CHICAGO (TheStreet) -- The knock on ImmunoGen (IMGN) has long been that early success with its "smart bomb" cancer drug delivery technology wasn't being replicated. At this weekend's ASCO meeting, however, the company's lead pipeline drug IMGN853 posted impressive responses in a segment of hard-to-treat ovarian cancer patients.
The perception that ImmunoGen can't develop a drug successfully on its own will probably improve Monday when post-ASCO trading kicks in.
Buoyed by the results presented at the ASCO meeting this weekend, ImmunoGen plans to launch a study later this year which, if positive, could be used to seek approval of IMGN853 as a treatment for advanced ovarian cancer.
IMGN853 consists of a monoclonal antibody designed to seek out and attach itself to tumors with large quantities of a protein, folate receptor alpha, on their surface. The IMGN853 antibody carries a toxic chemotherapy payload, which is released into the tumor once attached.
The analysis of a phase I study presented on Saturday, encompassed 22 women with folate-positive ovarian cancer that had grown resistant to standard, platinum-based chemotherapy. The median number of prior ovarian cancer treatment regimens was four, with some patients undergoing as many as 12 prior treatments.
Among the 17 patients evaluable for efficacy, the response rate to IMGN853 was 53%, including one complete response and eight partial responses. When ASCO abstracts were released two weeks ago, the IMGN283 response rate was 40%.
While only a small number of patients were analyzed, the IMGN853 response rate compares well to response rates in the 20% range typically seen from various chemotherapy regimens used in heavily pre-treated ovarian cancer patients.