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Biotech / Medical : Abgenix, Inc. (ABGX) -- Ignore unavailable to you. Want to Upgrade?

To: Madharry who wrote (210)	6/1/2003 5:52:36 AM
From: Icebrg	Read Replies (1) \| Respond to of 590

Harry >> Is it possible that they believe the sample patient population that they have might somehow be skewed and there fore they want to expand it by 50 to see if they end up with the same percentages? >> It is difficult to say. There are a number of reasons why a study size is increased. In most cases it is an indication that things have not gone exactly as expected and/or that the investigators want to test the drug under different conditions or on patients with different characteristics. Judging from what was reported, the drug was used to very good effect. 65 % percent of a heavily pre-treated patient population was showing signs of stable disease or better. So, judging the results, based only on that piece of information, things proceeded in a good way. There are however also negative vibrations. The companies did not release any information on what happened later on. The 65 % figure refers to the situation after 8 weeks. If most of the patients with a response relapsed shortly thereafter and saw their cancers starting to grow again, it would not be so positive. The window of opportunity provided by the mAb would be limited. Ideally, you would like to see a situation where the drug is able to balance out the growth of cancer tumors. I don't think that this class of drugs will turn out to be great killers of cancer cells on their own, but they should ideally be able to stop the cancer cell proliferation. So, the two still unanswered question this raises is: 1. Why did they report such limited data? and what happened after the 8 weeks, and 2. Why did they find it necessary to increase the size of the trial by 50 %? >>They seem to think there is a strong correlation between success and patients getting a skin rash. anyone buy into that?? >> It depends on your criteria for success. The skin rash (as I have understood this) is a sign that the amount of antibody in circulation has reached a saturation level. Certain skin cells (which are also growing and depending on growth signals through the EGF receptor) are effected which is manifested through the skin rash. This is however not in any way an indication of if enough of the antibodies are reaching the cancer cells inside the tumors or if they have the intended effect on these tumor cells. The conditions inside a tumor are not considered ideal for penetration by large molecules like mAbs. We don't know if the binding of the EGF-receptors will result in inhibition of tumor growth etc. So, the skin rash may be taken as an indication of the level of saturation of the mAb, but it is in no way indicative of the success of the cancer treatment as such. >>What is the downside here if this drug does not get approved?>> We are still very far from an approval. And it is even doubtful if the intention even was to seek approval for ABX-EGF used as a single agent. ABGX and AMGN have another study running in parallel where they are evaluating the mAb and chemotherapy agents used in combination. However, nothing was reported on that trial at the conference. The concern is that if the perception is that these trials are not going well, the stock price will tank regardless of where this specific trial fits into the development scheme. You may compare these results with what is reported for Imclone's Erbitux. The results from this mAb are perceived as something of a success even though the mAb is supposed to be less well suited for its task. It is chimeric whereas Abgenix's mAb is fully human. Chimeric mAbs are supposed to illicit negative immune responses and to have less affinity to their target antigens. The reason for the positive response to the Erbitux trials is that the mAb was investigated in another setting (different type of cancer and in a combination treatment). Abgenix mAb would most probably have been able to achieve the same or even better results if tested under similar conditions, but they are not so far yet in their development. The downside judging from other companies with similar technologies would be that the share price will fall down to cash or even below. Cash is at around 4 dollars per share. Erik