Tuesday, October 21, 2008

GVAX: development halted

Cell Genesys has decided to terminate the Phase III VITAL-1 (Vaccine ImmunoTherapy with Allogeneic Prostate Cancer Cell Lines) trial of GVAX immunotherapy in patients with asymptomatic, metastatic hormone-refractory prostate cancer (HRPCA) following an independent Data Monitoring Committee (IDMC) analysis, which indicated that the trial had a <30 per cent chance of meeting its predefined primary endpoint of an improvement in survival. In August, the company halted VITAL-2, the second Phase III trial investigating GVAX in PCA, after a recommendation from the IDMC following the observation of an imbalance in deaths between the two treatment arms.

Following the termination of VITAL-2, Cell Genesys requested the IDMC conduct a futility analysis of the VITAL-1 trial, which was fully enrolled in 2007 with 626 patients and compared GVAX to Taxotere (docetaxel) plus prednisone. The latest news hit the company's stock price hard, with shares falling by 73 per cent from a close of US$0.61 on 15th October to open at US$0.16 on 16th October.

In view of these terminations, Cell Genesys is to place on hold the further development of GVAX for PCA pending a review of the programme with its collaborator, Takeda Pharmaceutical. As a result, Cell Genesys will reduce its staff of 290 by approximately 75 per cent by the end of 2008, with further reductions anticipated in the first half of 2009 as additional activities are phased out. As of 30th September, the company had approximately US$150 million in cash and currently estimates that the year-end cash will be approximately US$128 million. Personnel-related restructuring charges of approximately US$12.8 million are expected to be incurred in the fourth quarter of 2008.

Cell Genesys has also reported results of a preliminary analysis of the VITAL-2 trial. In contrast to VITAL-1, the VITAL-2 study was conducted in patients with symptomatic, metastatic HRPCA and compared the combination of GVAX+docetaxel to docetaxel+prednisone as a control. At the time that this study was terminated, the IDMC reported an imbalance in deaths between the two treatment arms that was observed during a routine safety monitoring meeting of the committee. More specifically, of 114 deaths at the time of the IDMC review, 67 occurred in the GVAX+docetaxel treatment arm and 47 in the docetaxel+prednisone control arm.

A total of 408 patients had been enrolled in the study up to that point in time. The company has now conducted an initial analysis of the incomplete trial data set that was reviewed by the IDMC in August. The analysis has revealed no apparent imbalance in patient baseline characteristics with respect to both demographic and disease prognostic factors. In addition, no significant toxicities in the GVAX+docetaxel therapy arm were observed that could explain the imbalance in deaths and in fact, the vast majority of deaths in both treatment arms were reported as due to progression of PCA. Of note, fewer treatment cycles with docetaxel were administered to patients in the GVAX+docetaxel arm compared to the control arm, a difference which was statistically significant.

In a conference call, the company's Chief Executive Officer, Stephen Sherwin, stated that Cell Genesys has since found no evidence that the GVAX regimen carried toxic effects that could explain the additional deaths. "We don't have all the answers," he commented, although cancer sufferers, shareholders and employees will wish that he at least had some.

Matthew Dennis - Editor, Cancer Drug News

Tuesday, October 14, 2008

NICE set to block Tyverb's use on NHS

A draft recommendation by the UK's National Institute for Health and Clinical Excellence (NICE) in a second technology appraisal consultation document (ACD) has indicated that GlaxoSmithKline's Tyverb (lapatinib; known as Tykerb in the US and certain other markets) should not be used in the NHS, except in clinical trials. The oral drug is currently approved in the EU in combination with Xeloda (capecitabine) for the treatment of women with ErbB2 (HER2)-positive advanced breast cancer (BC), whose disease has stopped responding to Herceptin (trastuzumab). The draft guidance comes despite GSK proposing a patient access programme (PAP), where it would bear the cost of the drug for the first 12 weeks of treatment.

