Positive safety data reported from Immutep’s clinical trial to treat metastatic melanoma

Immutep ASX IMM TACTI-mel Melanoma tumour shrinkage Phase I clinical study Keytruda metastatic melanoma
Tumour shrinkage was observed in up to 66% of the 24 patients treated.

Biotechnology company Immutep (ASX: IMM) has reported “mature positive efficacy data” from a phase I clinical study combining lead drug candidate eftilagimod alpha with Keytruda in the treatment of metastatic melanoma.

The TACTI-mel (Two ACTive Immunotherapies in melanoma) trial evaluated the combination of eftilagimod with anti-PD-1 therapy Keytruda (or pembrolizumab) in 24 patients with late-stage melanoma.

PD-1 (or programmed death-1) proteins are part of a group of checkpoint inhibitors expressed on the surface of immune and cancer cells.

Approximately 75% of patients in the trial were classified as M1c (associated with lowest probability of survival), 67% had lung metastasis, 50% had liver metastasis, 50% had elevated LDH (poor prognosis marker) and many had either a suboptimal response or disease progression and were using pembrolizumab treatment on its own.

All patients received subcutaneous injections of eftilagimod every two weeks, with a treatment duration of up to either six or 12 months.

The primary endpoint of the trial was safety and tolerability, with the outcome to determine the recommended dose for a phase II trial.

The trial also evaluated efficacy through overall response rate (ORR), tumour shrinkage and disease control rate (DCR).

Favourable profile

Immutep chief scientific officer Dr Frédéric Triebel said the trial found that eftilagimod has a favourable safety profile in combination with pembrolizumab with no dose-limiting toxicities.

“The combination therapy shows very encouraging efficacy signals along with a favourable safety profile so far in this high-risk patient population,” he said.

“Patients are responding well to the combination treatment, their tumours are shrinking and not growing back over a long follow up period and we have seen the complete disappearance of all target tumour lesions for six patients plus one patient with a metabolic complete response on the PET-scan.”

Open label trial

TACTI-mel is a multi-centre, open label clinical trial involving four cohorts of six patients per cohort.

Part A includes the first three cohorts testing 1 milligram, 6mg and 30mg dosages of eftilagimod in combination with pembrolizumab, with eftilagimod treatment given for six months only and commencing at cycle five of pembrolizumab treatment.

Part B includes the remaining cohort testing a 30mg dosage of eftilagimod given for 12 months in combination with pembrolizumab, starting on the first day of pembrolizumab treatment.

Research payment

Last week, Immutep received a $2.5 million research and development tax incentive payment from the French Government under its Crédit d’Impôt Recherche scheme.

The incentive allows French companies conducting research and development activities in Europe to be reimbursed 30% of their eligible expenditure.

Immutep qualifies to receive CIR tax incentive through research conducted in its Paris-based laboratory by subsidiary Immutep SAS.

The incentive funds will be used to support the planned global clinical development of eftilagimod.