Sunday, June 22, 2008

Cervical cancer vaccines

The UK has recently approved a second vaccine that protects against HPV called Cervarix from GSK, in addition to Gardasil from Merck. Both vaccines protect against HPV, but Gardasil also protects against gentical warts, which Cervarix does not.

Genital warts on a maleMale with genital warts - image courtesy of Wikipedia

The wholesale price for the two is exactly the same, £80.50, and the formal list price is also comparable at £240 per vaccination. Other European countries appear to have chosen Gardasil, for it's extra protective effects. Genital warts are, of course, far more common than cervical cancer in Western Europe. Most women over 40 receive a regular annual Pap smear to screen for HPV and cervical cancer, hence the low rates compared to Latin America and Africa, where the smear test is considerably less common.

Guess which vaccine the NHS chose in it's wisdom? Yes, Cervarix. Any parent wanting to innoculate their daughter with Gardasil will therefore have to get it on private health plans at a much greater cost.

Meanwhile, although a small number of boys were included in the trial, there were insufficent numbers to gain approval for use in the male population. If you are going to reduce the spread of genital warts and HPV in the population, it makes sense to innoculate both surely?

Zemanta Pixie

Wednesday, June 11, 2008

Are Her2 inhibitors an alternative to chemo in breast cancer?

Herceptin Fab (antibody) - light and heavy chainsImage via WikipediaSeveral studies exploring the use of lapatinib (Tykerb, GlaxoSmithKline) in metastatic breast cancer have suggested that it may offer an alternative to chemotherapy in this setting, both as monotherapy, and in combination with other targeted therapies.

One study explored the use of lapatinib alone, whereas others investigated combinations with trastuzumab (Herceptin, Genentech/Roche), with bevacizumab (Avastin, Genentech/Roche), and with the investigational agent pazopanib (under development by GlaxoSmithKline).

Studies presented at American Society of Clinical Oncology opened up an interesting debate regarding whether biological therapy without chemotherapy for metastatic breast cancer is feasible.

The efficacy of these targeted agents is higher when they are combined with chemotherapy, and the toxicity of these agents in combination needs to be explored further. Hence, the preferred front-line choice for metastatic breast cancer is presently trastuzumab with chemotherapy, and the evidence suggests that continuation of trastuzumab is the best option for patients who progress. Combining drugs that have different targets is also a promising option.

Lapatinib is currently approved in the US for a very narrow indication in combination with capecitabine (Xeloda, Roche) for advanced metastatic HER2+ breast cancer in women who have received previous chemotherapy, including an anthracycline, a taxane, and trastuzumab. A similar approval in Europe is pending with the EMEA.

The largest of the new trials presented was a phase 3 study of lapatinib monotherapy compared with a combination of lapatinib and trastuzumab (EGF104900). Both of these drugs target HER2+ breast cancer, but trastuzumab (a monoclonal antibody) is a large-protein molecule that targets the part of the HER2 protein on the outside of the cell; lapatinib (an oral drug) is a smaller molecule that enters the cell and blocks the function of this and other proteins intracellularly. The combination effectively attacks HER2 from multiple angles.

The trial involved 269 patients with HER2+ breast cancer who had documented progression on trastuzumab in the metastatic setting. The combination of lapatinib plus trastuzumab showed a significant increase in progression-free survival, compared with lapatinib alone (12 weeks vs 8.1 weeks). This translates into a 27% reduction in the risk for disease progression (hazard ratio [HR], 0.73; P = .008). The overall clinical-benefit rate (the response rate and the rate of durable stable disease) for the combination was double that for monotherapy (24.7% vs 12.4%; P = .01). There was a trend toward improved overall survival.

More data on the role of combined HER2+ therapy in combination with chemotherapy will be available soon from the ongoing ALTTO (Adjuvant Lapatinib and/or Trastuzumab Treatment Optimization) study. ALTTO is being conducted in less-heavily pretreated patients with early-stage disease.

A trial of lapatinib plus bevacizumab was reported in a small phase 2 single-group study, conducted in 32 patients who had received a median of 5 previous metastatic breast cancer therapies. 28 of these 32 patients had received prior treatment with trastuzumab.

The combination resulted in a 34.4% clinical-benefit rate (defined as complete response plus partial response plus stable disease at 24 weeks or more), and 62.5% of patients were progression free at week 12.

The most common adverse events were diarrhea (81%), rash (66%), nausea (56%), fatigue (56%), and vomiting (46%). There were 2 grade 2 asymptomatic LVEF decreases, 1 grade 3 gastrointestinal hemorrhage, and 1 grade 3 hypertensive event.

Overall, blocking both the HER2 and the VEGF pathways led to anticancer activity for even heavily pretreated patients with metastatic breast cancer that could potentially advance the treatment of this high-risk disease.

A combination study of lapatinib plus pazopanib, where both drugs were taken orally once daily, suggested that they might provide a potential future treatment option for HER2+ breast cancer. It involved 141 patients and compared the combination with lapatinib monotherapy.

The results confirmed the efficacy of lapatinib monotherapy and showed a trend toward better outcomes with the combination. At 12 weeks, 36.2% of patients taking the combination and 38.9% taking the monotherapy experienced disease progression (P=.37). The response rate was 44.9% with the combination and 28.8% with the monotherapy according to investigator assessment, and 36.2% vs 22.2%, respectively, according to independent assessment.

Monday, June 2, 2008

Erbitux extends overall survival by 5 weeks in lung cancer

announced that late-stage study data showed that first-line treatment with Erbitux (cetuximab) plus standard chemotherapy significantly increased overall survival by about five weeks in patients with advanced non-small cell lung cancer (NSCLC), compared with chemotherapy alone. The results were presented at the American Society of Clinical Oncology (ASCO) meeting this weekend.

To put things in context, the American Cancer Society estimates that in the United States, more than 215,000 people will be diagnosed with lung cancer in 2008, which accounts for about 15 percent of all cancer diagnoses. Approximately 87 percent of these patients will be diagnosed with NSCLC, with many being diagnosed with locally advanced or metastatic disease. Lung cancer is the leading cause of cancer-related death in men and women, with more than 161,000 deaths expected to occur in 2008 – accounting for about 29 percent of all cancer deaths. In 2008, it is estimated that more Americans will die from lung cancer than breast, prostate, and colorectal cancers combined. Studies showing a significant improvement in survival will therefore impact the course of disease and affect large numbers of patients.

The randomised FLEX study involved 1125 patients with advanced non-small cell lung cancer (NSCLC) who had not previously received chemotherapy. The data demonstrated that those who received ImClone announced that Erbitux combined with chemotherapy resulted in a median overall survival of 11.3 months, compared with 10.1 months for chemotherapy alone, a significant difference. The findings also showed that tumours shrank in 36.3 percent of patients who received the Erbitux regimen, compared with 29.2 percent of patients who only received standard chemotherapy.

It is unlikely that the findings are impressive enough to significantly affect the position of Genentech's Avastin for patients with lung cancer who can be treated with the product in the short term. However, doctors treating patients with NSCLC who cannot take Avastin may opt to prescribe Erbitux, which could lead to an additional $700 million in annual sales in the US.

Overall, probably one in five patients or less get Avastin, so there's a huge opportunity outside of that in the long run, and the data are very competitive. Erbitux is expected to be filed for expanded US approval in NSCLC in the second half of this year, and the new indication could be added to the label by mid-2009. If approved, this will open new first-line treatment options for patients with non-small cell lung cancer regardless of histological subtypes, and potentially set a new standard in the first-line treatment of this disease.