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Pegasys vs PegIntron

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  • claudine intexas
    Pegasys vs PegIntron NATAP Reports ... Note: This is an excerpt from NATAP s Current Review of Hepatitis C . This following was written prior to the FDA
    Message 1 of 2 , Aug 21, 2001
      Pegasys vs PegIntron
      NATAP Reports
      ------------------
      Note: This is an excerpt from NATAP's "Current Review
      of Hepatitis C". This following was written prior to
      the FDA approval of Peg-Intron, and, as you all know,
      it was approved a couple of months ago now. Pegasys is
      still waiting approval.


      It is very difficult to compare two different drugs
      when studied in two separate studies. If you have a
      direct comparison in one study of the 2 drugs
      comparing them is easier but even this way can have
      problems. The results of a study can be affected by
      the precise methods or manner in which the mechanics
      of the study were carried out (Study Design). For
      example, if one study includes in there ITT analysis
      all patients who were randomized but did not receive
      drug the final % SVR will be lower than if patients
      such as that were not included. And there can be such
      differences between studies that we won't know about.
      Only the actual investigators and the company know
      that. When comparing the two Peg IFN/RBV studies the
      data presented by Schering and Roche are pretty close.
      The differences are not that much. However, these were
      the first Peg/RBV studies. Oftentimes as time goes by
      and more studies are conducted and as doctors get more
      experience using the drugs in the clinic we may be
      able to find differences in effectiveness between the
      2 PEGs.

      Review of Current Pegylated Interferon Data

      McHutchison reviewed at DDW 2001 the data on PegIntron
      monotherapy reported by Trepo at the EASL Spring 2000
      Conference. In a study of 1200 patients, the End-Of
      -Treatment Response (ETR) was 41%, 6 months after
      stopping therapy (Sustained Virologic Response- SVR)
      it was 23%. This compared to a 12% SVR in the control
      arm (standard IFN 3 MIU 3 times per week). The relapse
      rate was 39% and the discontinuation rate was 9-11%.
      Dose reduction rate was 15%. McHutchison concluded
      that PegIntron IFN monotherapy has similar side
      effects compared to standard IFN, double the Sustained
      Virologic Response, a similar relapse rate as standard
      IFN, and most genotypes 1 do not respond (14% vs 49%
      for genotype 2).

      At the same EASL Conference, Zuezem reported on 500
      patients randomized to receive either Pegasys once
      weekly or an induction regimen of standard IFN 6 MIU 3
      times per week for 12 weeks followed by the standard
      dosing of 3 MIU 3 times per week. Both studies were 48
      weeks of treatment followed by a 24-week follow-up
      period to evaluate SVR. The Pegasys ETR was 69%, the
      SVR was 38%. In the control arm the SVR was 19%, so
      again the Peg response was double that seen in the
      control arm. Genotype 1 SVR was 28% vs 64% for
      genotype 2. Patients with HCV viral load over 2
      million did not respond as well as patients with viral

      http://www.natap.org/2001/ddw/pegylated052301.htm

      What is sustained virologic response (SVR)?

      Treatment for HCV is generally 48 weeks, or perhaps 24
      weeks. The percent with undetectable virus ( 2 million
      viral load; Manns reported cirrhosis 10% in each group
      at AASLD, but at EASL 2001 reported 40-44% had
      "bridging fibrosis or cirrhosis" (F3/F4) while the
      Schering printed literature said liver biopsy by local
      pathologist reportd 28-30% (F3/F4).

      PegIntron/RBV (full dose 1.5 ug/kg) combined with
      800mg RBV showed an overall 54% SVR. Patients
      receiving standard IFN with 1000-1200mg RBV had a 47%
      SVR. 42% for genotype 1 vs 82% genotype 2/3 (ITT
      analysis). Patients with less advanced liver disease
      tend to respond better to treatment, so this should be
      a factor considered in deciding when to begin therapy.
      Manns reported that lower baseline fibrosis scores
      were associated higher SVR rates, a trend that has
      occurred in previous studies. When comparing patients
      with F1/F2 to F3/F4 fibrosis scores there was a
      difference in SVR of 5-7 percentage points.

