Immutep Ltd (ASX: IMM) shares are having a day to forget on Thursday.
In morning trade, the ASX healthcare stock is down a whopping 47% to a 52-week low of 23 cents.
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Why is this ASX healthcare stock crashing?
Investors have been racing to the exits today in response to the release of topline results from the TACTI-003 Phase IIb Trial.
That trial is evaluating eftilagimod alfa (efti) in combination with anti-PD-1 therapy Keytruda (pembrolizumab) as first-line treatment of recurrent/metastatic head and neck squamous cell carcinoma patients (1L HNSCC).
According to the release, the trial enrolled 171 patients with any PD-L1 expression at over 30 centres across the United States, Europe, and Australia.
The ASX healthcare stock advised that its MHC Class II agonist in combination with Keytruda led to higher overall response rates in evaluable patients according to RECIST 1.1.
Cohort A achieved a 31% overall response rate (ORR) and 75.9% disease control rate (DCR) in 29 evaluable patients. As a comparison, a Keytruda monotherapy achieved an 18.5% ORR and 59.3% DCR in evaluable 27 patients.
Management advised that response rates improved for Cohort B patients. However, the data for these patients will be delivered next month.
'Encouraging'
Dr. Martin Forster, from the UCL Cancer Institute and University College London Hospital NHS Foundation and TACTI-003 Investigator, said:
It is encouraging to see efti safely drive higher response rates in combination with KEYTRUDA in the first line setting for head and neck squamous cell carcinoma patients, regardless of HPV status and levels of PD-L1. The strong, consistent response rates, irrespective of whether patients have high, low, or negative PD-L1 expression, is intriguing and offers a glimpse into this novel combination's ability to improve patients' clinical responses and expand patient populations that benefit from anti-PD-1 therapy.
The ASX healthcare stock's CSO, Dr. Frederic Triebel, adds:
We are pleased with the quality of responses. Once again, durability is tracking well driven by the complementary nature of these two unique immunotherapies in fighting cancer. Efti's distinct activation of dendritic cells as an MHC Class II agonist and the resulting engagement of multiple facets of the adaptive & innate immune system has consistently translated into promising duration of responses in combination with immune checkpoint inhibitors across multiple oncology indications.
So why the selling?
The selling may have been driven by the absence of a p-value in the announcement.
The p-value is defined as the probability that the observed effect within the trial or study would have occurred by chance if there was no true effect.
Immutep has included p-values in the past. So, investors may be concerned that it was omitted because the trial didn't achieve statistical significance. This essentially would make the trial a dud.
Investors will no doubt be eagerly awaiting next month's update on cohort B.
