BiVictriX Therapeutics plc has announced positive in vivo data from a toxicity evaluation study with BVX001, the company’s lead program, compared to gemtuzumab ozogamicin (GO). \n\n\n\nGO, marketed as Mylotarg, is the only approved antibody drug conjugate (ADC) indicated for the treatment of acute myeloid leukemia (AML). One of the significant toxicities of GO is the reduction in normal neutrophil counts in patients with AML. \n\n\n\nNeutrophils are a form of immune cell and a reduction in the number of these cells heightens the risk of developing potential fatal severe infections and sepsis, a major concern in patients with AML.\n\n\n\nBiVictriX' lead candidate study results\n\n\n\nBVX001 was reported to be well-tolerated and showed a highly favorable safety profile across two doses of BVX001 (0.3 mg/kg and 3 mg/kg), compared with the reported maximum tolerated dose of GO (0.3 mg/kg) in a CD34-boosted humanized murine model. \n\n\n\nThe results showed that the proportion of healthy human CD33 myeloid cells in the bone marrow was significantly lower with GO compared to BVX001 at both an equivalent dose to GO (0.3mg/kg) and a 10-fold higher dose (3mg/kg), at seven- and 14-days post-injection.\n\n\n\nThe total number of healthy neutrophils and total healthy leukocytes, types of specialized immune cells, were significantly lower with GO compared to the equivalent dose of BVX001, at fourteen days post-injection.\n\n\n\nThe total number of healthy human CD33 cells was significantly lower with GO compared to the vehicle control seven days post-injection.\n\n\n\nThese results model commonly reported toxicities of GO in clinical practice.\n\n\n\nOther observed effects with GO included a non-statistical lower level of healthy early bone marrow progenitor cells at day 14 post injection, compared to both doses of BVX001. A non-statistical higher proportion of CD7 cells among CD3 T cells in blood at day three post injection was reported with GO, compared to BVX001 and the control vehicle.\n\n\n\n'Game-changing treatment'\n\n\n\nTiffany Thorn, chief executive officer of BiVictriX Therapeutics plc, said: “Receiving these positive preclinical safety results, soon after identifying a development lead for BVX001, reinforces the superior cancer selectivity of our Bi-Cygni approach – designing drugs with reduced toxicity on normal cells. \n\n\n\n“These findings move us another step closer to the clinic and provide further evidence that our first-in-class platform offers the potential to deliver the next generation of highly selective, anti-cancer therapies. Generating data that demonstrates BVX001 was well-tolerated in this in vivo model and showed reduced off-target effects, when compared to the only approved ADC drug addressing AML, puts us in a strong position to break into the market with the goal to offer a novel, game-changing bispecific treatment with better efficacy and improved safety for patients.”\n\n\n\nBiVictriX Therapeutics is now focused on delivering additional in vivo efficacy data to further strengthen the preclinical data package for BVX001, as it looks to progress this molecule towards the clinic.