Replies to post #1070 on Biotech Values

[DewDiligence]

Re: Allergan’s Tazarotene:

>> Sorry about not giving details about Tazarotene, but I ignored it because it is for me the same thing than Accutane… <<

Similar, yes, but not the same thing.

Dr. Patricia Walker (Allergan VP of Dermatology) explains the key differences between Tazarotene and other retinoids in Allergan’s R&D Day presentation (go to 1 hour, 51 minutes into the webcast). Tazarotene binds to the RAR retinoid receptors (alpha, beta, and gamma), but has no affinity for the RXR retinoid receptors, as Accutane does.

In short, Tazarotene is a distinct drug that must be considered on its own merits apart from any other members of the retinoid family. Regards, Dew

[DewDiligence]

More research on retinoid drugs in AMD:

This abstract is about isotretinoin (a.k.a. Accutane, a.k.a. 13-cis RA), and the author is our old friend Eugene de Juan, CEO of the closely-held InnoRx, the company SRDX recently invested in [#msg-2200452]:

http://www.kenes.com/isopt/inv_abstracts/De_Juan2.doc

>>
Purpose: Determine whether evidence for efficacy exists for oral 13-cis retinoic acid (RA) to stabilize visual acuity in AMD patients with subfoveal occult CNV.

Methods: We performed a prospective pilot trial using oral 13-cis RA as a treatment for subfoveal occult CNV in AMD patients. Patients were instructed to take 40 mg. of 13-cis RA (tablet) twice daily for five months, stop treatment for two months and then resume treatment for five additional months. Patients were followed monthly with ETDRS visual acuity (VA), anterior and posterior segment examinations, fluorescein angiography.

Results: Eleven patients, age ranging from 64 to 88-years (median 73-years) were enrolled. VA ranged from 20/40 to 20/400. Follow-up ranged from five to 16 months (median12 months). Initial visual acuity (VA) ranged from 20/40 to 20/400 (median 20/64). Median VAs were 20/80 at three, 20/100 at six and 20/160 at 12 months. VA was within +/- 2 lines of initial VA in 82% at three, 50% at six, 33% at nine and 67% of patients at 12 months. VA improved two or more lines in 45% at three, 25% at six, 50% at nine and 33% at 12 months. [Note that the FDA’s definition of improved visual acuity is a gain of at least *three* lines relative to baseline.]

Conclusions: Oral 13-cis RA may play a role in stabilizing or improving visual acuity in patients with occult subfoveal CNV in AMD patients.
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[DewDiligence]

Two more PR’s on oral Tazarotene in psoriasis, which make the case that Tazarotene is considerably safer than other retinoid drugs for chronic use:

http://biz.yahoo.com/prnews/040207/nysa004_1.html

http://biz.yahoo.com/prnews/040207/nysa001a_1.html

These studies in psoriasis will presumably bolster the safety data to support an FDA application to use oral Tazarotene in AMD (as previously discussed on this board).