Investors in Teva Pharmaceutical Industries Ltd.'s (TEVA) - Get Report  can't get a break and according to Wall Street analysts, the company isn't likely to see a reprieve anytime soon despite efforts from the company to downplay the affects. 

Shares of the Israeli pharma company closed down 14.56%, or $2.74 per share, to $16.08 on Wednesday after Mylan NV  (MYL) - Get Report said the Food and Drug Administration had approved a generic version of Teva's top-selling multiple sclerosis drug, Copaxone.

"We note, the ongoing challenges to its generics business and that with FDA approval of Mylan's generic of Copaxone, earnings/cash flow are likely to [be] affected" with the announcement, wrote David Steinberg of Jefferies in a morning note.

"TEVA managed to stay in front of generic Copaxone competition and extended its best-selling brand by 3+ years," he said, adding that that while Copaxone "has been a strong contributor to cash flow over the last two decades, growing generic competition to this franchise has been an overhang on TEVA shares in recent years."

Still, Teva remained positive, releasing a statement just before U.S. market open Wednesday, explaining that it would launch a series a appeals refuting Mylan's patents, among other things.

Teva said it would appeal the December 2016 inter partes review decisions of the Patent Trial Appeal Board that found all of the claims of three Copaxone patents to be unpatentable and also the January 2017 decision of the U.S. District Court for the District of Delaware, which declared certain claims of four Copaxone patents invalid. The two appeals "have been fully briefed and await the scheduling of oral arguments" and will be heard by a single panel of judges of the U.S. Court of Appeals for the Federal Circuit, Teva said.

In addition, Teva said it has also brought suit against five Abbreviated New Drug Application filers, including Mylan, for infringement of a patent covering a manufacturing process for glatiramer acetate product.

Despite the vow to fight some of the encroachment by others, the ultimate overhang for Teva remains its $35 billion debt pile, that the company is looking to address via asset sales.

Teva agreed to sell a portfolio of more than 20 products in the areas of contraception, fertility, menopause and osteoporosis to CVC Capital Partners Group for $703 million in cash. The products are marketed and sold outside the U.S.

In the other transaction, Teva is selling Plan B One-Step, Take Action, Aftera and Next Choice One Dose to Foundation Consumer Healthcare LLC, which is owned by Juggernaut Capital Partners and Kelso & Co., for $675 million in cash.

Though Teva is ramping up its asset sales in an effort to preserve its credit rating and cut its massive debt load tied to its $40 billion, 2016 acquisition of Actavis Generics from Allergan plc (AGN) - Get Report .

Anaylsts have said there is no longer a "clear path" for the company to return to growth in a "timely manner."

Teva is in the process of restructuring the Actavis acquisition and seeking buyers for various non-core assets, including its European oncology and pain products and its global women's health business, Fitch Ratings said in August.

This restructuring and asset selloff, paired with cost reduction and debt payment with FCF, could be paramount to Teva's deleveraging. Management has identified $2 billion in asset sales by the end of 2017.

"Teva's progress on divestitures so far appears quite good," wrote Evercore ISI analyst Umer Raffat in a note following the sale of the women's health business in September.

Raffat pointed out that around $6 billion of Teva's debt is linked to covenants. "Divestitures will likely cover well over half of this total," he wrote. "In other words, Teva technically needs ~2 quarters of cash flows (starting from Jul 2017) to supplement this divestiture money and effectively retire the debt covenants if it chose to."

Teva's Actavis buy occured when the generics industry was on a tear and Teva's stock was hovering around $60 per share. Generic prices have since fallen.

Israel's Teva is a long-standing company with a rich history. Teva was founded in 1901 in Jerusalem as small wholesale drug business run by Chaim Salomon, Yitschak Elstein and Moshe Levin (pictured above, left to right). in 1935, Salomon, Levin and Elstein opened a small pharmaceutical plant called Assia (Aramaic for doctor) in Petah Tikva. Soon after the company would be merged with several others to form the modern day iteration (albeit a lot smaller) of Teva.

As for Mylan the approval is a huge boon for a company that has struggled more with public perception than with financial issues over the past year after its Epi-Pen scandal.

"The FDA approvals ... mark another significant milestone for our company, reinforce our proven capabilities in bringing complex and difficult-to-manufacture products to market, and further our commitment to providing access to high quality medicines," said Mylan CEO Heather Bresch.

Analysts were pleasantly surprised.

"After downplaying the possibility of a September approval and taking Copaxone out of its 2017 estimates, Mylan unexpectedly received FDA approval of both doses (40 mg 3x/week injection, and 20 mg/daily injection)," wrote Mizuho Securities USA LLC analyst Irina R. Koffler in a note Wednesday.

--Armie Lee contributed to this report

Stock quotes in this article: MYLTEVA, AGN

Here's a look back at Teva's history

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