Phathom Pharma Climbs 45% In 4 Days As Lead Drug Advances Into Phase III

(RTTNews) - Shares of Phathom Pharmaceuticals Inc. (PHAT) have gained an impressive 45% over the last four trading days, thanks to the progress in the development of its lead and sole drug Vonoprazan.

Vonoprazan is a potassium-competitive acid blocker (P-CAB), a new class of medicine that blocks acid secretion in the stomach. Developed by Takeda, Vonoprazan is approved in nine countries in Asia and Latin America for the treatment of acid-related diseases which include reflux esophagitis, GERD, H. pylori eradication, erosive esophagitis, and peptic ulcer disease. Phathom Pharma in-licensed the U.S., European, and Canadian rights to Vonoprazan from Takeda in late May 2019.

Early this month, Phathom announced the initiation of a pivotal phase III clinical trial of Vonoprazan for both the healing and maintenance of healing of erosive esophagitis (EE) as well as the relief of heartburn, dubbed PHALCON-EE.

The PHALCON-EE trial is designed to enroll approximately 1,000 patients with erosive esophagitis in the U.S. and Europe.

The first phase of the trial will evaluate the efficacy and safety of Vonoprazan 20 mg administered once-daily (QD) compared to *Lansoprazole 30 mg QD for the healing of EE for up to eight weeks. The second phase of the trial will evaluate the efficacy and safety of Vonoprazan 10 mg QD and 20 mg QD compared to Lansoprazole 15 mg QD for the maintenance of healing of EE for 24 weeks. Both phases will also evaluate heartburn symptoms. (Lansoprazole, sold under brand name Prevacid, which belongs to the class of Proton Pump Inhibitors, is used to treat and prevent stomach and intestinal ulcers, erosive esophagitis, and other conditions involving excessive stomach acid such as Zollinger-Ellison syndrome).

On Monday (Dec.23), the Company initiated another pivotal phase III trial of Vonoprazan, dubbed PHALCON-HP. This study will evaluate Vonoprazan in combination with Amoxicillin against Vonoprazan in combination with Amoxicillin and Clarithromycin for the successful eradication of H. pylori infection.

The PHALCON-HP trial is expected to enroll approximately 975 patients with H. pylori infection. Participants will be randomized 1:1:1 to one of three arms - Vonoprazan 20 mg administered twice a day (BID) and Amoxicillin 1g administered three times a day (TID); Vonoprazan 20 mg BID, Amoxicillin 1 g BID and Clarithromycin 500 mg BID; and Lansoprazole 30 mg BID, Amoxicillin 1 g BID, and Clarithromycin 500 mg BID.

Topline data from both the PHALCON-HP and PHALCON-EE studies are expected in 2021.

The proton pump inhibitor, or PPI, class, which includes drugs like Prilosec (omeprazole), Nexium (esomeprazole), and Prevacid (lansoprazole), has been the standard of care for the treatment of acid-related gastrointestinal diseases. If approved, Vonoprazan has the potential to be the first gastric anti-secretory agent from a novel class approved in the United States, Europe, or Canada in over 30 years.

Phathom Pharma's common stock made its debut on the Nasdaq Global Market under the ticker symbol "PHAT" on October 25, 2019, at an opening price of $22.50. PHAT has thus far hit a low of $18.51 and a high of $28.51. The stock closed Monday's trading at $27.06, up 15.59%.