Thursday, May 28, 2009

Looking ahead to ASCO

As the 45th Annual Meeting of the American Society of Clinical Oncology (ASCO) looms, there is just time to look at the data and presentations that will be making the biggest impact. The 4,000 study abstracts for this years Meeting, to be held from 29th May to 2nd June, in Orlando, FL, have now been published, and have drawn a mainly disappointing response. However, there are some biotech companies that will be worth keeping an eye on.

One such company with positive results to present is OncoGenex Pharmaceuticals, whose investigational prostate cancer (PCA) drug, OGX-011, has produced promising Phase II results. Some analysts have commented that the data could be significantly better than Dendreon’s Provenge (sipuleucel-T). At the time results were submitted to ASCO, the preliminary median overall survival in patients with advanced PCA who were treated with OGX-011 plus docetaxel was 27.5 months compared to 16.9 months for patients treated with docetaxel alone. Final survival data as of April for this trial will be presented during the Meeting.

Another company to report encouraging results will be Exelixis, from a Phase II study of XL184 in patients with progressive glioblastoma multiforme. The drug is being co-developed with Bristol-Myers Squibb. In the trial, XL184 was shown to shrink brain tumours in some patients, according to interim results. At four weeks, 26 patients have been assessed. Ten of them (38 per cent) had tumour shrinkage of at least 50 per cent, including one patient who had a 100 per cent reduction in tumour size. Nine patients had tumour measurement changes ranging from 24 to -49 per cent and seven had at least a 25 per cent increase in tumour burden. Of 17 patients who had not received prior anti-angiogenic treatment, nine had at least a 50 per cent reduction in tumour burden.

OSI Pharmaceuticals will also create a lot of attention at the Meeting. The company will present data from two Phase III studies looking at the use of its drug Tarceva (erlotinib) as front-line maintenance therapy in patients with non-small cell lung cancer. OSI hopes that the data from the two studies, called SATURN and ATLAS (AVF3671g), will convince physicians to use the drug, which is co-marketed with Roche, more in the maintenance setting. However, results showed only a small gain over placebo in the time before disease progressed for certain lung cancer patients, leaving many onlookers less than impressed with the data.

Apart from these presentations, there seems little to get excited about. Roche will present data on the use of adjuvant Avastin (bevacizumab) in colon cancer, but the company has already disclosed the study's failure to produce a significant survival benefit. Results of that trial, known as C08, along with around 30 late-breaking studies will be unveiled at the Meeting, which will hopefully hold more surprises than the published abstracts.

Matthew Dennis - Editor, Cancer Drug News

Thursday, May 21, 2009

RCC: targeted therapies increase survival

The arrival of targeted therapies has dramatically improved outcomes for patients with renal cell carcinoma (RCC). With approvals of Bayer/Onyx Pharmaceuticals' Nexavar (sorafenib), Pfizer's Sutent (sunitinib), Novartis' Afinitor (everolimus) and Wyeth's Torisel (temsirolimus), doctors now have a anumber of agents to choose from to treat patients.

However, due to the fact that in subjects with advanced RCC, who are receiving therapy, their disease will ultimately progress, physicians must choose from the drugs available to best extend survival whilst preserving quality of life. This requires consideration of the overall treatment plan from the outset, so that when selecting which agent to start treatment with, the doctor must contemplate effective options for subsequent therapy.

Current retrospective data suggest that there is no cross-resistance between tyrosine kinase inhibitors (TKIs), which means that they can be effectively used in sequence. These data also hint to a preferred treatment sequence, where patients treated with sorafenib prior to sunitinib may experience longer periods of progression-free survival compared with those receiving sunitinib then sorafenib. Furthermore, Phase III evidence indicates that the mTOR inhibitor, everolimus, retains full efficacy in patients who have already been treated with both sorafenib and sunitinib. Therefore an optimal sequence, based on currently available evidence, might be two TKIs followed by an mTOR inhibitor.

Further to this, results from a Phase III study have shown that treatment with sunitinib achieved a median overall survival (OS) greater than two years in patients with metastatic RCC. The data support the recent publication of final guidance from the UK's National Institute for Health and Clinical Excellence (NICE), which recommends the use of sunitinib for the first-line treatment of advanced RCC.

