CELC Stock Records Worst Day Ever After Late-Stage Breast Cancer Trial Results — What’s Driving The Selloff?

• The data show that the drug, in combination with others, reduced the risk of disease progression or death by about 50%.
• Celcuity said the results mark the first time a Phase 3 trial has shown one drug of this class clearly outperforming another in the specific patient group. 
• The company plans to file a supplemental application to the FDA later this year based on the new data.

Shares of Celcuity Inc. (CELC) tumbled 26% on Tuesday after the company reported patient deaths in a late-stage trial of its experimental drug, gedatolisib, in advanced breast cancer, despite it reducing disease progression overall.

The Minneapolis-based biotechnology company announced detailed results from a major late-stage study of its experimental drug gedatolisib in patients with a common form of advanced breast cancer. The trial tested two combinations of gedatolisib — one with the hormone blocker fulvestrant and the targeted drug palbociclib (the “triplet”), and one with just fulvestrant (the “doublet”) — against the current standard of alpelisib plus fulvestrant.

One patient receiving the gedatolisib triplet died from a treatment-related side effect, the company said, while adding that investigators linked it to the palbociclib component. By comparison, two patients on the standard alpelisib-plus-fulvestrant regimen experienced treatment-related fatal side effects. No treatment-related deaths occurred among patients on the gedatolisib doublet, it added.  

Positive Takeaways From The Trial

In patients whose tumors had a specific PIK3CA mutation, both gedatolisib regimens roughly doubled the time patients lived without their cancer worsening. Median progression-free survival reached 11.1 months with the triplet and 11.3 months with the doublet, compared with 5.6 months for alpelisib plus fulvestrant. That translated to a 50% lower risk of disease progression or death for the triplet and a 49% lower risk for the doublet.

Tumors shrank in 48.9% of patients on the triplet and 35.7% on the doublet, versus 26% on the standard treatment. Responses also lasted longer with gedatolisib: a median of 15.7 months for the triplet and 24.2 months for the doublet, compared with 7.5 months for alpelisib plus fulvestrant.

Overall survival data from the trial remain immature—meaning follow-up is too short for final conclusions—but early trends favored both gedatolisib regimens over the current standard treatment, the company said.

The safety profile was generally consistent with earlier data, the company said. The most common serious side effects in the gedatolisib triplet were a drop in infection-fighting white blood cells (neutropenia) and mouth sores. Overall, few patients stopped treatment because of side effects — about 2.6% in the triplet group and 3.8% in the doublet group, versus 7.1% in the alpelisib group.

Celcuity said the results mark the first time a Phase 3 trial has shown one drug of this class clearly outperforming another in this patient group. The company is also developing gedatolisib for patients without the PIK3CA mutation and has already filed for U.S. approval in that larger group for which a decision is expected in July. The company also plans to file a supplemental application to the FDA later this year based on the new data.

How Did CELC Retail Traders React?

On Stocktwits, retail sentiment around CELC stock rose from ‘neutral’ to ‘extremely bullish’ territory over the past 24 hours, while message volume jumped from ‘low’ to ‘high’ levels.

A Stocktwits user termed the data readout as “great,” while terming the stock reaction as “super inordinate.”

Another user highlighted several upsides, including the upcoming FDA decision on the drug in patients with certain forms of breast cancer.  

CELC stock has gained about 687% over the past 12 months. 

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