A Phase I/IIa Trial of HMBD-001 in Advanced HER3 Positive Solid Tumours

HMBD-001 is a type of drug called a monoclonal antibody. It works by targeting a protein called HER3, which is found in high numbers in some types of cancers including those that contain fusions in a gene called NRG1. By attaching itself to this protein, it may then work to kill the cancer cells or to stop them growing. This is a first-in-human clinical trial that has two parts: Part A is a 'dose escalation' phase where small groups of participants will receive increasing doses of HMBD-001 on its own (as a single agent) to find the safest dose that best targets cancer cells. Part B is a 'dose expansion' phase where larger groups of participants with specific cancer types that are known to have high levels of the protein HER3 or that have a confirmed NRG1 gene fusion will receive the highest doses of HMBD-001 considered to be safe as monotherapy from Part A in combination with other anti-cancer drugs that are already licensed for use. In Part B Arm 1, participants will receive HMBD-001 in combination with enzalutamide. Enzalutamide is a drug used to treat prostate cancer. Prostate cancer is known to be sensitive to androgens (hormones associated with male characteristics), and enzalutamide blocks the action of androgens by limiting the binding of androgens to androgen receptors. This slows the growth of prostate cancer cells and may kill them. The main aims of the clinical trial are to find out: * The best dose of HMBD-001 alone and in combination with other anti-cancer drugs that should be given to participants. * More about the potential side effects of HMBD-001 when given alone and in combination with other anti-cancer agents, and how they can be managed. * What happens to HMBD-001 inside the body and how it affects cancer cells. * The potential anti-tumour activity of HMBD-001 as a single agent and in combination with other anti-cancer agents in specific tumour types of HER3-expressing tumours or tumours with NRG1 gene fusions.