Viralytics reports strong interim results for cancer treatment

Viralytics (ASX:VLA) has announced strong interim results for a phase 2 clinical trial of its lead product Cavatak in late-stage melanoma patients.

Cavatak is a naturally occurring genetically unaltered virus (coxsackievirus A21), which acts by binding to the ICAM-1 receptor that overexpressed on the surface of many cancer cell types.

Interim data from the first 35 patients in the CAvatak in Late-stage Melanoma (CALM) study was presented by lead investigator Dr Robert Andtbacka from the Huntsman Cancer Institute in the USA, at the 8th World Congress of Melanoma held in Germany this week.

The data shows solid progress is being made towards achieving the primary endpoint of the study and strengthens the evidence that Cavatak is well tolerated in late-stage melanoma patients.

The primary endpoint for the study is immune-related progression free survival (irPFS) at 6 months after the first dose of Cavatak; that is, the length of time during and after treatment that study participants live with the cancer without it worsening. This includes participants who achieve a complete tumour response, partial tumour response or have stable disease.

Currently, 23 patients have been assessed for irPFS at 6 months, 8 (35%) of whom have achieved this endpoint. The trial target will be realised if 10 of 54 patients meet the primary endpoint.

Thirty patients enrolled in the study qualified for assessment of the irPFS endpoint at 12 weeks and 18 (60%) had achieved an irPFS at 12 weeks, with seven currently between the 12 week and 6 months response monitoring timepoints.

A further measure in the trial to assess Cavatak activity is the best overall tumour response, which assesses injected and non-injected tumours. In the 30 patients who have been on the study for at least 12 weeks, a complete or partial tumour response has been seen in two and six patients, respectively (8/30 or 27%).

Five patients have entered the extension study and received further doses of Cavatak. Two patients who have been on the study for 12 months have completed the extension study - both achieved a partial response. Follow-up surgery to remove the residual injected tumour tissue resulted in a complete surgical response in both patients.

The independent Data Monitoring Committee (DMC) of the trial recently reviewed data from the first 35 patients in the study (stage 1) and reported that Cavatak had met safety and tolerability criteria. The study is now progressing into stage two and full enrolment of 63 patients.

There are currently 38 patients enrolled in the study and it is estimated that study may be fully enrolled by the end of 2013.

Dr Andtbacka commented: “These interim results with Cavatak are encouraging and it is pleasing to see activity in both injected and metastatic tumours. Oncolytic immunotherapy is a promising new class of investigational agents with potential future application either as a monotherapy, a pre-treatment prior to surgery or use in combination with other new frontline therapies.”

Viralytics shares were trading 16.7% higher at $0.28 as of around 2 pm on Friday.