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Vertex Pharmaceuticals Incorporated Message Board

  • orangenation5 orangenation5 Aug 5, 2008 8:53 PM Flag

    Basic Question On SGP Data

    Hey everyone,

    Been looking at VRTX for awhile, and finally bit today. Doing my DD for sometime now, and fully admit I'm not an expert in this field, so I apologize for the lamen question upfront...

    I noticed in the SGP PR (linked below for easy reference) that there are 595 patients. When I add up the denominators though in the "treatment arms" table, I come up with only 520 people. Now, I know ITT means anyone who took at least a single dose, so why does the data not add up to 595?? Where are the other 75 people? Did they just sign up, and not take a dose (my attempt at humor)?

    Thanks!

    http://biz.yahoo.com/prnews/080804/nym051b.html?.v=1

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    • I made an impotant typo in the above post, for which I apologize. The third paragraph should read:

      Dew keeps raising the fact that the two 28 week treatment arms add to 210. This is true and at best a confusion on his part, at worst a deliberate red herring. That the two 28 week arms add to 210 is simply a coincidence to the fact that the recent press release shows the the two no-lead in arms as also adding to 210. This can easily be seen in the chart here:

      My mistake was neglecting to type the no in front of lead-in in the third sentence. The conclusions and logic remain.

    • Justrpaul,

      Thanks for the clarification....in trying to follow DD and everyone else's argument it was not clear that the number 210 was coincidentally the same. Whether it was a deliberate head fake on DD's part?.....who knows?

      "No word can sooth him, no prayer remove him"

    • Stop making accusations against me and others. I have done no such thing, I have posted numbers that you continually spin and distort.

      "During a late-breaker oral presentation at EASL, Dr. Kwo presented interim results for the two 28-week boceprevir arms of the study. For patients receiving 4 weeks of PEGINTRON and REBETOL therapy prior to the addition of boceprevir, SVR 12 was 57 percent (59/103), compared to 55 percent (59/107) for patients in the boceprevir triple combination arm. For patients in these two boceprevir arms who had undetectable virus (HCV-RNA) after 4 weeks of boceprevir treatment (RVR), the SVR 12 rates were 86 percent (53/62) and 74 percent (31/42), respectively. SVR 12 rates are not yet available for patients in the 48-week boceprevir arms or the 48-week control arm, as treatment of these patients is ongoing."

      The PR CLEARLY SHOWS 2 ARMS ONLY-ONE HAS LEAD IN THE OTHER IS TRIPLE COMBO.

      http://www.easl.ch/easl2008/program/ViewAbstract.asp

      No Lead In shows 226 in the Abstract. Numbers add up to 595 with the 59 in the low riba arm.

      Treatment Arm All patients
      No P/R Lead-in 28 Weeks 55% (59/107)
      P/R Lead-in 28 Weeks 56% (58/103)
      No P/R Lead-in 48 Weeks 66% (68/103)
      P/R Lead-in 48 Weeks 74% (76/103)
      P/R Control 48 Weeks 38% (39/104)

      This shows ALL the Arms, shows 210 in the No Lead In Arms. WITH the 59 in the low riba arm, it adds up to 579.

    • here's a pdf of SGPs EASL presentation (I found it by googling boceprevir EASL) regarding SVR for the 28 week arms

      http://hivandhepatitis.com/2008icr/easl/pdf/KwoSPRINT.pdf


      slide 12 has the total discontinuation rates for the 28 week arms. Might make it easier for discussion instead of relying on PRs

      Any comments on whether the dropout rates would be lower or higher for the 48 week arms?

      • 1 Reply to jonnyhownow
      • Johnny,

        Thank you very much for posting this. It raises additional questions though.

        This is the only place that I have seen Schering present dicontinuation data for boceprevir in such detail. The two 28 week boceprevir arms aveage 27% total dropouts. That is really quite high and what is even more striking is that this is for the 28 week arms. You would expect the 48 week arms to have a higher or at least equivalent dropout rates. Yet the 48 week arms showed 74 and 66% SVR12. If you simply added the 28 week drop out average of 27% you would get 101% and 93%, leavng no or very little room for the patients who finished treatment but did not SVR.

        This discontinuation data and the missing 16 patients certainly raise a lot of questions about the Schering boceprevir data.

    • Not sure why you can't do math (or why you have to be so beligerant either).
      "Treatment Arm All patients
      No P/R Lead-in 28 Weeks 55% (59/107)
      P/R Lead-in 28 Weeks 56% (58/103)
      No P/R Lead-in 48 Weeks 66% (68/103)
      P/R Lead-in 48 Weeks 74% (76/103)
      P/R Control 48 Weeks 38% (39/104)
      "

      28 week group: 107+103= 210 correct?
      No Lead-In group: 107+103= 210 correct?

      http://www.easl.ch/easl2008/program/ViewAbstract.asp

      In that table, it shows the No Lead-In group to be 226 correct?

      Stop telling me and others to get a grip. WE are the only ones pulling data, you are just giving responses without showing data, and then getting an attitude with us. If you want to take it down the low road like you are, it only makes you look worse.

    • I said that about SVR12 vs. SVR24. Not sure why you needed to repeat it.
      As far as your last post, 210 adds up to the No lead in arms, but also, the table shows 210 for the 2 28 week arms. His math is fine.

    • Here's the PR from the AASLD meeting:

      http://www.schering-plough.com/schering_plough/news/release.jsp?releaseID=1135273

      "MILAN, Italy, April 26 /PRNewswire/ -- Schering-Plough Corporation (NYSE: SGP) today reported that results from a planned interim analysis of an ongoing Phase II study of boceprevir, its investigational oral hepatitis C protease inhibitor, in 595 treatment-naive patients with chronic hepatitis C virus (HCV) genotype 1 were presented at the 43rd Annual Meeting of the European Association for the Study of the Liver (EASL). The ongoing study evaluates boceprevir in 28-week and 48-week treatment regimens."

