Genentech made the decision to restrict the availability of Avastin to compounding pharmacies when it became clear that they were divvying up and repackaging the drug as a cheaper alternative treatment for wet age-related macular degeneration (AMD).
Although Genentech has given pharmacies and ophthalmologists an extra month by pushing out the cut-off date from 30 November to 1 January, physicians are still non-plussed by the firm's actions, with the American Academy of Ophthalmology (AAO) saying it "is hard to overlook Genentech's initial decision."
The company announced its controversial plans earlier this month, with much speculation that the motivation for the move was purely financial, driven by the desire to force patients to use the company's much pricier AMD treatment, Lucentis (ranibizumab).
While Avastin has not been approved for the treatment of AMD, the two drugs share a similar mode of action by inhibiting vascular endothelial growth factor (VEGF).
Lucentis was designed specifically for the treatment of wet AMD, but costs thousands of dollars compared to off-label use of Avastin at a fraction of the price.
Genentech has largely pointed to the US Food and Drug Administration (FDA) when asked for an alternative explanation of the move, saying " a series of FDA actions " contributed to the firm's actions.
The company highlights the agency's concerns over sterility and repackaging of the drug for ocular use, and the fact that Genentech's manufacturing processes are not designed with ocular use of the drug in mind.
In a statement made just days after Genentech revealed its plans, however, the FDA explicitly states that "the Food and Drug Administration did not ask Genentech to stop distributing Avastin to compounding pharmacies, and FDA has not taken action to limit the off-label use of Avastin."
While the agency did note that it was worried about the " manipulation of sterile products " due to increased risk of contamination, it also pointed out that to date, the adverse reactions reported following use of Avastin for ocular indications were consistent with those of Lucentis.
The National Institute of Health is sponsoring a head-to-head trial between the two drugs starting this year.
Genentech's original timescale gave ophthalmologists and pharmacies seven weeks' notice before pharmacies would no longer be able to source their supplies of Avastin from wholesalers.
This has now been extended by a month following a meeting between the AAO, the American Society of Retina Specialists (ASRS) and Genentech's CEO, president and chief medical officer.
Along with the stay of execution, Genentech also agreed to overturn its decision if the company gets sufficient clearance to do so from the FDA.
In the meantime, however, the various bodies representing those treating sight-threatening disorders have been vociferously opposing the company's decision.
"Senior executives at Genentech have been contacted repeatedly by ASRS leadership in order to strenuously protest the Avastin decision, [and] strongly advise the company of the absolute opposition of our membership to any limitation of our patients' access to this widely used drug," said a statement released earlier this month by the ASRS.
Over the third quarter Avastin generated $597m in sales, with Lucentis coming in at $198m, obviously impacted by the off-label Avastin use.
The company insists that it was not motivated by money in any way in making the decision to restrict Avastin availability: "We understood that some would disagree with our decision to stop supplying Avastin to compounding pharmacies and would accuse Genentech of making profit, not patients, its priority," the company said in an open letter earlier this week.
"Genentech's decision was not motivated by a desire for increased profits."
It is likely however, that physicians will find alternative ways of acquiring Avastin for ocular use, even after the Genentech deadline has passed.
Compounding pharmacies advised the ASRS that even with the original November date, many had supplies of Avastin in stock that should satisfy demand through until well into the spring or summer, giving prescribers a little time to establish their new supply routes.