Immunomedics announced that it has been issued three U.S. patents, covering three of the company’s antibody-drug conjugates (ADC) that carry the SN-38 toxic payload to a number of cancers.
The patents, all part of the patent family, “Dosages of immunoconjugates of antibodies and SN-38 for improved efficacy and decreased toxicity,” will expire in July 2033.
The first patent, No 9,492,566, applies to one of Immunomedics’ most advanced ADCs, sacituzumab govitecan (IMMU-132). This is the 32nd U.S. patent protecting the use of IMMU-132 in patients with Trop-2-positive cancers (Trop-2 is a cell-surface receptor overexpressed by many tumors.)
ADCs are designed to deliver specific payloads of a chemotherapeutic directly to a tumor while reducing overall toxic effects, the company reports on its website. SN-38, the active metabolite of irinotecan, is a chemotherapeutic used.
IMMU-132 is now in clinical development in Phase 2 trials, and has shown promising objective response rates and durable responses in heavily treated patients with non-small cell lung cancers, small lung cancers, urothelial cancers, and triple-negative breast cancers, the company reported in a press release. Based on these findings, it was designed a Breakthrough Therapy by the U.S. Food and Drug Administration (FDA) as a potential treatment for advanced triple negative breast cancer.
Immunomedics then expanded its ADC program to include hematologic tumors. ACDs here have a similar composition, with the same SN-38 toxic payload and the same CL2A molecule linking the payload to the antibody, but the antibody targeting Trop-2 was replaced by an anti-HLA-DR IgG4 antibody, creating IMMU-140. (This drug is covered by the U.S. Patent No. 9,493,573.)
IMMU-140 has already shown encouraging results in a Phase 1 trial for non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL) patients, inducing responses to treatment in more than half of treated patients without reaching a maximum tolerated dose.
Additional preclinical data of IMMU-140 in five hematologic cancers — NHL, CLL, acute myelocytic, and lymphocytic leukemia, and multiple myeloma — will be presented at the Annual Meeting of the American Society of Hematology, to be held Dec. 3–6 in San Diego.
A final new patent was issued for an ADC designed to target B-cell hematologic malignancies. This drug, which has the SN-38 toxic payload linked to a humanized anti-CD19 antibody, is covered with the patent no. 9,493,574.
“We are pleased to receive these new patents, which provide extensive intellectual property protection for our robust ADC program that has the potential to address approximately 90% of all human cancers,” Cynthia L. Sullivan, company president and chief executive officer, said in a press release. That estimate, she said, was based information from the American Cancer Society.