Genentechs decision to limit the availability of Avastin (bevacizumab), a cancer drug used off-label to treat patients with age-related macular degeneration (AMD), is now being questioned by the U.S. Senate.

In a letter to Susan Desmond-Hellman, M.D., M.P.H., Genentechs president, product develop- ment, Sen. Herb Kohl (D-Wis), chairman of the Special Committee on Aging, said that he has authorized the committee staff to make inquiries about the circumstances behind Genentechs decision.

Genentech announced that, as of January 1, 2008, it will no longer allow compounding pharmacies to purchase Avastin directly from wholesalers. In an open letter to the retinal community, Dr. Desmond-Hellmann said that several events led to the decision, including the approval of its drug specifically designed to treat AMD, Lucentis (ranibizumab), in addition to concerns raised by the FDA about the sterility and repackaging of Avastin for ocular use.

Another issue, however, is cost. A single injection of Lucentis costs about $2,000, while an injection of Avastin costs less than $100.

The decision to curb Avastin could cost taxpayers $1 billion to $3 billion a year, a Wall Street Journal article says. Any instance that could cost taxpayers potentially $1 to $3 billion is of great concern to me, Sen. Kohl wrote.

Sen. Kohl has asked Genentech to provide the committee with documentation concerning the decision to limit the availability of Avastin. The company has until December 7 (after Review of Optometrys press time) to respond.

We are aware of the letter and do plan to cooperate with it, and are working with his staff now to determine what information they need from us, says Krysta Pellegrino, spokesperson for Genentech.

In unrelated news, intravitreal injections of Lucentis and Avastin cause transient rises in intraocular pressure, reported researchers at Novembers American Academy of Ophthalmology meeting.1 In one study, 55 intravitreal injections of Lucentis were administered to patients with exudative AMD. IOP went from an average of 13mm Hg before injection to 38mm Hg one minute after injection, and then decreased to 18mm Hg at 30 minutes. IOP returned to normal at the subsequent visit.

Ronald Frenkel, M.D., one of the authors of the aforementioned study, acknowledged that there was no evidence of adverse effects on the optic nerves, but he and his colleagues concluded that these IOP spikes potentially could be damagingespecially in patients with advanced glaucoma.

Meanwhile, in a prospective case series of 51 consecutive patients who received 2.5mm injections of Avastin, IOP rose to 53.7mm Hg immediately after a 2.5mm injection, and then dropped to 20.8mm Hg in 30 minutes. IOP was normalized at 24 hours.2

Says Ms. Pellegrino, Intraocular pressure [increase] is an adverse event thats often associated with any intraocular injection.

1. Frenkel RE, Lakshmi M, Frenkel MP. Are recurrent transient rises in IOP a concern for patients following intravitreal injections or ranibizumab (Lucentis)? Poster No. 320. American Academy of Ophthalmology, New Orleans, 2007.
2. Evans TJ, Wu L. Short-term changes in IOP after an intravitreal injection of 2.5mg of bevacizumab. Poster No. 324. American Academy of Ophthalmology, New Orleans, 2007.