18 september 2017: Lees ook dit artikel: https://kanker-actueel.nl/NL/immuuntherapie-met-provenge-spirutacel-t-geeft-betere-resultaten-op-overall-overleving-bij-gevorderde-prostaatkanker-als-deze-gevolgd-wordt-door-dendritische-celtherapie.html

3 oktober 2011: Bron: Medscape

Er zijn steeds meer twijfels over de waarde van Provenge in relatie tot de kosten van deze immuuntherapeutische behandeling voor uitgezaaide prostaatkanker. (Provenge is in principe een vorm van dendritische celtherapie gecombineerd met chemo). Dit meldt Medscape in een lang artikel. Er zijn verdere vergelijkingen gemaakt met de resultaten van andere middelen tegen prostaatkanker zoals bv abiraterone en een chemocombinatie met prednison. In beide gevallen liggen de resultaten niet erg ver uit elkaar. En verder zijn enkele medewerkers van Dendreon betrapt op fraude en oplichting en is Dendreon, het moederbedrijf van Provenge, hiermee in opspraak gekomen. Of dit allemaal waar is weet ik ook niet. Het is wel opvallend dat Medscape hierover breed uitpakt. Hier een citaat uit een lang artikel dat volledig te lezen is als u hier klikt.

Twijfels over Provenge en Dendreon

The recent problems with Provenge are the latest chapter in the history of struggles for this prostate cancer treatment, which include regulatory setbacks, questions about the quality of clinical trial data, and competing products in the treatment of mCRPC.

In 2007, the US Food and Drug Administration (FDA) deferred a decision on Provenge and requested more data because a phase 3 study (J Clin Oncol. 2006;24:3089-3094) failed to meet its primary end point — a significant increase in time to disease progression in men with asymptomatic mCRPC.

When the vaccine was finally approved by the FDA in 2010, clinical trial data demonstrated that the drug statistically significantly improved overall survival.

With a median follow-up of 36.5 months, men treated with Provenge (n = 341) had a median survival of 25.8 months, compared with men treated with placebo (n = 171), who had a median survival of 21.7 months.

This showed a 4.1-month median survival advantage for Provenge and a 24.1% reduction in the risk for death (hazard ratio, 0.759; P = .017).

However, the survival data were potentially confounded by the trial design, according to a federally sponsored independent report that accompanied the Centers for Medicare and Medicaid Services (CMS) review of the drug.

The report called into question the exact length of the survival benefit seen with Provenge, because the therapy was tested in conjunction with postprogression chemotherapy.

"The current existing analyses are insufficient to know to what degree sipuleucel-T is effective in the absence of chemotherapy, or [to what degree it] depends on chemotherapy to demonstrate improvement in survival," the report notes. The report was commissioned by the Agency for Health Research and Quality as part of the CMS review of Provenge, and was compiled by the Blue Cross and Blue Shield Association, Technology Evaluation Center evidence-based practice center in Chicago, Illinois.

Furthermore, Provenge was "not a home run," according to an expert who noted that its 4.1-month survival benefit is not largely different from that seen with the standard chemotherapy used in this setting, docetaxel (Taxotere, Sanofi-Aventis).

Docetaxel and prednisone demonstrated a 2.4-month survival advantage on average, compared with mitoxantrone and prednisone, in men with mCRPC (N Engl J Med. 2004;351:1502-1512).

At the time Provenge was approved, docetaxel was the only other approved treatment for men with mCRPC.

However, after its groundbreaking approval in 2010 — Provenge was the first immunotherapy approved by the FDA — a number of other therapies were approved in advanced prostate cancer, creating competition where little had existed previously.

Abiraterone (Zytiga, Johnson & Johnson) was approved by the FDA in April 2011; cabazitaxel (Jevtana; Sanofi-Aventis) followed soon after that, in June 2011. Both demonstrated a prolongation of survival in randomized clinical trials for patients with castration-resistant prostate cancer. Read more>>>>>


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