Patrys Limited announced new data from a successful preclinical study highlighting the potential for using its deoxymab antibodies as targeting agents in antibody drug conjugates (ADCs). This promising approach may open up a range of new potential development and partnering opportunities for the company. Antibody drug conjugates (ADCs) harness the targeting attributes of antibodies to deliver payloads (usually small molecule therapeutics) specifically to the sites of disease and are one of the most active areas of drug development. The company now confirms that it has been able to conjugate an anticancer drug called monomethyl auristatin E (MMAE) to its full-sized IgG deoxymab, PAT-DX3. MMAE is a highly potent anti-cancer compound which, due to its extreme toxicity, can only be used when conjugated to an antibody for targeted delivery. MMAE has been used in several ADC's, some of which are approved or in late-stage clinical development, and consequently provided an ideal therapeutic payload to establish if Patrys' deoxymab antibodies could be used as targeting agents for ADCs. MMAE conjugated to PAT-DX3 (PAT-DX3-MMAE) was administered to mice (6 mice per group) implanted with xenografts of the human breast cancer cell line MCF7 and significantly inhibited tumour growth by 95% at day 31 (p < 0.01). On day 21 of the study, when the last of the four doses of PAT-DX3-MMAE was administered (indicated by arrows), tumour growth inhibition was 99.7% (p < 0.01). This latest preclinical study was conducted to determine if this activity would allow Patrys' deoxymabs to be used as a targeting agent for ADCs directed against solid tumours. By using a well-established and validated therapeutic ADC payload, the anticancer drug MMAE, Patrys has shown deoxymabs can be used to target delivery to tumours in animals. This approach could form the basis of new ADCs that may have clinical utility for a broader range of cancer applications but additional studies will need to be performed to better understand the potential for on and off target toxicity using this approach. Furthermore, as deoxymabs are able to transit the blood-brain barrier, it also opens up the possibility of developing ADCs that could be used to treat primary and secondary cancers in the brain.