"Another new and exciting development is with our antibody-drug conjugates (ADCs) for solid cancer therapy. Both IMMU-132 (TROP-2-SN-38) and IMMU-130 (labetuzumab-SN-38) have produced partial responses and stable disease in patients who have failed multiple prior therapies, including irinotecan, the parent drug of SN-38. While IMMU-130 is focused on colorectal cancer, IMMU-132 has produced partial responses in very advanced colorectal, triple negative breast and small cell lung cancer patients. Both programs have entered into Phase II clinical development," Ms. Sullivan added.
"In all, more than 80%, or 20 of the 24 assessable patients, showed evidence of disease control with stable disease or partial responses achieved with IMMU-132 in the Phase I trial just completed. Impressively, this includes 8 patients who had failed prior irinotecan-containing therapies. Because irinotecan is the parent of SN-38, we postulate that the increased amount of SN-38 delivered to the tumors by our ADCs overcomes the tumor's resistance to this class of drugs," commented Dr. William A. Wegener, Senior Vice President of Clinical Research, in his summary of the year's clinical developments focusing on the Company's two most exciting programs, one in pancreatic cancer and the other in solid cancers with our antibody-SN-38 conjugates.
"In terms of time-to-progression for the IMMU-132 program, of the 20 patients who reported a partial response or stable disease as their best response, the duration ranges were from 4.5 weeks to more than 35 weeks, with 7 patients continuing with their treatments. The ability to achieve some measure of disease control with this ADC by itself is impressive, since this is a group of heavily pretreated patients with few other therapeutic options. To date, there have been no anti-antibody or anti-SN38 immune responses in patients treated with IMMU-132, even with long-term therapy. Major side effects are neutropenia and diarrhea, with minor side effects being fatigue and alopecia," concluded Dr. Wegener.