Ken Iwai

Effect of arterial administration of high-molecular-weight anticancer agent SMANCS with lipid lymphographic agent on hepatoma: a preliminary report.

A clinical evaluation of arterial infusion of high-molecular-weight antitumor agent SMANCS dissolved in lipid lymphographic agent (thiodol) in 44 patients with mostly unresectable hepatoma is described. The treatment regimen demonstrated significant merits both therapeutically and diagnostically. Marked antitumor effects were shown in the decreased serum alpha-fetoprotein levels (86% of cases) and tumor size (95% of cases), and in survival period and histological findings. Furthermore, there was increased diagnostic sensitivity using CT scan, plain X-rays or ultrasound. The procedure of selective arterial administration of 3-4 mg of SMANCS in 3-4 ml of ethiodol per dose was simple to perform and was required only once every 3-4 weeks. Both ethiodol and the drug accumulated more selectively in tumor than in any other tissues and their activity remained for more than 3 weeks. Only minimal side-effects were associated with SMANCS and ethiodol during this study.

Selective targeting of anti-cancer drug and simultaneous image enhancement in solid tumors by arterially administered lipid contrast medium

Twenty‐four patients with various solid tumors including metastatic liver cancer and cancer of the lung, gallbladder, and pancreas were treated with a lipophilic macromolecular drug, copoly(styrene‐maleic acid) conjugated neocarzinostatin (SMANCS). The drug was dissolved in a lipid contrast medium Lipiodol and administered by catheterizing the respective feeding arteries under x‐ray monitoring. The advantages of this therapy include: (1) selective deposition of Lipiodol with the anti‐cancer drug in the target tumor, (2) a pronounced and long‐lasting anti‐cancer effect, (3) enhanced visulization of the tumor on x‐ray examinations for a prolonged period which also facilitated the long‐term follow‐up, (4) semiquantitative evaluation of the dosage regimen by x‐ray examination before further administration, (5) general applicability due to procedural simplicity, and (6) little side effect. Since the amount of Lipiodol and SMANCS used per administration for a patient (1.0–5.0 ml; 1.0–5.0 mg) was far less that the anticipated toxicity (LD50 of Lipiodol = 95 ml/60 kg, dog, intravenously; and that of SMANCS = 3.4 mg/kg, mouse, IV), no deleterious effects to such critical organs as the brain, heart, lung, liver, or kidneys were observed upon radiologic and general clinical examination.

Tailor-making of protein drugs by polymer conjugation for tumor targeting: A brief review on smancs

Chemical conjugation of poly(styrene-co-maleic acid) to an antitumor protein (neocarzinostatin) yielded an entirely new derivative designated as smancs (polystyrene-maleic acid conjugated neocarzinostatin). The purpose of the modification was to improve its pharmacological properties; the resulting conjugate exhibited much higher tumoritropism and lymphotropism, enhancedin vivo stability (about ten times), higher chemotherapeutic index (lower toxicity), and decreased antigenicity. Another advantage associated with this molecular engineering was an increased hydrophobicity. By this character it was solubilized in lipid contrast medium LipiodolR, which facilitated highly sensitive detection under x-ray-accompanying selective anticancer effectin situ. Three factors were responsible for such improvements: molecular size, hydrophobicity, and polyanionic nature. Most of the known drugs so far used as therapeutic agents are less than 1000 daltons, and those with larger molecular weights have been explored much less extensively. By polymer conjugation, the size of the drug can be extended to about 15,000 daltons (macromolecular therapeutics). The most outstanding characteristic of smancs (16,000 daltons) was the tumoritropicity, which may be a result of the highly developed neovasculature of solid tumors. Smancs as a prototype drug thus appears to lead the way in cancer drug targeting.