Tykerb not effective in treatment of prostate cancer

Like many other drugs before it, lapatinib (Tykerb/GlaxoSmithKline) appears to have very limited clinical activity in prostate cancer according to a recently published report.

Sridhar et al. have published data from a multicenter, Phase II clinical trial of lapatinib in 23 patients with early stage, recurrent, but hormonally untreated  prostate cancer or metastatic disease. All eligible patients received a daily, oral dose of lapatinib 1500 mg until progression. The primary end point of this study was PSA response.

The 23 eligible patients had a median age 67, a mean baseline PSA level of 7.5 ng/ml , and a “performance status” of 0-2 (based on the Eastern Cooperative Oncology Group or ECOG criteria). Results reported include the following:

  • There were no PSA responses.
  • Median time to progression was 4.6 months
  • Progression-free survival was estimated to be 44.5 percent at 6 months.
  • Commonly observed adverse effects included lymphopenia, fatigue, rash, dyspepsia, and diarrhea.
  • More serious adverse events included 2 cases of significantly elevated alanine aminotransferase levels, and very blurry vision in 1 patient.

Despite the fact that the investigators seem to have given lapatinib its “best shot” by trying it relatively early on in some patients who had never received hormone therapy, the accumulating evidence appears to support data from earlier studies in suggesting that the tyrosine kinase inhibitors that target epidermal growth factors 1 and 2 may have little to no activity in patients with prostate cancer.

2 Responses

  1. I am currently enrolled in this trial, but have not yet received lapatinib. This is introduced after 4 weeks.

    Since the results are rather discouraging, will the trial be canceled or will patients be given alternative treatments?

  2. Dear Tom:

    That’s a question you’d have to ask your doctor. According to the trial information on ClinicalTrials.gov, no further patients will be enrolled into this trial.

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