Shares of Five Prime Therapeutics $FPRX were crushed on Tuesday as word spread about their abstract released ahead of the Society for Immunotherapy of Cancer meeting this weekend detailing the first snapshot of data on a small group of pancreatic cancer patients treated with cabiralizumab and Opdivo.
In what turned out to be a nasty surprise for analysts, the abstract detailed an objective response rate of 10%, with three partial responses and a 6-month disease control rate of 13%. But the backlash also centered on the troubling safety data among 205 patients with solid tumors, with a 43% rate of Grade 3 to 5 (death) adverse events in the study which triggered a discontinuation rate of 13%.
That profile pushed the stock over the cliff and down 41% by the end of the day. And Five Prime is hosting an investor call this morning to see if it can reverse the tide.
The reaction is bad news for Bristol-Myers Squibb, which paid Five Prime $350 million upfront two years ago to partner on Five Prime’s colony stimulating factor 1 receptor (CSF1R) antibody program, which included cabiralizumab (FPA008) as the lead in the clinic. The deal overall was worth up to $1.74 billion.
The early-stage trial numbers were worse than expected, said Jefferies’ Eun Yang, with a weaker efficacy profile and a damaging set of safety figures. “While the data is not as strong as we like to see,” Yang added, “this compares reasonably to chemo combo in 2L PC.”
Leerink’s Michael Schmidt, on the other hand, rather liked the response data but fretted about safety. He noted:
That said, we think the safety profile disclosed in the abstract, including Grade 3-5 treatment-emergent adverse events (TEAE) seen in 43% of patients needs to be better understood and could raise some investor questions until the full dataset is provided at SITC next weekend.
We’ll be at SITC over the weekend for an update on the data from Five Prime.
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