NEW YORK (

TheStreet

) -- Shares of

MannKind

(MNKD) - Get Report

plummeted in after-hours action on Wednesday after the

Food and Drug Administration

delayed a decision on the regulatory status of its Afrezza treatment for diabetes.

Valencia, Calif.-based MannKind said it's

received a complete response letter

from the FDA regarding Afrezza, a quick-acting form of insulin that's

meant to be inhaled.

.

The letter means the FDA has additional questions about Afrezza's new drug application. As a result, the agency has requested two additional clinical trials -- one for patients with type 1 diabetes and one for patients with type 2 diabetes -- be conducted using the latest version of the company's MedTone inhaler.

While we are disappointed with the complete response letter, we are encouraged that the FDA is asking for clinical studies only to confirm the bridging and handling of the next-generation device in order to compare it to the device used in our extensive clinical program," said Alfred Mann, the company's chairman and CEO, in a statement. "We remain committed to working with the FDA to make AFREZZA available to people with diabetes."

The stock was last quoted at $5.16, down 43.4%, on volume of 2.6 million, according to

Nasdaq.com

. The shares had already fallen more than 7% to $9.11 in the regular session with volume running more than twice its trailing three-month daily average of 3 million. The stock sank as low as $4 in extended trades, well below its 52-week low of $4.76 from late May 2010.

eBay

Online auctioneer

eBay

(EBAY) - Get Report

was a bright spot in late trades after it

topped Wall Street's expectations

for its quarterly results after the closing bell.

The shares advanced 3.1% to $30 on volume of 3.3 million in extended trades as eBay said it earned $683.8 million, or 52 cents a share, for the three months ended Dec. 31 on a non-GAAP

generally accepted accounting principles basis. Revenue increased 5% on a year-over-year basis to $2.5 billion.

The performance, which eBay attributed to "solid productivity, strong growth, and a lower tax rate," was ahead of the average estimate of analysts polled by

Thomson Reuters

for a profit of 47 cents a share in the December period.

eBay also forecast non-GAAP earnings of 44 to 46 cents a share for its fiscal first quarter and $1.90 to $1.95 a share for the full year. Wall Street's current consensus estimates are for profits of 45 cents and $1.85 a share in the respective periods.

eBay's stock has appreciated almost 27% in the past 52 weeks, although it's pulled back since hitting a 52-week high of $31.64 at the end of November. Of the 32 analysts covering the shares, the majority -- 18 -- had hold ratings in place ahead of the report.

Dillard's

Shares of

Dillard's

(DDS) - Get Report

tacked on more than 9% to $40.97 on volume of more than 40,000 after the Little Rock, Ark.-based department store retailer said in a regulatory filing that it plans to form a real estate investment trust.

In a Form 8-K filing with the

Securities and Exchange Commission

, Dillard's said it intends to set up a separate unit to operate as a REIT as it "believes the formation of a REIT may enhance its ability to access debt or preferred stock and thereby enhance its liquidity."

Dillard's, which also expects to form a captive insurance unit, said it plans to transfer its interests in certain properties to the REIT and then the parent company will lease the properties back from the REIT under "triple net" leases.

The stock has more than doubled in the past 52 weeks and hit a new 52-week high of $40.22 last week.

F5 Networks

Shares of

F5 Networks

(FFIV) - Get Report

plunged in late trades

after the Seattle-based networking products developer came in just shy of Wall Street's revenue expectations for its fiscal first quarter and offered up a mostly in-line outlook for the current period.

The stock was last quoted at $108, down 22%, on volume of roughly 4.3 million, according to

Nasdaq.com

. The volatile shares had already pulled back almost 5% since hitting a 52-week high of $145.76 on Jan. 13. The news was weighing on shares of F5 Networks' smaller competitors in late trades, including

Blue Coat Systems

(BCSI)

,

Aruba Networks

(ARUN)

,

Acme Packet

(APKT)

,

Riverbed Technology

(RVBD)

, and

Juniper Networks

(JNPR) - Get Report

.

After Wednesday's closing bell, F5 Networks reported adjusted earnings of $72.2 million, or 88 cents a share, up from a year-ago equivalent profit of $41.4 million, or 52 cents a share, and ahead of the average estimate of analysts polled by

Thomson Reuters

for earnings of 83 cents a share.

On the top line, however, the company, whose products include applications to accelerate the loading of Web pages and manage remote access to virtual private networks, fell short with revenue of $268.9 million for its fiscal first quarter ended Dec. 31. That figure missed Wall Street's consensus view of $270.6 million.

Seagate Technology

Shares of

Seagate Technology

(STX) - Get Report

slid 5.5% to $13.35 on volume of around 550,000 after the hard drive maker posted an in-line profit for its fiscal second quarter.

The company reported adjusted earnings of $159 million, or 33 cents a share, on revenue of $2.72 billion for the three months ended Dec. 31, down from a year-ago equivalent profit of $339 million, or 70 cents a share, on revenue of $3.01 billion.

The profit matched Wall Street's consensus view while revenue was slightly below the average analysts' estimate of $2.73 billion.

--

Written by Michael Baron in New York.

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Michael Baron

.

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