Onconase

Onconase, also known as ranpirnase, is a ribonuclease enzyme derived from the eggs of the northern leopard frog (Rana pipiens). It belongs to the ribonuclease A superfamily and was developed as an anticancer agent because it can degrade cellular RNA and disrupt protein synthesis, leading to tumor cell death. Its proposed selectivity for cancer cells is attributed to differences in cellular uptake and reduced activity of ribonuclease inhibitors in malignant cells, allowing Onconase to evade inactivation.

In laboratory and preclinical studies, ranpirnase showed cytotoxic activity against a range of cancer cell lines. It entered clinical testing in the 1990s and 2000s, including phase I and II trials for malignant mesothelioma and other solid tumors. In mesothelioma, a phase III trial was conducted but failed to meet its primary endpoint, and Onconase did not receive regulatory approval.

The development of Onconase faced corporate and regulatory hurdles; the original developer filed for bankruptcy in the early 2010s, and the rights to the agent were subsequently transferred to a different entity. As of now, Onconase remains an investigational agent with no approved indication, and no active marketing exists in major markets.