(Adds analyst comments, details, byline, updates shares)
By Lewis Krauskopf
NEW YORK, April 9 Pfizer Inc (PFE.N) and Nektar
Therapeutics (NKTR.O) said on Wednesday clinical trials of the
inhaled insulin Exubera found increased cases of lung cancer,
leading Nektar to stop seeking a marketing partner for the
troubled product and abandon it.
Nektar shares tumbled 25 percent, while shares of MannKind
Corp (MNKD.O), which has been developing its own inhaled
insulin, plummeted 58 percent. Pfizer was down slightly at
The lung-cancer revelation dealt a final setback to
Exubera, which held the promise of letting diabetics avoid
needle sticks and was once projected by Pfizer to be a $2
billion-a-year blockbuster. Instead, Exubera has been a
commercial flop that has sullied the inhaled insulin field.
Over the course of the clinical trials, Pfizer said six of
the 4,740 Exubera-treated patients versus one of the 4,292
patients not treated with Exubera developed lung cancer. One
lung cancer case was also found after Exubera reached the
Pfizer said on Wednesday it updated the product's labeling
to include a warning with safety information about lung cancer
cases found in patients who used Exubera, which U.S. regulators
approved in January 2006.
The warning states all patients who developed lung cancer
had a history of cigarette smoking, and that too few cases
existed to determine whether the development of lung cancer is
related to Exubera use.
Despite high hopes for Exubera, it garnered few
prescriptions. The medicine was dogged by concerns about lung
safety and about the inconvenience of the bulky device used to
administer the product.
Pfizer said in October it would stop marketing Exubera and
returned rights to Nektar. Pfizer reported $12 million in
Exubera sales through the first three quarters of 2007; in
October it took a pretax charge of $2.8 billion related to
Since then, Exubera has not been actively marketed but
existing patients were able to get prescriptions while
transitioning to an alternative therapy.
The warning in the label stemmed from an ongoing review of
data from the Exubera clinical trial program and post-marketing
experience by Pfizer and the U.S. Food and Drug Administration,
Pfizer said it will be discussing withdrawals of marketing
authorizations for Exubera with regulatory agencies.
Nektar said it will cease all spending associated with its
inhaled insulin programs, including a next-generation version
in early clinical testing, and will not incur charges related
to the event.
"The news of an increased number of lung cancer cases is
disappointing given that as recent as the year-end quarterly
conference call, management reiterated the high level of
interest from potential partners," Pacific Growth Equities
analyst Patricia Bank said in a research note.
Bank downgraded her rating on Nektar stock to "Neutral"
from "Buy" on the news.
Nektar Chief Executive Howard Robin said in a statement the
company has moved away from inhaled insulin the past year. Its
experimental pipeline includes a treatment for pneumonia in the
lung about to enter late-stage development, and mid-stage
projects for colorectal cancer and opioid-induced
Since Pfizer's exit last year, Eli Lilly (LLY.N) and Novo
Nordisk (NOVOb.CO) also ended inhaled insulin development
MannKind has been steadfast in its commitment to its
experimental inhaled insulin, Technosphere Insulin, saying it
held advantages over the other products.
But Natixis Bleichroeder analyst Jon LeCroy downgraded his
rating on MannKind stock to "Sell" from "Hold" on the Exubera
"We view this as an absolute disaster for MannKind and do
not see a believable scenario in which the FDA would approve
another inhaled insulin," LeCroy said in his downgrade note.
MannKind shares were off $3.39 at $2.46 in morning trading
on the Nasdaq to a multiyear low. Nektar shares fell $1.79 to
(Reporting by Lewis Krauskopf; Editing by Brian Moss and