Immutep recruits more patients for non-small cell lung cancer trial, banks milestone payment from GlaxoSmithKline

Immutep ASX IMM Phase II clinical trial positive interim data immunotherapy cancer
The requisite number of predefined patient responses in cohort one of Part A of Immutep's TACTI-002 phase II clinical trial was exceeded.

Sydney-based biotechnology company Immutep (ASX: IMM) has reported a successful roll-out to part A of its TACTI-002 phase II clinical trial for patients with previously-untreated, inoperable or metastatic non-small cell lung cancer.

The company today confirmed it had achieved the required number of predefined patient responses in cohort one of part A and would proceed with the recruitment of an additional 19 patients for cohort two, bringing the total number of patients in part A to 36.

Up to 13 clinical trial sites across the US, Europe and Australia are involved in the study, which doses patients with a therapeutic combination of Immutep’s lead product candidate eftilagimod alpha with immunotherapy drug Keytruda (or pembrolizumab).

Keytruda is a prescription medication developed by US pharmaceutical giant and TACTI-002 trial partner Merck & Co to help a patient’s immune system fight certain cancers.

Response rates

In part A of the trial, seven out of 17 patients (or 41.2%) in cohort one displayed a partial response after dosing with the immunotherapy treatment, as determined by industry-standard RECIST 1.1 (Response Evaluation Criteria in Solid Tumours) framework.

RECIST is a set of published rules which define when tumours in cancer patients improve (respond), stay the same (stabilise), or worsen (progress) during treatment.

An additional six patients in cohort one displayed a stabilisation of disease while 12 patients are currently continuing treatment.

Checkpoint protein status

Patients were allowed to participate in the trial regardless of their PD-L1 status – a checkpoint protein which can halt or limit the development of the T-cell response and which is a well-known predictive marker for response to pembrolizumab in non-small cell lung cancer.

“While the response rate of pembrolizumab in non-small cell lung cancer patients with greater than or equal to 50% PD-L1 expression is approximately 40%, [the response rate] is between 15% to 20% in patients with PD-L1 expression of between 1% and 49% on the tumour,” Immutep reported.

“Patients with no PD-L1 expression are expected to benefit significantly less than that.”

Immutep said best overall response (BOR) numbers for cohort one would not be available until the final patient enrolled in June had been on the study for six months and undergone radiological assessment.

Meanwhile, recruitment is ongoing for part B of the trial (targeting patients with second line non-small cell lung cancer) and part C (patients with second line head and neck squamous cell carcinoma).

GlaxoSmithKline trial

This week, Immutep confirmed it would receive a $7.4 million milestone payment from pharmaceutical corporation GlaxoSmithKline prior to the commencement of GSK’s phase II clinical trial evaluating the safety, tolerability, efficacy and dose-response of the GSK2831781 drug on 280 patients with ulcerative colitis.

The trial will consist of a five-week screening window, 10-week induction phase, 20-week extended treatment phase and 12-week follow-up phase with final results expected in early 2022.

Licence agreement

GSK2831781 is derived from Immutep’s IMP731 antibody – a depleting anti-LAG antibody technology exclusively licensed to GSK in 2010.

Under the terms of the licensing agreement, GSK is responsible for all costs associated with the drug’s clinical development and Immutep will be eligible for up to $118 million in milestone payments and royalties if it is commercialised.

Immutep chief executive officer Marc Voight welcomed the GSK trial.

“It is very encouraging to see GSK advancing their product candidate [and] further validating LAG-3 as a potential target for therapeutics in autoimmune diseases,” he said.

“The partner milestone payments will be an important source of non-dilutive funding [for us] and the capital will be deployed to further advance our extensive development programs.”

High unmet need

Ulcerative colitis is a form of inflammatory bowel disease characterised by chronic relapsing and remitting inflammation of the colon and rectum.

According to GSK, there remains a “high unmet need for novel treatments which achieve a higher rate of efficacy in resolving [ulcerative colitis] symptoms, and inducing and maintaining mucosal healing to achieve long-term corticosteroid-free remission”.

At mid-afternoon, shares in Immutep were trading 13.04% higher at $0.026.