one (regardless of whose fault it is), wouldn�t you expect Cordis to merely go through the motions, re: the agreement, and forge ahead elsewhere ?

    • Foolish, isn't that just semantics? If friction was lower, whould that not reduce the withdrawl forces? To my knowledge, balloon stickyness is not a big issue with Boston's bare metal stent of the same design. Sure, a different strut design may help prevent sticking, but on Taxus Express 2 it would seem that the polymer is the culprit. I'm happy to entertain arguments to the contrary though. This is a good discussion.

      Thanks for the links.

    • Slides 31 and 32 in Dr. Stone's "next generation" presentation are presumably what endoqd is refering to as suggesting that stickiness is not caused by the polymer:

      http://www.tctmd.com/expert-presentations/table-2.html?product_id=7847&sort_key=
      31&ppt_slide_id=116286


      This may well prove to be true, but it is worth pointing out that it is at odds with the FDA's subsequent (although probably written around the same time) article:

      http://finance.messages.yahoo.com/bbs?.mm=FN&action=m&board=7076649&tid=bsx&sid=
      7076649&mid=34290


      "... it seems to result from a combination of patient-related and device-related factors. These factors are still under review but are currently presumed to include friction between the stent-delivery balloon and the drug-polymer coating on the stent, as well as certain characteristics of the coronary vessel."

    • I hate to keep correcting you...BUT...as for Taxus, the struts are covered with the polymer silly, and the balloon doesn't stick to bare metal. Since the Translute polymer is essentially Butyl Rubber, it's hard to imagine that a baloon would easily glide across that surface after being pressed against it at high pressure! Do you remember the following data?

      "Non-uniform paclitaxel-eluting stent coating and unexpected balloon-stent stickiness: Any concern with routine practice?"

      Dr. G�rard Finet, Dr. Gilles Rioufol, and Dr. Martine Gilard wrote:

      "Since Taxus Express 2 stent has been routinely used in our institution, we have experienced difficulties withdrawaling the balloon after stent deployment. For better knowledge of DES(drug-eluting stents), we performed a bench and optical microscopy observation with one Cypher Select and two Taxus Express 2 from two cath labs (Lyon and Brest). Balloon deflation is similar between stents (crossing profile 1.7 mm both), but only Taxus stent remains hanged on, and it is obviously sticky. By optical microscopy we observed only for Taxus stent that the coating is unstructured by the meshes sticking to one another. Coating is non-uniform with
      numerous smears especially around the bridges.

      We conclude that:
      1. Paclitaxel-coating is sticky and non-uniform leading to mechanical difficulties after stent implantation,
      2. Paclitaxel local concentration may vary within stent, and
      3. Manufacturer quality control is questioned."

    • endoqd, that's an interesting threory that Cordis is unhappy with Surmodics, but coming from a message board it should be taken with a pound of rock-salt. Can you back it up?

      Cordis continues working with SRDX on the next two generations of DES, and in fact, SRDX spends so little on marketing because companies literally come to their door wanting to work with them. That is why the non-Cordis revenue stream is building.

      SRDX got screwed by Cordis: first Cordis demands to do the manufacturing in house instead of allowing SRDX to do contract coating work as planned, for which they were apparently building a nice new facility (the Bloomington facility, which is now up for sale). Then Cordis somehow re-negotiates a dismal royalty rate with SRDX that includes a step DOWN feature and SRDX accepts it, along with an agreement for exclusive use of SRDX's polymer system on cardiac DES with all rapalogues! (perhaps this is why SRDX changed management ;). On top of that, Cordis screws up manufacturing, and "adulterates" the stents. You can't blame SRDX for that. The tiny cracks originally seen in the top coat were not a problem. Besides, who's bad idea was the top-coat to begin with? If you have connections, please ask them and get back to me.

    • Bridgeofsighs� I forgot about the SS&E. Thanks for reminding us. At the risk of sounding ungrateful, the news of Cypher cracking is old. What�s really interesting now (w/ 7 months hindsight since Cypher tagged �adulterated�, re: un-validated coating, etc. http://www.fda.gov/foi/warning_letters/g4601d.htm) is the omen foretold by the �cracking� and �delamination� that Cordis downplayed in the PMA (p. 12). FDA won't make this mistake again as they too look foolish on this point.

      It�s even more interesting that the coating process remains un-validated to this day (elution testing continues to fail for units > 3 months). Word is Cordis has given up on ever fixing the problem, and is looking to keep Cypher alive long enough to move onto its next gen.-DES (without SRDX w/ whom they are disgusted). Of course, any such change requires bench and animal testing, and a full clinical trial so the situation will remain this way for several years.

      It�s also interesting to note on p. 7, Cordis did not run the full battery of ISO-10993 biocompatibility testing prior to approval. The SS&E concluded that the �long-term biocompatibility of [Cypher] is unknown�. Invest91765 recently asked if Cypher might cause late tissue inflammation, and right now it can be said that nobody knows.

    • Uhhhh...

      Does anyone know if the cracking and subsequent flaking enter a patients bloodstream? And if it does is there a health risk associated with that stuff in your bloodstream?

    • bridge:

      Nice post.

      I haven't had a chance to look closely but the one passage which jumped out is:

      "* Note: Stress cracks were observed in the coatings of all samples both pre- and postfatigue
      analysis. Cracks increased in length and width throughout the duration of testing.
      SEM also showed that changes to the coating surface occur after expansion. The sponsor
      performed post-fatigue analysis and concluded that the likelihood of particle embolization
      would be minimal. The phenomenon of delamination of the coating from the stent struts
      was also noted in several of the animal studies. However, evaluation of the clinical studies
      provided to support the application did not reveal any negative sequelae that might have
      arisen from the compromise of coating integrity."

    • So, Endoqd wasn't a rumormonger as Foolish charged?

      Knowledge of Cypher cracking has been out since 2002. Looks like it might have been a bigger deal to the FDA than JNJ had hoped.

      Can anyone dig up the April warning letter from the FDA to JNJ? I'd like to read it again. I can never navigate the fda site.
      Thx in advance.

      • 1 Reply to jokerswild41s
      • joker:

        <"So, Endoqd wasn't a rumormonger as Foolish charged?">

        Rumours are often distortions of the truth. The issue with REGTEK's posts was his hiding behind different aliases to spread his message. I discounted what he said because of his dishonesty, not because of his message - which, by the way, was to say that polymer cracking is behind Cordis' CURRENT manufacturing dificulties. Cracking might be the current issue, but everything we have turned up so far predates approval of Cypher.

 
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