Chlorambucil central nervous toxicity: a significant side effect of chlorambucil therapy in childhood nephrotic syndrome

Potent Chlorambucil-Platinum(IV) Prodrugs

The DNA-alkylating derivative chlorambucil was coordinated in the axial position to atypical cytotoxic, heterocyclic, and non-DNA coordinating platinum(IV) complexes of type, [Pt^IV(H_L)(A_L)(OH)₂](NO₃)₂ (where H_L is 1,10-phenanthroline, 5-methyl-1,10-phenanthroline or 5,6-dimethyl-1,10-phenanthroline, A_L is 1S,2S-diaminocyclohexane). The resultant platinum(IV)-chlorambucil prodrugs, PCLB, 5CLB, and 56CLB, were characterized using high-performance liquid chromatography, nuclear magnetic resonance, ultraviolet-visible, circular dichroism spectroscopy, and electrospray ionization mass spectrometry. The prodrugs displayed remarkable antitumor potential across multiple human cancer cell lines compared to chlorambucil, cisplatin, oxaliplatin, and carboplatin, as well as their platinum(II) precursors, PHENSS, 5MESS, and 56MESS. Notably, 56CLB was exceptionally potent in HT29 colon, Du145 prostate, MCF10A breast, MIA pancreas, H460 lung, A2780, and ADDP ovarian cell lines, with GI₅₀ values ranging between 2.7 and 21 nM. Moreover, significant production of reactive oxygen species was detected in HT29 cells after treatment with PCLB, 5CLB, and 56CLB up to 72 h compared to chlorambucil and the platinum(II) and (IV) precursors.

Properties of several glycidyl methacrylate-triallyl isocyanurate based affinity adsorbents for removing circulating immune complexes

Biocompatible affinity adsorbents prepared from macroporous glycidyl methacrylate-triallyl isocyanurate copolymer (GT) has been used for removing circulating immune complexes (CICs). In this work, adsorption of circulating immune complexes on GT-based affinity adsorbents has been studied by using batch and hemoperfusion studies. In batch mode, the equilibrium adsorption level was determined to be a function of the contact time, temperature, initial CIC concentration and adsorbent dosage. In animal hemoperfusion trials, removal of CICs is efficient and rapid. IgG, IgM and complement C3, C4 are minimally affected. There are negligible decreases in RBC, WBC, PLT and HB. Acid-base equilibrium, electrolytes and plasma proteins also are minimally affected.

Chlorambucil-induced myoclonus in a cat with lymphoma

Chlorambucil is an alkylating agent commonly used in veterinary oncology for conditions including lymphoma. Chlorambucil neurotoxicity has been well recognized in human patients. Onsets of central nervous system signs, such as myoclonus, tremors, muscular twitching, agitation, and tonic-clonic seizures, have been reported in humans and laboratory animals treated with chlorambucil. This case of a cat with intestinal lymphoma represents the first veterinary patient reported to have chlorambucil-induced neurotoxicity. Neurotoxicity should be considered a potential side effect of chlorambucil therapy in veterinary patients.

Chlorambucil-induced seizures

BACKGROUND

Anecdotal reports of chlorambucil-induced seizures have sporadically appeared, mainly in the nononcologic literature. The majority of cases have occurred in patients treated with high dose therapy and in children with nephrotic syndrome. Because of its rarity, oncologists and hematologists may not be aware of this potential complication.

METHODS

Two elderly patients with a remote history of seizures had generalized tonic-clonic seizures 3 days after chlorambucil therapy was initiated. A MEDLINE search was performed of previously reported cases and additional cases were found in the bibliographies of retrieved articles.

RESULTS

In addition to the 2 new cases presented here, there have been 28 reported cases of chlorambucil-induced seizures. Underlying diseases included nephrotic syndrome (n = 12 cases), solid tumors (n - 10 cases), non-Hodgkin's lymphoma (n = 3 cases), and chronic lymphocytic leukemia (n = 1 case). Five cases were secondary to accidental overdose. Sixteen of 30 patients were younger than 18 years; 11 had nephrotic syndrome, 1 had choriocarcinoma, and 4 accidentally ingested the medication. Nine of 14 adults received high dose chlorambucil in Phase I-II studies or as part of a conditioning regimen prior to bone marrow transplantation for solid tumors, 3 were on intermittent pulse therapy, 1 was on daily low dose administration of chlorambucil, and 1 patient had an accidental poisoning. Two patients had recurrent seizures when they were rechallenged with chlorambucil.

CONCLUSIONS

A relatively high incidence of chlorambucil-induced seizures in children with nephrotic syndrome may be due to an increased sensitivity in childhood or altered pharmacokinetics. In adults without a seizure history, seizures were observed only in patients treated with high dose chlorambucil; however, in adults with a seizure history, lower doses as used in pulse therapy also caused seizures. In the latter group of patients, daily low dose chlorambucil or, more likely, an alternative drug may be the safest approach to therapy.

Myoclonus due to chlorambucil in two adults with lymphoma

OBJECTIVE

To report myoclonus due to chlorambucil therapy in two adults with lymphoma, and to review the literature of chlorambucil neurotoxicity in adults.

CASE SUMMARIES

Case 1: An 81-year-old man with lymphoma being treated with chlorambucil developed jerking movements and stiffness that persisted for 3 days and intensified at night. The dosage of chlorambucil was decreased with a subsequent decrease in symptomatology. Resolution of the myoclonus occurred with discontinuation of the chlorambucil. Rechallenge evoked a return of tremors the next day that later became constant and again resolved on discontinuation of chlorambucil. Case 2: A 75-year-old woman with lymphoma being treated with chlorambucil developed jerking movements in her limbs, particularly in her arms and right hip. The symptoms were so severe they prevented the patient from leaving her house. All symptoms resolved within 2-3 days after the cycle was completed and did not return. She was diagnosed as having had chlorambucil-induced myoclonus.

DATA SOURCES

Searches were performed on MEDLINE, CancerLit, and Science Citation Index Review to identify reports and articles discussing chlorambucil-induced neurotoxicity, particularly myoclonus.

DISCUSSION

Chlorambucil-induced myoclonus has been described in overdose situations and in the treatment of nephrotic syndrome in children. Three cases of reversible myoclonic activity associated with high-dose chlorambucil in adults have also been described. In each case, the myoclonus resolved following discontinuation of the drug. Only one other conclusive case of low-dose chlorambucil-induced myoclonus in an adult has been described. The two cases presented here are unique in that the myoclonus occurred in adults receiving low-dose chlorambucil who had no myoclonus before or after treatment with the drug.

CONCLUSIONS

From the cases reviewed, it appears that chlorambucil may induce myoclonus in adults receiving therapeutic dosages of chlorambucil. The neurologic status of patients receiving chlorambucil should be followed closely during treatment. If myoclonus develops, drug-induced myoclonus should be considered, as well as discontinuation of the drug.