July 28 (Reuters) - Shares of AcelRx Pharmaceuticals Inc plunged nearly 28 percent in premarket trading, after the U.S. Food and Drug Administration rejected its pain drug device, Zalviso, late on Friday.
Analysts said they expected the product to eventually receive approval as the issues cited in Zalviso's "rather mild" complete response letter were requests for additional information largely around the device.
AcelRx said it would resubmit its marketing application for Zalviso by the end of the year, pending further discussions with the FDA.
The needle-free, handheld, patient-controlled system is designed for the management of moderate-to-severe pain in adult patients in a hospital setting.
Zalviso, consists of sufentanil, an opioid, and is delivered using AcelRx's flagship NanoTab technology which enables rapid absorption when placed under the tongue.
In its complete response letter to the company, the agency did not ask for any additional efficacy trials but requested additional information to ensure proper use of the device.
Canaccord Genuity analyst John Newman cut his rating on the stock to "hold" from "buy" and halved his price target to $8 based on "on the unexpected magnitude of delay for Zalviso and concerns over stability/shelf life" of the product.
Roth Capital Partners, Mizuho and JMP Securities analysts said the rejection would likely result in a one-year delay to approval as the FDA's requests were readily addressable.
The FDA sought changes to the instructions for use for the device and additional data to support its shelf life.
"ACRX was surprised to receive a CRL for issues it believes could have been resolved with a routine (review) PDUFA delay; almost exclusively straightforward device/instruction issues rather than drug concerns," JMP analyst Oren Livnat said.
"This increases our overall confidence in approvability, albeit after an unfortunate delay," Livnat said, maintaining his "market outperform" rating on the stock.
The delay bodes well for the The Medicines Company whose rival experimental pain product Ionsys will now likely gain a timing advantage. The company submitted an application to market the treatment in late June.
"Thus, assuming a first-pass approval, Ionsys now appears to have at least a 2-month head start on Zalviso," Roth Capital Partners analyst Ed Arce said, cutting his price target on the stock to $16 from $22.
RBC Capital Markets analysts reduced their 2021 U.S. sales forecast for Zalviso by $50 million to $350 million.
An application to market Zalviso in Europe was submitted by the company's German partner Grunenthal Group earlier in July.
The product is also undergoing development for use in breakthrough pain in cancer patients, pain relief for patients undergoing procedures in a physician's office and acute pain.
Four brokerages - Roth Capital Partners, JMP Securities, Mizuho and RBC Capital - kept their positive ratings on the stock.
The Redwood City, California-based specialty pharmaceutical company's stock was trading at $7.77 premarket on Monday after closing at $10.83 on the Nasdaq on Friday. (Reporting by Natalie Grover in Bangalore; Editing by Saumyadeb Chakrabarty)