Iron-based injection shows early activity in 19 cancer patients

Sixteen of 19 patients. That is how many saw their disease held in check after physicians injected an iron-based compound directly into tumors that had kept growing despite earlier treatment. The result comes from a Phase I study published on October 1 in Signal Transduction and Targeted Therapy, carried out at three hospitals in the Chinese provinces of Sichuan, Hubei and Shandong.

The idea starts far from oncology. Industrial wastewater is cleaned by a reaction in which iron meets hydrogen peroxide and produces hydroxyl radicals, highly reactive molecules that break down organic pollutants. The team, led by Professor Wang Yongsheng at West China Hospital, adapted that principle to cancer. They combined a clinically approved nanocrystalline carbon injection with ferrous sulfate to make a formulation called CNSI-Fe. It is designed to induce ferroptosis, a form of cell death driven by iron-dependent damage to cell membranes. Normal cells have antioxidant defenses, including glutathione, that help protect against this damage. Before reaching patients, CNSI-Fe had inhibited tumor growth in six tumor models in animals, including colorectal, breast and pancreatic cancer.

The 19 participants had sarcoma, head and neck, pancreatic, non-small-cell lung, ovarian, breast or vulvar cancer, and 16 had stage IV metastatic disease. Every one had received at least two previous lines of systemic therapy. The 84.2 percent disease control rate counts both stable disease and tumor shrinkage; the objective response rate, which measures shrinkage alone, was 10.5 percent. Two patients had tumors that shrank. Injected lesions responded better than the overall set of lesions tracked across the body. Injection pain was the most common adverse reaction, affecting 89.5 percent of participants, followed by hypertension in 52.6 percent. One patient withdrew because of a hypersensitivity reaction. The researchers reported no severe hematological toxicity and no liver or kidney toxicity.

The limits are plain. The study was small and single-arm, with no comparison group, so it cannot establish how well the treatment works. Wang himself said the approach "requires further evaluation through randomized Phase II/III trials." For patients with refractory solid tumors, the next question is whether this early activity turns into a reliable benefit. A Phase II trial involving 52 patients across 10 Chinese hospitals is now underway to answer part of that, but the sources give no timeline for its results or for any approval.