Tuesday, September 16, 2008

Bidding war to start for ImClone?

ImClone Systems' Chairman of the Board, Carl Icahn, has stated that the Special Committee of ImClone's Board of Directors has informed Bristol-Myers Squibb that following the Special Committee's review and discussion, and based upon the advice it received from its advisors, the Special Committee has determined that the unsolicited offer that ImClone received from BMS to acquire ImClone for US$60 per share in cash is inadequate.

Icahn also disclosed that he has had several conversations with the Chief Executive Officer of a large pharmaceutical company. As a result of such conversations, the pharmaceutical company has submitted a proposal, subject to due diligence, but not subject to financing, to acquire ImClone for US$70 per share in cash. Names being bandied about for the unknown bidder include Merck KGaA, Pfizer and GlaxoSmithKline, as well as AstraZeneca and sanofi-aventis. The Special Committee has determined, subject to the execution of a confidentiality agreement, to allow this company to conduct due diligence for a two-week period, subject to extension by mutual consent. No determination has been made as to whether US$70 per share would be adequate.

In response to this disclosure, BMS sent a letter to Icahn stating its disappointment that the offer had been rejected without discussing its merits with BMS and its advisors. BMS also noted that, in contrast to the competing offer, it has made a formal written offer that has been approved by its Board of Directors, is not subject to due diligence and has been fully disclosed to ImClone's stockholders.

BMS currently holds the exclusive long-term marketing rights in the US to Erbitux (cetuximab) and related compounds, including IMC-11F8. BMS stated that it has no intention of agreeing to any modifications to these rights. Additionally, ImClone should understand that BMS’ offer is for the entire company, and any potential restructuring of ImClone could severely jeopardise its value and deprive stockholders of the benefits of the BMS offer.

BMS continues to look forward to engaging directly with ImClone and its financial and legal advisors to discuss the merits of its all-cash offer to acquire the approximately 83 per cent of the company that BMS does not already own. In reply, ImClone submitted a letter to BMS in which it stated that with regard to the assertion concerning rights to IMC-11F8 (which, if ultimately approved for sale, may have a significant competitive effect on Erbitux), ImClone disagrees that BMS' rights are clear and does not waive any rights that ImClone may have with regard thereto. If BMS wishes to make another offer that it believes ImClone would not find inadequate, it is free to do so. Upon receipt of that offer, ImClone will respond appropriately. However, BMS' Chief Financial Officer Jean-Marc Huet has stated that the company is willing to "walk away" from the deal if needed.

Exactly what belongs to whom in the BMS-ImClone partnership will be a key question of interest as ImClone's new mystery bidder conducts its due diligence over the next few weeks. It seems likely that Merck KGaA may be the interested party because it partners with ImClone in selling Erbitux in some countries outside North America and has touted the drug's prospects of being approved for other types of cancer. Perhaps the bidding will now start in earnest?

Matthew Dennis - Editor, Cancer Drug News

Telomerase finally gives up its structure

In a landmark study, researchers from the Wistar Institute have deciphered the structure of the active region of telomerase, an enzyme that plays a major role in the development of nearly all cancers. It is hoped that this achievement will open the door to the creation of new, broadly-effective cancer drugs, as well as anti-ageing therapies. The results of the work have been published in the 31st August online edition of Nature (10.1038/nature07283).

Scientists have been searching for over ten years to develop drugs that shut down telomerase, which is considered the best target for the development of new cancer treatments, but they have been hampered in large part by a lack of knowledge of the enzyme's structure. The new findings should help investigators in their efforts to design effective telomerase inhibitors. According to lead study author, Dr Emmanuel Skordalakes, assistant professor in Wistar's Gene Expression and Regulation Program: "Telomerase is an ideal target for chemotherapy because it is active in almost all human tumours, but inactive in most normal cells. That means a drug that deactivates telomerase would likely work against all cancers, with few side effects."

