Genprex announced that its immunogene therapy candidate Oncoprex in combination with Genentech’s Tarceva (erlotinib) demonstrated positive Phase 2 interim trial results in patients with late-stage non-small cell lung cancer (NSCLC).
The ongoing Phase 1/2 clinical trial (NCT01455389) is evaluating the drug combination at The University of Texas MD Anderson Cancer in patients with advanced NSCLC, with and without EGFR mutations, who have failed at least two previous chemotherapy regimens.
In the Phase 1 part of the trial, researchers are assessing the highest dose of Oncoprex that can be safely given in combination with Tarceva to patients with late-stage NSCLC. In Phase 2 of the study, researchers will assess whether the combination of Oncoprex and Tarceva can help to control NSCLC.
The trial will evaluate the combo treatment in up to 57 NSCLC patients, with interim results from the first nine patients evaluable to date showing that the therapy resulted in an overall disease control rate of 78 percent. This includes the rates of stable disease, partial responses, and complete responses.
A durable complete response was observed in one late-stage patient with EGFR-negative NSCLC with multiple targeted lesions, the company reported. Also, to date, one EGFR-negative patient had 24 percent regression of targeted lesions. Another EGFR-negative patient had a 30 percent regression in one targeted lesion, and 18 percent regression over all targeted lesions.
Stable disease, tumor regression, and decreased metabolic activity in multiple tumors was seen in one EGFR-positive patient, but without the T790M mutation.
Stable disease was seen in three patients. This was evident by an absence of disease progression following at least two treatments, each 21 days apart.
To date, the combo treatment has been shown to have a favorable safety profile, similar to the safety profile seen in two previous Phase 1 studies.
“These interim data suggest that this targeted therapy may provide a viable treatment option for late-stage NSCLC patients, with or without EGFR mutations, whose disease has progressed following currently available treatments,” Genprex CEO Rodney Varner said in a press release.
“If these positive interim results are sustained in either of these populations through the trial’s conclusion, we plan to ask the FDA to grant accelerated approval for this therapy,” he said.
Approximately 10 to 50 percent of NSCLC patients carry an EGFR mutation, which makes their tumors sensitive to first-generation TKIs such as Tarceva. However, patients frequently develop resistance to TKI treatment within two years, resulting in disease progression.
New-generation TKIs show promise as therapeutics for resistant EGFR-positive tumors carrying the T790M mutation, but nearly half of EGFR-positive patients do not carry this mutation. There are currently no treatment options for these patients, who generally have a poor prognosis.
Oncoprex helps transfer a gene called fus1 into cancer cells. Because fus1 is known as a tumor-suppressor gene, cells without this gene may be involved in the development of lung cancer tumors. Therefore, replacing the gene in these cells may keep the tissue from forming cancer cells.
Tarceva blocks a protein on tumor cells that may control tumor growth and survival. Oncoprex in combination with Tarceva may be an appropriate treatment for late-stage NSCLC patients.