      PegIntron/RBV Study ----- SVR
      PegIntron/ 800 mg RBV --- 54%
      IFN/RBV 1000/1200mg ------ 47%
      Peg/RBV Genotype 1 ------- 42%
      IFN/RBV Genotype 1 ------- 33%
      Peg/RBVGenotype 2/3 ------ 82%
      IFN/RBV Genotype 2/3 ----- 79%
      These data are Intent-to-treat (ITT) rather than
      as-treated analysis, which is more accurate.

      To read full PegIntron reports from EASL:

      http://www.natap.org/2001/36theasl/part4easl050101.htm


      http://www.natap.org/2001/36theasl/part5easl050101.htm


      Suggested Dosing of Ribavirin by Weight

      It was reported at AASLD (November 2000) from the
      PegIntron/RBV study that dosing ribavirin by weight
      may improve response to therapy, but this is
      controversial. These data had limitations. Study
      investigators did a retrospective analysis to see how
      much RBV concentration patients were receiving based
      on their body weights. To be clear, study patients
      were not randomized to different doses of RBV, as
      everyone received 800 mg per day of ribavirin. In the
      AASLD reported study, the authors reported patients
      with higher concentrations of RBV had better virologic
      responses: patients who had 85 kg had a 49% SVR. But,
      Manns concluded weight adjusted dosing of ribavirin
      with peginterferon alfa 2b will be confirmed in
      prospective studies. Two reasons for the controversy
      is that patients with lower weight tend to respond
      better to therapy and all patients in this received
      the same RBV dose of 800 mg at baseline. Schering is
      now conducting a large prospective study to address
      this question in which patients are receiving
      different RBV dosing based on weight.

      Therefore, Schering recommends the optimum Ribivarin
      dosing with Peg IFN a-2b
      1.5 ug/kg (10.6 mg per kilogram):

      85 kg = 1200 mg/day

      European authorities approved PegIntron with weight
      based dosing of ribavirin. The US FDA has not yet
      announced whether weight based dosing will be approved
      when PegIntron receives it's FDA approval. Pegasys
      studies have not yet analyzed or explored response by
      weight based dosing of RBV, but studies are expected
      to be exploring this. Data should be forthcoming soon.


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    • claudine intexas
      This is a re-post from Aug. 2001 Both Schering s PegIntron and Roche s Pegasys have now been approved, alone and with ribavirin. Pegasys vs PegIntron NATAP
      Message 2 of 2 , Mar 9, 2003
        This is a re-post from Aug. 2001
        Both Schering's PegIntron and Roche's Pegasys have now been approved,
        alone and with ribavirin.

        Pegasys vs PegIntron
        NATAP Reports
        ------------------
        Note: This is an excerpt from NATAP's "Current Review
        of Hepatitis C". This following was written prior to
        the FDA approval of Peg-Intron, and, as you all know,
        it was approved a couple of months ago now. Pegasys is
        still waiting approval.


        It is very difficult to compare two different drugs
        when studied in two separate studies. If you have a
        direct comparison in one study of the 2 drugs
        comparing them is easier but even this way can have
        problems. The results of a study can be affected by
        the precise methods or manner in which the mechanics
        of the study were carried out (Study Design). For
        example, if one study includes in there ITT analysis
        all patients who were randomized but did not receive
        drug the final % SVR will be lower than if patients
        such as that were not included. And there can be such
        differences between studies that we won't know about.
        Only the actual investigators and the company know
        that. When comparing the two Peg IFN/RBV studies the
        data presented by Schering and Roche are pretty close.
        The differences are not that much. However, these were
        the first Peg/RBV studies. Oftentimes as time goes by
        and more studies are conducted and as doctors get more
        experience using the drugs in the clinic we may be
        able to find differences in effectiveness between the
        2 PEGs.

        Review of Current Pegylated Interferon Data

        McHutchison reviewed at DDW 2001 the data on PegIntron
        monotherapy reported by Trepo at the EASL Spring 2000
        Conference. In a study of 1200 patients, the End-Of
        -Treatment Response (ETR) was 41%, 6 months after
        stopping therapy (Sustained Virologic Response- SVR)
        it was 23%. This compared to a 12% SVR in the control
        arm (standard IFN 3 MIU 3 times per week). The relapse
        rate was 39% and the discontinuation rate was 9-11%.
        Dose reduction rate was 15%. McHutchison concluded
        that PegIntron IFN monotherapy has similar side
        effects compared to standard IFN, double the Sustained
        Virologic Response, a similar relapse rate as standard
        IFN, and most genotypes 1 do not respond (14% vs 49%
        for genotype 2).