In humans, telomerase adds multiple repeats of a short DNA sequence to the ends of chromosomes, known as telomeres, thus preventing damage and the loss of genetic information during cell division. When telomerase is dormant, telomeres shorten each time a cell divides, eventually leading to genetic instability and cell death. The enzyme is active in cells that multiply frequently, such as embryonic stem cells, but is switched off almost entirely in normal adult cells. Cancer cells, however, often regain the ability to activate telomerase, which has been implicated in 90 per cent of human tumours. The enzyme permits cells to replicate indefinitely and achieve the cellular immortality that is the hallmark of cancer.

Telomerase is a complex structure made up of multiple protein domains and a stretch of RNA, which contains the template the enzyme uses to synthesise telomeres. In 2007, the researchers solved the structure of a key segment of the molecule, the TRBD domain, where RNA binding occurs. However, the complexity of telomerase has proved a roadblock to determining the enzyme's overall architecture, as has the ability to obtain sufficient quantities of the enzyme.

By screening a wide variety of organisms, including protozoa and insects, the scientists discovered that a gene from the red flour beetle could produce telomerase in copious amounts, and a stable form. The researchers used X-ray crystallography, to determine the 3D structure of the enzyme's active region, the catalytic component called telomerase reverse transcriptase protein (TERT). The work revealed surprising features, including the fact that the molecule's three domains are organised into a doughnut shape, an unexpected configuration. Knowledge of the structure allowed the researchers to create a model of the enzyme's function. Looking forward, the scientists plan to further study TERT and search for new telomerase inhibitors that could become cancer therapies, as well as looking at modifying existing drugs. Now telomerase has finally given up its structure, the hard work really starts.

Matthew Dennis - Editor, Cancer Drug News

Price may prohibit HPV vaccination in developing world

As vaccinations against human papillomavirus (HPV) begin for girls in another western country, this time in Scotland, questions remain about how best to utilise this technology in other world regions. As discussed at the World Cancer Congress, which was held from 27th to 31st August, in Geneva, Switzerland, the development of highly-effective vaccines against HPV and promising new screening tests provide an unprecedented opportunity to tackle the disease in poor countries, where pap smear screening has largely failed because it is too expensive and too complicated to implement.

At present, approximately 80 per cent of cervical cancer (CC) deaths occur in developing countries, and estimates predict that if current trends continue, these regions will face a 75 per cent increase in the number of cases in the next two decades. Presented at the Congress was the first broad analysis of the cost-effectiveness of introducing HPV vaccination and new screening methods into the hardest hit regions of the world, which include Asia-Pacific, Latin America and the Caribbean. The benefits varied, depending on the size and make-up of the population and the burden of CC in each country.

It was determined that in the Asia-Pacific region, which accounts for more than half of the world's CC cases, vaccination would be cost-effective, even in the poorest countries, if the cost per vaccinated girl was between US$10 and US$25. For Latin America and the Caribbean, the cost per vaccinated girl, including delivery and logistics costs, would have to be less than US$25 to be cost-effective for all countries. In the most developed populations in the region, vaccination would be cost-saving if the cost per vaccinated girl is between US$25 and US$60, and cost-effective at higher prices.

According to Professor Francesc Xavier Bosch of the Catalan Institute of Oncology: "Efforts are needed now to adapt the current price of the vaccines so they meet what individual countries can afford; the solution may be tiered pricing according to gross national income per capita and according to the scale of country effort. Currently the vaccine's price in the private sector is approximately US$120 per dose, or US$360 per vaccinated girl. Many countries will need subsidies for some time."

The price of the vaccine and the support for massive vaccination campaigns is one of the biggest barriers for the moment, but several other challenges lay ahead. Those include generating the political support for an intervention whose pay-off is two or more decades away, cultural acceptability of the vaccine and monitoring the circulating virus. Uncertainties that may affect the success of vaccination programmes include the duration of protection and whether booster shots might be needed, and whether the vaccines will be as effective in girls whose immune systems are suppressed by either malnutrition or other chronic infections, such as HIV or malaria.

For the near future, in developing countries, both vaccination and screening will be needed. However, in the beginning, many countries may have to continue to focus on screening alone until the vaccine becomes more affordable.

Matthew Dennis - Editor, Cancer Drug News