ACTR-02. DCC-2618, A NOVEL pan-KIT AND PDGFRa KINASE SWITCH CONTROL INHIBITOR, SHOWS ENCOURAGING SIGNAL IN A PATIENT (PT) WITH GLIOBLASTOMA (GBM)

Abstract

BACKGROUND

Non-clinical data suggest that PDGFRa plays an important role in the development and progression of human gliomas. To date, few PDGFRa inhibitors with CNS activity have been available. DCC-2618 was designed to potently inhibit the broadest range of mutations (mut) in KIT & PDGFRa kinases that emerge during tumor progession or on treatment.

METHODS

In a dose-escalation study (NCT# 02571036) of oral DCC-2618 (QD or BID q28 days), pts with advanced malignancies with a molecular rationale for activity were eligible. MRI scans were performed initially every 2 cycles then every 3 cycles.

RESULTS

We enrolled 4 GBM pts and 1 anaplastic astrocytoma (AA) pt with PDGFRa muts/ amplifications who had progressed after standard temozolomide chemoradiation (GBM) or temozolomide only (AA) and had received 0 to 5 salvage therapies. Three pts (2 GBM and 1 AA) had a triple amplification of PDGFRa, KIT and KDR (4q12 amplicon). Two GBM pts had activating PDGFRa mutations. Pts were treated at 20 mg (1 pt), 50 mg BID (2 pts) or 100 mg QD (2 pts). The per-protocol population (N=48) received doses up to 200 mg BID and DCC-2618 was well tolerated. One GBM pt with mut PDGFRa progressed after 6 weeks and one stopped treatment due to a tumor-related hemaorrhage on C1D12. Two of the three pts with triple amplifications progressed after 2 cycles while the third pt (GBM, 20 mg BID) achieved a PR per RANO after 9 cycles. This pt is currently in cycle 20 with a remarkable 94% tumor reduction.

CONCLUSIONS

The durable partial response of >18 months in a GBM patient (94% tumor reduction) warrants further evaluation of DCC-2618 in gliomas. An expansion cohort for pts with KIT- and PDGFRa driven tumors was initiated to be able to better select the patient population with a likely benefit.