        At the same EASL Conference, Zuezem reported on 500
        patients randomized to receive either Pegasys once
        weekly or an induction regimen of standard IFN 6 MIU 3
        times per week for 12 weeks followed by the standard
        dosing of 3 MIU 3 times per week. Both studies were 48
        weeks of treatment followed by a 24-week follow-up
        period to evaluate SVR. The Pegasys ETR was 69%, the
        SVR was 38%. In the control arm the SVR was 19%, so
        again the Peg response was double that seen in the
        control arm. Genotype 1 SVR was 28% vs 64% for
        genotype 2. Patients with HCV viral load over 2
        million did not respond as well as patients with viral

        http://www.natap.org/2001/ddw/pegylated052301.htm

        What is sustained virologic response (SVR)?

        Treatment for HCV is generally 48 weeks, or perhaps 24
        weeks. The percent with undetectable virus ( 2 million
        viral load; Manns reported cirrhosis 10% in each group
        at AASLD, but at EASL 2001 reported 40-44% had
        "bridging fibrosis or cirrhosis" (F3/F4) while the
        Schering printed literature said liver biopsy by local
        pathologist reportd 28-30% (F3/F4).

        PegIntron/RBV (full dose 1.5 ug/kg) combined with
        800mg RBV showed an overall 54% SVR. Patients
        receiving standard IFN with 1000-1200mg RBV had a 47%
        SVR. 42% for genotype 1 vs 82% genotype 2/3 (ITT
        analysis). Patients with less advanced liver disease
        tend to respond better to treatment, so this should be
        a factor considered in deciding when to begin therapy.
        Manns reported that lower baseline fibrosis scores
        were associated higher SVR rates, a trend that has
        occurred in previous studies. When comparing patients
        with F1/F2 to F3/F4 fibrosis scores there was a
        difference in SVR of 5-7 percentage points.

        PegIntron/RBV Study ----- SVR
        PegIntron/ 800 mg RBV --- 54%
        IFN/RBV 1000/1200mg ------ 47%
        Peg/RBV Genotype 1 ------- 42%
        IFN/RBV Genotype 1 ------- 33%
        Peg/RBVGenotype 2/3 ------ 82%
        IFN/RBV Genotype 2/3 ----- 79%
        These data are Intent-to-treat (ITT) rather than
        as-treated analysis, which is more accurate.

        To read full PegIntron reports from EASL:

        http://www.natap.org/2001/36theasl/part4easl050101.htm


        http://www.natap.org/2001/36theasl/part5easl050101.htm


        Suggested Dosing of Ribavirin by Weight

        It was reported at AASLD (November 2000) from the
        PegIntron/RBV study that dosing ribavirin by weight
        may improve response to therapy, but this is
        controversial. These data had limitations. Study
        investigators did a retrospective analysis to see how
        much RBV concentration patients were receiving based
        on their body weights. To be clear, study patients
        were not randomized to different doses of RBV, as
        everyone received 800 mg per day of ribavirin. In the
        AASLD reported study, the authors reported patients
        with higher concentrations of RBV had better virologic
        responses: patients who had 85 kg had a 49% SVR. But,
        Manns concluded weight adjusted dosing of ribavirin
        with peginterferon alfa 2b will be confirmed in
        prospective studies. Two reasons for the controversy
        is that patients with lower weight tend to respond
        better to therapy and all patients in this received
        the same RBV dose of 800 mg at baseline. Schering is
        now conducting a large prospective study to address
        this question in which patients are receiving
        different RBV dosing based on weight.

        Therefore, Schering recommends the optimum Ribivarin
        dosing with Peg IFN a-2b
        1.5 ug/kg (10.6 mg per kilogram):

        85 kg = 1200 mg/day

        European authorities approved PegIntron with weight
        based dosing of ribavirin. The US FDA has not yet
        announced whether weight based dosing will be approved
        when PegIntron receives it's FDA approval. Pegasys
        studies have not yet analyzed or explored response by
        weight based dosing of RBV, but studies are expected
        to be exploring this. Data should be forthcoming soon.


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