Differences between Telaprevir & Boceprevir

[HectorSF]

I thought that some may be interested in the pros and cons of each DAA.
Hectorsf

Highlights From The FDA Advisory April Meeting;

Telaprevir
1-The cure rate for new patients taking telaprevir ranged between 75 and 79 percent, compared with 60 and 65 percent for boceprevir.

2-Most panelists said that patients who had previously failed treatment could likely achieve a cure within six months — half the time needed with older drugs — when taking telaprevir

3-As for Merck's drug Boceprevir those same patients would likely need a full year's worth of treatment with triple therapy. 4-Vertex executives said they were exploring a twice-daily regimen of telaprevir.

5-The agency said the risks of telaprevir were associated with skin reactions, such as rash, and anemia. The main safety concern discussed by the panel was severe rashes in a small number of patients, including three suspected cases of Stevens-Johnson Syndrome, a life-threatening outbreak of blisters. Vertex said the rashes disappeared when telaprevir was stopped.
Panelists urged Vertex to warn about the problem and tell doctors and patients how to spot a serious rash and when to stop treatment if needed.
Vertex offered rashes were managed in most patients with antihistamines and topical corticosteriods

Boceprevir
1-Mentioned by the panel is the concern for the complexity of prescribing the new Hepatitis C drug. The other concerns are safety, risk, and resistance variance.

2-Labeling; The panelists were split on using boceprevir in (null responder) patients. These patients were not included in Phase III trials, therefore no data is available. Also raised was the concern over the labeling allowing for treatment in advanced liver damage; Grade 3 Stage 4 patients.

3-Longer treatment duration was discussed in the difficult to treat patients; African Americans, patients with liver damage and for those people who have failed prior standard therapy.

4-Members of the FDA panel appeared to support shorter treatment for patients who show early responses to boceprevir.

5-Boceprevir's main risk is blood disorders such as anemia, a lack of red blood cells that causes fatigue and other symptoms, FDA reviewers said. Panelists said the problems needed monitoring but were manageable and usually not severe.

6-Some voiced concern that patients would find it challenging to stick with the three-times-a-day dosing for boceprevir on top of the two older medicines. (PEG-IFN plus RBV)

[HectorSF]

Thanks for the clarification and corrections. I should have verified before posting. I have a itchy tigger finger. Think before shooting!

....The package insert will be in 2 point type. It will include a magnifying glass and blotter Tylenol for the headache you'll get if you read it. ha ha

Cheers!
Hectorsf

[willing]

good summary but a couple of details don't look right. The actual response rates confirmed by the FDA are in the staff review summaries. For boce:

http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/Drugs/AntiviralDrugsAdvisoryCommittee/UCM252341.pdf

and for tela

http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/Drugs/AntiviralDrugsAdvisoryCommittee/UCM252561.pdf

For boce's P05216(SPRINT-2) the staff summary (Table 1) gives 63 and 66. In the tela 108(Advance) arm response was 79 and for trial 111(ILLUMINATE) the FDA staff report states 72. So the spread is 63-66 to 72-79; on phase III data  tela definitely  comes out ahead.

Both boce and tela tested shortened response-guided-therapy. Boce  included an RGT arm among tx failures  in its phase III trials. Tela did not but applied  for approval based on after the fact analysis and simulation.

Since boce is now approved, the question is settled by the package insert which states (Table 1) "Complete three-medicine regimen at TW36." so 4w lead in +32w of triple. Among those who cleared after 4w of boce, RGT yielded and 89% SVR rate whereas continuing to 48w improved that to 97%.

Tela  will likely get  also approval for RGT for relapsers (FDA was sympathetic). If so this would be a shorter 24w but actual data on outcome is not available.

The issue of boce use among null responders is also settled by the (31-page! - how are they gonna fit that into the pill box?) package insert, They wisely left it to the Dr's discretion:

"Response-Guided Therapy was not studied in subjects who had less than a 2-log10 HCV-RNA decline by treatment week 12 during prior therapy with peginterferon alfa and ribavirin. If considered for treatment, these subjects should receive 4 weeks of peginterferon alfa and ribavirin followed by 44 weeks of VICTRELIS 800 mg orally three times daily (every 7-9 hours) in combination with peginterferon alfa and ribavirin."

[SusieS2010]

Thanks for this Hector. Anything that makes it easier to understand is always appreciated.