GSK’s Blenrep Underwhelms FDA Panel Over Dose Risk-Benefit Balance In Myeloma; Retail Traders Stay Optimistic

Retail chatter around GSK picked up on Thursday after Blenrep, one of its cancer drugs, hit a roadblock with U.S. regulators.

A U.S. advisory panel said the benefits of the treatment did not appear to outweigh the risks at the proposed dose for adults with relapsed or refractory multiple myeloma.

The disease is a type of blood cancer that returns or is difficult to treat even after a successful initial treatment. 

The vote is non-binding but the agency is expected to make a decision by July 23.

The adverse verdict did not come as a surprise, as a briefing document posted by FDA staffers on Tuesday highlighted "high rates of ocular toxicity" observed in those enrolled in GSK’s two phase 3 studies. The stock shed 1.2% on Tuesday before staging a recovery in the next session.

On Thursday, GSK’s U.S. shares closed down 4.7% at $36.47 on Thursday, before inching up 0.1% to $36.51 in after-hours trading.

Blenrep was previously approved in the U.S. as a monotherapy for a fifth-line treatment of multiple myeloma but was yanked off the market in 2022 after it failed a confirmatory trial.

GSK said Thursday it continues to believe Blenrep has potential. It also noted that new treatments are needed for these patients, particularly those who have already been through standard treatment. 

The drug is already approved in the UK, Japan and a number of other countries, following trial results which showed it helped patients stay longer without their disease progressing.

In one study, called DREAMM-7, people on the Blenrep combination lived nearly three times longer without disease progression, at 36.6 months compared to 13.4 months for those on a standard regimen.

 It also showed a 42% lower risk of death after more than three years of follow-up.

In another trial (DREAMM-8), patients who were more heavily pretreated and had fewer options also saw strong results. 

The median progression-free survival was 32.6 months on the Blenrep combo compared to 12.5 months on the alternative. 

While the overall survival benefit wasn’t yet statistically significant, the trend favored Blenrep.

On Stocktwits, retail sentiment for GSK was ‘bullish’ amid ‘high’ message volume.

One user described GSK as a “huge buying opportunity,”  while another noted they were initiating a starter position in the stock. 

GSK’s U.S. stock has risen 7.4% so far in 2025.

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