Traws Pharma (NASDAQ:TRAW) shares fell sharply in premarket trading on Monday after the company revealed that UK regulators had delayed a planned mid-stage clinical trial for its influenza treatment candidate.
The setback adds to previous regulatory challenges facing the programme and prompted investors to reassess the drug’s development timeline.
MHRA Issues Negative Assessment
Late on Friday, Traws Pharma announced that the UK Medicines and Healthcare Products Regulatory Agency (MHRA) had issued an unfavourable review of the proposed human challenge study for tivoxavir marboxil.
As a result, the company said the trial has been deferred while it evaluates next steps for the programme.
Human challenge studies involve intentionally exposing participants to a pathogen under controlled conditions to assess the effectiveness of an investigational treatment.
Shares Fall in Premarket Trading
Following the announcement, Traws Pharma stock declined 17% in premarket trading as investors reacted to the regulatory setback.
The delay introduces additional uncertainty around the development path and timing for tivoxavir marboxil, which has been one of the company’s key clinical-stage assets.
Company Advances Alternative Candidates
Despite the delay, Traws Pharma said it continues to progress alternative drug candidates designed to replicate the original therapy’s long-acting characteristics and antiviral potency.
According to the company, these backup programmes are being developed without the mutagenic concerns that have drawn scrutiny from regulators.
Regulatory Concerns Mirror Earlier FDA Action
The decision by UK authorities follows a similar move by U.S. regulators earlier this year.
In February, the U.S. Food and Drug Administration placed a clinical hold on Traws Pharma’s investigational new drug application for tivoxavir marboxil, citing concerns related to the mutagenicity data package submitted by the company.
Mutagenicity refers to a substance’s potential to cause genetic mutations, a factor that can present significant safety considerations during the drug development process.
Development Focus Shifts to Next Steps
With regulatory concerns now raised by both UK and U.S. authorities, investors will be closely watching how Traws Pharma addresses the issues surrounding tivoxavir marboxil and whether its alternative candidates can maintain the company’s progress in developing new influenza treatments.
The latest development highlights the regulatory hurdles often faced during clinical-stage drug development, particularly when safety-related questions emerge during the review process.