Biotech Values

[mcbio]

Re: VRUS (R7128 pre-clinical kidney tox)

Good responses dewo and genisi.

The first was a 6-month safety study in monkeys at doses of 200 to 2000 mg/kg/day, in July 2007, which was stopped after 13 weeks, as there were clear signs of clinical toxicity across all dose cohorts and an NOAEL was not established. A second monkey tox study started in April 2008 with a lower dose range - 10, 40, 100, and 600 mg/kg/day. No outward clinical effects were observed and if memory serves, VRUS thought the NOAEL in monkeys is well under 600 mg/kg/day.

Like dewo, I'm a little confused by the comment of NOAEL in monkeys well under 600 mg/kg/day if there were clear signs of clinical tox across all dose cohorts in the first monkey study, which included doses as low as 200 mg/kg/day. Do you just mean that the tox concerns were only seen in those doses above 600 mg/kg/day in the first study? And do you know the duration of the second monkey study, wherein VRUS observed no clinical effects?

Also, the Phase 2b is using 500 mg bid and 1000 mg bid. First, is 500 mg and 1000 mg the total dose of the drug/day or do you have to double that because it is bid (i.e., are the 500 and 1000 numbers the sum of the bid dosing)? Second, since tox was seen after 13 weeks in the first monkey study at doses both below and above what is being used in the Phase 2b and the interim safety look is at 12 weeks, if R7128 passes this initial safety look, that should be fairly reassuring.

How good of an investment do you all view VRUS if R7128 passes this initial safety look, assuming the stock is still roughly around its $300 million market cap?