Lapatinib, in combination with capecitabine, is the only treatment option that is licensed for use in patients with this aggressive form of advanced BC, who have limited treatment options remaining if their cancer has continued to grow despite treatment with standard chemotherapies and trastuzumab for advanced disease. In a pivotal trial that led to its EU licence, lapatinib+capecitabine significantly increased the time-to-progression (TTP) for patients with ErbB2-positive BC compared with capecitabine alone. In its draft guidance, NICE acknowledged that lapatinib is a clinically-effective option and noted that lapatinib+capecitabine was associated with improved TTP and progression-free survival.

In recognition that the first ACD from NICE did not consider lapatinib to be cost effective in treating this patient population, GSK proposed a PAP, where the company would bear the cost of lapatinib for all eligible patients, for up to the first 12 weeks of treatment. The NHS would commence payment only for those patients who continue to receive clinical benefit beyond 12 weeks. Criteria for continuation of therapy beyond 12 weeks would be determined by the individual person's clinician, based on reduction in lesion size, presence of stable disease or improvement in other response criteria such as symptoms. This programme was designed to provide access to all eligible patients and deliver cost-effectiveness at a threshold that should have been acceptable to NICE.

The cost effectiveness of lapatinib+capecitabine was supported by a comparison to trastuzumab-containing regimens and capecitabine alone, representing the established treatment regimens in NHS clinical practice. Whilst NICE accepted that trastuzumab is widely used following progression of the disease, the Committee suggested that it was unlikely to be cost effective, and therefore did not accept trastuzumab as a valid comparator. According to GSK, the way in which the decision was made makes it very difficult to ever demonstrate the cost effectiveness of lapatinib in this patient population, even in light of the proposed PAP.

Following the ACD, GSK will continue to work with NICE to demonstrate the cost effectiveness of lapatinib in all eligible patients by seeking to validate trastuzumab as a legitimate comparator. The next meeting will be held on 19th November, however, it looks as though NICE will stick with its current draft guidance and recommend against funding lapatinib on the NHS.

Matthew Dennis - Editor, Cancer Drug News

Market jitters affecting takeovers?

As the world financial crisis deepens, the potential takeover deals involving Genentech and Roche, as well as ImClone Systems and Bristol-Myers Squibb, continue to play out. The current market situation could have an impact on the first takeover, although the second looks more likely to proceed smoothly.

For the first time since Roche made its bid to acquire Genentech in July for US$89.00 per share, the latter's shares have dropped below the offer price, ending on 29th September at US$85.30. The uncertainty now surrounding the bid has fuelled speculation that an improved offer may not be made. When Roche proposed the deal, the cost of borrowing was not as high as it in the current climate. Now there are concerns that Roche would have trouble financing the deal, which currently stands at US$43.7 billion, given the current credit market conditions. However, many analysts believe Roche's strong balance sheet and predictable cash flow will still allow it to secure funding for the deal.

The current situation could ultimately work in Roche's favour as the company may choose to draw out the process in order to extract the lowest possible price for Genentech's remaining shares. It may be that many Genentech shareholders would also prefer to wait, given that interim results are expected in November from a key clinical trial looking at the use of Avastin (bevacizumab) in colon cancer patients who have had tumours surgically removed; final results of the 2,700-patient study are due in 2009.

As for BMS' takeover offer for ImClone, which currently stands at US$62.00 per share in cash, Carl Icahn, ImClone's Chairman of the Board, recently commented that the "hostile tender of US$62, at this time, seems absurd". ImClone reportedly has an offer from another large pharmaceutical company of US$70.00 per share, also in cash, subject to due diligence, which was scheduled to be finished on 28th September. ImClone is expecting that a solid offer from this company will be made or a formal rejection, in which case the suitor will be identified, by the end of business on 1st October. Both of these offers, BMS' valued at US$4.7 billion and the other at US$6.1 billion, do not rely on either company raising funds so should not be affected by recent financial developments.

But to add to the uncertainty, Merck KGaA has entered the fray. Although the company has said that it will not bid for ImClone on its own, it has stated that it may consider taking part in a potential approach for the company. Could it join forces with rumoured suitors, such as Eli Lilly and Pfizer, which has coincidentally said recently that it will focus its early-stage research and development programmes on high growth areas, including cancer?

Matthew Dennis - Editor, Cancer Drug News