Goodwin Biotechnology, Inc., a biological contract development and manufacturing organization (CDMO) that specializes in bioprocess development and CGMP manufacturing of biopharmaceuticals utilizing mammalian cell culture expression systems and bioconjugation technologies, was selected by Panacea Pharmaceuticals, Inc. to develop a proof-of-concept conjugation of a fully-human monoclonal antibody to a radionuclide chelator to generate an antibody-chelator conjugate. The conjugate is subsequently labeled with indium-111 (¹¹¹In) and other potential radioisotopes for in vivo diagnostic imaging and treatment of cancers.

“Panacea has developed a fully human antibody directed against the tumor-specific marker, human aspartyl (asparaginyl) β-hydroxylase (HAAH),” said Dr. Steven A. Fuller, PhD, Chief Operating Officer at Panacea Pharmaceuticals.  “Based on the experience that Goodwin Biotechnology has in the area of Bioconjugation, they were selected to optimize, scale-up, and manufacture this antibody-chelator conjugate, of one of our lead cancer products.”

“Our initial efforts were focused on the classical random conjugation of the ‘naked’ antibody that Panacea Pharmaceuticals supplied and comparing DOTA and CHX-A’ chelators as the linkers,” noted Muctarr Sesay, PhD, Chief Scientific Officer and VP, Bioconjugation Development at Goodwin Biotechnology, Inc. “However, the results were less than desirable, based on the ability of the conjugates to bind to the antigen and incorporation of Indium¹¹¹. After a thorough analysis, we recommended a new strategy using our proprietary, site-directed conjugation process that shifted the linker away from the antigen binding site (hypervariable region) on the antibody. Results from the site-directed conjugation process, when compared to the random conjugation process, it was clear that the site-directed approach was significantly superior to the random conjugation.”

“We are extremely happy that the highly skilled scientists at Goodwin Biotechnology found a way to make a viable conjugate,” said Hossein Ghanbari, PhD, Chairman & CEO/CSO of Panacea Pharmaceuticals, Inc. “When we first evaluated the random conjugation results, we were seriously considering going back to the drawing board and developing a new antibody. Finding a solution to this significant challenge saved us years of development work and a significant amount of money.”

 “Now, based on promising preclinical animal study results with syngeneic mouse models, we’re working with Goodwin Biotechnology to continue development and optimization of the antibody-chelator conjugates via site-directed conjugation and will proceed to manufacture the product for additional preclinical studies and human clinical trials,” added Dr. Fuller. “It is clear that the decision to select Goodwin Biotechnology has paid off well for us.”

“We take great pride in partnering with our clients and helping them overcome significant challenges,” said SooYoung S. Lee, PhD, Chief Operating Officer at Goodwin Biotechnology. “Over 23 plus years, we’ve accumulated significant expertise and experience in developing robust processes for manufacturing biopharmaceuticals utilizing cell culture and bioconjugation technologies. Coupled with our expertise in CGMP manufacturing of early- and late-stage clinical trial supplies, we are able to develop solutions for the challenges our clients face by working with our clients, leveraging the skill sets of our scientific staff, and listening to our clients as a team.”