Shares in Australian biotech Immutep rose quickly on data for its cancer immunotherapy drug eftilagimod alpha alongside Merck & Co’s Keytruda in solid tumours.
Most of those gains dissipated after the results of the mid-stage trial in non-small cell lung cancer (NSCLC) and head and neck squamous cell carcinoma of the (HNSCC) were presented at a conference in Germany in what appeared to be profit-taking.
The TACTI-002 trial is testing eftilagimod alpha or ‘efti’ in combination with Keytruda (pembrolizumab) in first and second-line NSCLC and second-line HNSCC, and demonstrated responses for the pairing across a range of patients with different levels of PD-L1 expression.
Overall, efti plus Keytruda achieved a 47% objective response rate in first-line NSCLC patients and 33% of the second-line HNSCC group, and median progression-free survival (PFS) hadn’t been reached at the data cut-off, more than seven months into the study.
Analyst Dr Chris Redhead at Goetzpartners said the data are encouraging and show the potential of efti – which targets lymphocyte activation gene-3 (LAG-3 or CD223) in combination with PD-1 inhibitor drugs.
The response rates for the combination with Keytruda are “on a par with the pembro-chemo combo [and] this potentially opens the door to a new effective first-line option”, he wrote in a research note, noting it could potentially sidestep the side effects seen with chemotherapy.
Immutep also has a phase 2b trial of efti ongoing – called AIPAC – that is testing the drug in combination with chemotherapy in metastatic breast cancer and could potentially support regulatory filings for the drug as a standalone immunotherapy.
Data is due in the next few weeks and if positive could “open the door to a substantial big pharma licensing deal”, says Redhead.
The PD-1/PD-L1 checkpoint inhibitors that hit the market in 2015 have already transformed the standard of care for some cancers, but there is still a sizeable patient population that doesn’t respond to them, and companies are seeking out new combinations that might improve results.
When given as a monotherapy, Keytruda’s benefits are mostly confined to the one-third or so of patients who have 50% or greater PD-L1 expression, says the Goetzpartners analyst, so “the results showing an almost 50% [response] across all patients at any level of PD-L1 expression are obviously extremely encouraging”.
Immutep seems to be slightly out in front among companies developing LAG-3-targeting drugs, but it has some heavyweight competition in the form of Merck, GlaxoSmithKline, Bristol-Myers Squibb and Regeneron, which all have candidates in clinical development.