      Again, 595.

      They break down 2 arms of the trial, where the total numbers in those arms are the same, but they apparently had 1 patient with SVR12 that did NOT make it to SVR24:

      "During a late-breaker oral presentation at EASL, Dr. Kwo presented interim results for the two 28-week boceprevir arms of the study. For patients receiving 4 weeks of PEGINTRON and REBETOL therapy prior to the addition of boceprevir, SVR 12 was 57 percent (59/103), compared to 55 percent (59/107) for patients in the boceprevir triple combination arm. For patients in these two boceprevir arms who had undetectable virus (HCV-RNA) after 4 weeks of boceprevir treatment (RVR), the SVR 12 rates were 86 percent (53/62) and 74 percent (31/42), respectively. SVR 12 rates are not yet available for patients in the 48-week boceprevir arms or the 48-week control arm, as treatment of these patients is ongoing.

      Notice that in April, they reported 59/103 had SVR12, yet in the PR the other day, 58/103 had SVR24.

      Granted, this really has nothing to do with the issue at hand, but I noticed it when I was going through the PR. It kind of makes me wonder why some analysts feel the data released yesterday was a surprise, unless they were impressed with the 48 week data, because the 28 week data was actually 1 patient WORSE than in April. Or, unless they expected more not to make it to SVR24, which really shouldn't be, because a very high % that make it to SVR12 do get to SVR24-as is shown in this study also. It also PROBABLY explains why many analysts came out yesterday and reiterated prior comments about VRTX.

      This COULD BE why VRTX opened in the low 28's and quickly made a low below 28, and has risen since the open 2 days ago, to yesterday's close, and has recovered about 3.50 of that decline (which Dew rather happily pointed to as proof he is correct).
      It COULD BE that the market realized that the 28 week data was not anything new at all.

      edit: Looking at the stock chart from April, it doesn't appear the Abstract or this PR caused the stock to do what it did the other day. But at the time, VRTX had their own very positive trial news out, plus the VX-770 news.

    • Here is the top line of the press release:

      "KENILWORTH, N.J., Aug. 4 /PRNewswire-FirstCall/ -- Schering-Plough Corporation (NYSE: SGP - News) today reported top-line results from a planned interim analysis of a Phase II study of boceprevir, its investigational oral hepatitis C protease inhibitor. The analysis showed a high rate of sustained virologic response (SVR) in patients receiving boceprevir-based combination therapy in this study of 595 treatment-naïve patients with chronic hepatitis C virus (HCV) genotype 1."

      Notice it says 595 patients.

      Here is the text in the PR:

      "Treatment Arm All patients
      No P/R Lead-in 28 Weeks 55% (59/107)
      P/R Lead-in 28 Weeks 56% (58/103)
      No P/R Lead-in 48 Weeks 66% (68/103)
      P/R Lead-in 48 Weeks 74% (76/103)
      P/R Control 48 Weeks 38% (39/104)
      "

      It adds up to 520. There were 59 in the low dose Riba group, which don't matter for the purposes of the study, so 520+59 = 579.

      The top says 595, the numbers in the table plus those 59 come to 579, a difference of 16.

      http://www.easl.ch/easl2008/program/ViewAbstract.asp

      The abstract CLEARLY shows 226 in the No-Lead-In Group, the numbers in the PR add up to 210.

      I think anyone with any experience knows you have to be careful of what is put in PR's. In fact, an Abstract that will undergo analyst and scientist scrutiny at a major conference is more likely to be correct, and if it isn't, there would likely be a PR to correct any errors.

      Now, I always allow that there is another explanation for things, but the preponderence of evidence suggests that Paul and Glad have it correct (and they didn't resort to name calling either).

    • Just like the last publicity stunt by SGP, they used the same tactic this time. What they did then and what they did this time was to not count all the drop outs in their statistics. For example look at this sentence from their press release:

      "In the two 28-week boceprevir arms of the study, SVR at 24 weeks after the end of treatment (SVR 24) was 56 percent and 55 percent for patients in the lead-in and no lead-in arms, respectively."

      By "the end of treatment" they are talking about those who finished the treatment. They do not include all drop outs whereas VRTX counts at drop outs as failures and clearly says so in their reports. No such statement appears in any of SGP publications that I am aware of. I think the last time a lot of analysts and the so called gurues did not catch that before they started to mouth off that BOC was a comparator to TVR and some even said it may come to market at the same time as TVR.

    • Very interesting question. I think someone commented on this yesterday, but I can't remember who or in what thread.

      I did go to the abstract from thier presentation at EASL in April.

      http://www.easl.ch/easl2008/program/ViewAbstract.asp

      From that and the current press release, you can see two issues. One, they are no longer including 59 patients in a low RIBA arm. Nothing to be concerned there as the data is now clear that that doesn't seem to work. More interstingly though, there are 16 patients missing from the no lead-in arms. The new press release has a total of 210 between the two arms and the EASL abstract showed 226 combined in the two arms.

      You're right since it is an intention to treat analysis, those 16 patients should still be in there. Why not is a good question. I have no ieaa why, but my experience is that Schering tends to play some games in its PRs that it cannot get away with at scientific meetings.

      Just supposing those 16 were equally distributed between the two arms and they were not SVR, they would reduce the effective percentages from 55% to 51% in the 28 week arm and 66% to 61% in the 48 week arm. This is certainly speculation but those 16 patients should be accounted for and until they are any comparison with the telaprevir data is suspect.

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