Can anyone explain why share prices have not fallen?

The Klein law firm just announced a class action suit: Mallinckrodt Public Limited Company allegedly made materially false and/or misleading statements and/or failed to disclose that: (i) Acthar posed significant safety concerns that rendered it a non-viable treatment for ALS; (ii) accordingly, Mallinckrodt overstated the viability of Acthar as an ALS treatment; and (iii) as a result, the Company’s public statements were materially false and misleading at all relevant times. Share prices should have plummeted, but it is on the up trend? Over 70.95%? Has the news not made mainstream news yet? If no one has found out yet it might be a very strong short opportunity.