As Phathom Pharmaceuticals approaches the one-year anniversary of Voquezna's FDA approval to treat Helicobacter pylori infection, the regulatory blows keep coming.
Late this week, Phathom said it received complete response letters (CRLs) from the FDA relating to both its ongoing drug application in erosive esophagitis and its post-approval supplement for its H. pylori license.
The letters “formalize” the FDA’s request for Phathom to generate additional stability data proving that levels of a potential cancer-causing agent in the drug will consistently remain at or below the daily acceptable intake limit of 96 nanograms, the New Jersey-based company explained.
After testing last summer uncovered trace levels of a suspected carcinogen in commercial batches of Phathom’s Voquezna, the FDA in January said it wouldn’t act on the drug’s application in erosive esophagitis by its target action date of Jan. 11. Meanwhile, in the drug's approved use, Voquenza's launch is on hold.
As for the official FDA slap-downs this month, Phathom is eyeing a quick recovery. The company expects to meet with the FDA sometime before the end of March to discuss a resubmission plan and timeline. It believes this approach “will lead to approval and launch of products containing vonoprazan," the company said in a statement.
The CRLs aren’t expected to weigh heavily on the company’s business overall, a company spokesperson added.
“Our cash position is strong, and no layoffs are planned based on the issuance of the CRLs,” the spokesperson said. “[W]e continue to work closely with the FDA and look forward to making vonoprazan available to patients as soon as possible.”
The company says it has investigated the cause of the impurity and has rolled out mitigation measures to ensure the drug stays within the FDA threshold.
Phathom achieved regulatory victory with vonoprazan some three years after its spinoff from Takeda.
Last May, the FDA cleared vonoprazan in two combinations to treat H. pylori infection, which typically affects the stomach or the small intestine. Takeda had already been selling the therapy in several Asian markets.
Voquezna Dual pak combines vonoprazan—a novel potassium-competitive acid blocker—with the antibiotic amoxicillin, while Voquezna Triple Pak further adds clarithromycin to the vonoprazan-amoxicillin duo.
Phathom had originally planned to launch the products in 2022’s third quarter.
Shortly after those bacterial infection approvals, however, the company in August revealed that nitrosamine testing picked up "trace levels" of the impurity in the newly approved product.
Elsewhere, nitrosamines have been a thorn in countless drugmakers’ sides in recent years. The compounds, which are found in everyday items like water and food, have triggered large recalls, shortages and product pulls across the industry.