The results, published in the online edition of the Journal of Clinical Oncology, also support a recent recommendation made by a group of oncologists in the UK to use sunitinib as a first-line treatment for metastatic RCC.

The trial data showed that the median OS for patients who received sunitinib versus interferon (IFN) alpha was 26.4 versus 21.8 months, respectively (p=0.051). However, an exploratory analysis of patients who received only one line of treatment (ie, no subsequent treatments after stopping their sunitinib or IFN alpha therapies) showed that sunitinib almost doubled the median OS compared to IFN alpha (28.1 vs 14.1 months; hazard ratio=0.647; p=0.003). This is a reflection of clinical practice in the UK where generally patients are only funded for one line of treatment at most.

According to Pfizer, before NICE guidance only one-third of primary care trusts (PCTs) were funding sunitinib to some extent. Since the guidelines were published, 90 per cent of PCTs have committed to full funding of sunitinib in accordance with NICE guidance. In 2007, Pfizer cut the price of sunitinib by 5 per cent and committed to providing one cycle/course of the treatment free of charge to every eligible patient in the UK, in an effort to increase patient access. This move amounts to an average saving of between 19 and 29 per cent per patient for the cost of treatment, depending upon the type and stage of their tumour. The average annual cost for a patient taking sunitinib is £24,168.

Matthew Dennis - Editor, Cancer Drug News

Tuesday, May 12, 2009

Cervarix on top in head-to-head, but how meaningful?

The first comparative study of the two licensed human papillomavirus (HPV) vaccines, Cervarix and Gardasil (HPV types 6, 11, 16, 18 recombinant vaccine), has shown that the former generated a significantly higher immune response as measured by neutralising antibodies (Abs) and memory B-cells.

Although GlaxoSmithKline has touted these results as highly positive, others have hit back claiming that the trial is meaningless as it did not look at which vaccine was more effective at preventing actual cases of cervical cancer or precancerous lesions. This would require a longer and larger trial, which GSK has said it has no plans to conduct. Instead, the company hopes that the head-to-head study will boost the profile of Cervarix, which is yet to be launched in the US and is trailing Sanofi Pasteur MSD's (sanofi-aventis and Merck & Co joint venture) Gardasil in global markets.

Meanwhile, recent data on Gardasil have shown that the vaccine offers protection from certain HPV strains for up to 9.5 years; previously, data only showed its effects for five years. In another study, Gardasil reduced the number of abnormal Pap tests and cervical procedures. However, with Gardasil's US sales falling and Cervarix not even on the market yet in that territory, can the comparative trial data make a difference in revenues for GSK?

Gardasil, which was first to market, and launched in the US and Europe in 2006, generated sales of US$1.4 billion in 2008, while Cervarix brought in just US$231 million. Cervarix is still awaiting US marketing approval, and has only been adopted as the vaccine in national immunisation programmes for two European countries, the UK and the Netherlands. The FDA refused to approve Cervarix until GSK provided more clinical information, but the company expects approval to come later this year.

So what of the new comparative data? The presence of Abs is a first indication of the body's ability to protect itself against disease, but this does not necessarily mean Cervarix could prevent more infections than Gardasil. The study showed that Cervarix provided significantly higher neutralising Ab levels than Gardasil: more than two-times higher for HPV type 16 and more than six-times higher for HPV 18. For both virus strains, Cervarix also induced 2.7-times more memory B-cells, another important element of the immune system.

According to GSK, the study "offers the first evidence that these two vaccines do not generate the same immune response against HPV types 16 and 18, the two most common cancer-causing virus types". Its competitor was dismissive of the data, with Bennett Lee, Medical Director for Gardasil at Sanofi Pasteur MSD commenting: "We see no clinical relevance in the results of this study ... and we don't see the point of doing such a comparison. If you want to compare vaccines, you compare clinical efficacy". However, the final word will come from doctors and patients when, and if, Cervarix is licensed in the US later this year.

Matthew Dennis - Editor, Cancer Drug News