Inhalable Drugs on the Launch Pad: Will They Take Off?

Companies continue to develop inhaled insulin and other drugs, despite the problems that Pfizer's "Exubera" experienced.
Apr 02, 2008
Volume 32, Issue 4

Pharmaceutical companies that face dwindling new-drug pipelines are pursuing new delivery methods for their drug products. One strategy is to develop respiratory delivery techniques for drugs that are now administered by injection. Pfizer's (New York) "Exubera" product and Novo Nordisk's (Bagsvaerd, Denmark) "AERx" treatment were high-profile examples of this gambit. Although these companies stopped supporting their new drugs after they failed to meet market expectations, researchers and manufacturers still consider respiratory delivery of biologicals a viable option.

The rise of Exubera

When Pfizer and its development partner Nektar Therapeutics (San Carlos, CA) introduced the Exubera inhaled-insulin product in summer 2006, respiratory drug delivery enjoyed a moment in the spotlight. No company had manufactured an inhaled insulin before, and Exubera was projected as a potential blockbuster.

John Patton, chief scientific officer and cofounder of Nektar, says that Exubera is a friendly option for patients who otherwise would postpone taking injected insulin for years. Exubera thus can reduce premature death and the early advancement of diabetes sequelae that patients would otherwise suffer, according to Patton. Patients also appreciate the fact that Exubera is the first room-temperature stable insulin formulation.

Fluorescence-dye solution (above) and microscopy imaging (left) of fluorescence-labeled pulmonary "CaP" insulin parti-cles from BioSante. (PHOTOS COURTESY OF BIOSANTE PHARMACEUTICALS)
The product has therapeutic benefits as well. "Exubera's onset is just as fast as that of monomeric insulin, yet it has a longer release profile and lasts longer," according to Patton. He notes that Exubera patients' postprandial and fasting-plasma glucose levels were lower and closer to normal than those of patients who injected insulin.

Robert E. Sievers, professor of chemistry at the University of Colorado and CEO of Aktiv-Dry (Boulder, CO), says Exubera was "a scientific tour de force." He adds that the inhaler that delivered the drug was "a wonderful mechanical apparatus." Aktiv-Dry uses Exubera as a standard against which to measure its own respiratory drug-delivery devices. "That speaks a lot for it," Sievers observes. "It says that Exubera works, both the powder and the inhaler."

Exubera falls

Despite Pfizer's best efforts, Exubera's sales were disappointing, and in Oct. 2007, Pfizer decided to stop investing in Exubera. In a company press release, Jeff Kindler, Pfizer's chairman and CEO, said that Exubera had "failed to gain the acceptance of patients and physicians."

What went wrong? Richard Dalby, professor of pharmaceutical sciences at the University of Maryland, notes that Exubera's device is 16 cm tall, while pressurized metered-dose inhalers are generally 9 cm tall. Exubera's size might have been off-putting to patients and healthcare workers more familiar with syringes and injection pens.

"A larger problem was the realization that most patients would require concomitant administration of a long-acting insulin, which was only available by injection," Dalby observes. "In effect, Exubera added to the complexity of a diabetic's drug regimen rather than simplifying it or making it less painful."

Stephen M. Simes, president and CEO of specialty drug company BioSante Pharmaceuticals (Lincolnshire, IL) makes a similar point, noting that Exubera was impractical because it required an "almost one-for-one replacement of injection with inhalation."

A model demonstrates the use of Aktiv-Drys "PuffHaler" inhalation device. (PHOTO COURTESY OF AKTIV-DRY)
"Doctors didn't think it brought the patient that much additional advantage," Sievers says. Physicians decided it would be easier to continue therapeutic regimens that were familiar to patients, rather than encourage something that was new and, in their view, unnecessary.

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