Company: PHAT
Filing Date: 2025-03-06
Form Type: 10-K
Source: 0000950170-25-034183
Chunk: 38

Company: Phathom Pharmaceuticals, Inc.
Filing Date: 2025-03-06
Form: 10-K
Item: Item 1
Chunk 38
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3 times the upper limit of normal were observed in 0.4% of subjects treated with vonoprazan 20 mg and 0.2% of subjects treated with lansoprazole. In the maintenance phase, transient ALT or AST elevations greater than three times the upper limit of normal were observed in 1% of subjects treated with vonoprazan 10 mg, 0.3% of subjects treated with vonoprazan 20 mg, and 2% of subjects treated with lansoprazole.  

Vonoprazan Post-Marketing Safety in Japan and Asia

The most recent post-marketing safety report from December 2023 includes a worldwide cumulative estimate of over 60 million patients who have received vonoprazan since its approval in late 2014. Based on the post-marketing experience, the clinically significant adverse reactions section of the Japanese prescribing information for vonoprazan was updated to include shock, anaphylaxis, hepatic impairment, skin reactions such as toxic epidermal necrolysis, Steven-Johnson syndrome, and erythema multiforme; and events of pancytopenia, agranulocytosis, leukocytopenia, and thrombocytopenia. The incidence of these reactions was considered extremely rare (less than 1 in 100,000 patients) and a causal relationship to vonoprazan could not be ruled out. Although serious hepatic adverse events have been observed among patients exposed to vonoprazan in Japan in the post-marketing setting, these cases were typically confounded by comorbidities or other concomitant medications and believed to be idiosyncratic reactions. Post-marketing safety data, including the December 2023 post-marketing safety report, has been submitted to the Pharmaceuticals and Medical Devices Agency. Moreover, the final results from the VISION trial, a five-year randomized, open-label, 

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multicenter study conducted by Takeda evaluating the long-term efficacy and safety of vonoprazan compared with the PPI lansoprazole in patients with EE, further demonstrate that the safety profile of vonoprazan is generally comparable to lansoprazole.  

Vonoprazan Launch in Japan 

Vonoprazan Regulatory Status 

Vonoprazan first received approval in Japan on December 26, 2014, and was launched shortly thereafter in February 2015, as TAKEC