Drug dependent red cell antibodies and intravascular haemolysis occurring in patients treated with 9 hydroxy-methyl-ellipticinium

Phase II study of elliptinium acetate salvage treatment of advanced breast cancer

Elliptinium acetate (Celiptium) is an intercalating agent belonging to the ellipticine family. This agent has demonstrated clinical activity as salvage treatment in breast cancer using a weekly regimen. However, its clinical use was hampered by important toxicities such as xerostomia and immune-mediated haemolytic reactions due to development of anti-elliptinium IgM antibodies. We have studied 83 patients previously treated for metastatic breast cancer using elliptinium acetate with a different schedule: 80 mg/m2 daily for 3 consecutive days every 21 days. In 80 evaluable patients, an objective response (complete + partial response) was obtained in 5 of 30 patients with visceral metastases (13%), in 6 of 21 patients with soft tissue metastases (29%), and in 3 of 20 patients with mixed metastases (15%). The overall objective response rate was 14/80 (18%, 95% confidence interval = 10-26%). Moderate to severe xerostomia occurred in 10% of patients, while no anti-elliptinium antibodies or haemolytic reactions were detected using this schedule. No significant haematological toxicity, as usually reported with this drug, was observed. Elliptinium acetate has modest but definite activity as salvage treatment of breast cancer. The 3-week schedule seems as active as and less toxic than the weekly schedule.

Hypersensitivity reactions from antineoplastic agents

Antitumor drugs, like any other therapeutic agent, have the ability to incite hypersensitivity reactions. Certain of such drugs (e.g., L-asparaginase and taxol) cause reactions with great enough frequency to be a major impediment to repetitive use of the drug. Very few antitumor drugs have not had at least one reported instance of causing a hypersensitivity reaction. Most reactions are of the type I category in the Gell and Coombs classification, but there also are instances of types II, III, and IV reactions caused by many of the antineoplastic agents. The mechanisms of such reactions have been poorly evaluated in many reports. In analyzing a hypersensitivity reaction in a patient being treated for cancer, one should document that the antitumor drug is indeed the offender, and not an ancillary drug or a formulation product that is being used. There are many tests that evaluate the source and mechanism of hypersensitivity reactions. This article reviews the current information on hypersensitivity reactions to antineoplastic drugs and provides a logical approach for their assessment.

Elliptinium, a DNA intercalating agent with broad antitumor activity in a human tumor cloning system

We have utilized a human tumor cloning system to determine the in vitro antitumor effects of elliptinium, a new DNA intercalating agent. The purpose was to determine which human tumors should be studied in phase II clinical trials with this agent. Eighty-eight out of 282 tumors plated in culture were evaluable for drug-sensitivity assays. The overall in vitro response rate (defined as a less than or equal to 50% survival of tumor colony-forming units compared to control) was 28% at 0.4 micrograms/ml (1/10 of peak plasma level). In vitro activity was noted for elliptinium against breast cancer, renal cell carcinoma, small-cell lung cancer and non small-cell lung cancer. Elliptinium had a higher in vitro activity than adriamycin against this same group of tumors. Six of 25 (24%) adriamycin-resistant tumors were sensitive to elliptimium. Our in vitro response rate in breast cancer correlates with the response rate in phase II clinical trials with this drug. Further phase II clinical trials with elliptinium in patients with renal cell carcinoma, non small-cell lung cancer and small-cell lung cancer are indicated.

Antibody recognition of substituted ammonium ions. Modulation by the counterion

Antibodies directed against elliptinium acetate, a quaternary ammonium compound with antineoplastic activity in man, were obtained in rabbits, after conjugation of the drug with haemocyanin. These antibodies are specific for the quaternary ammonium structure. However, the recognition of the drug can be markedly decreased (ten-fold) by changing the associated counterion. These observations were extended to other ellipticine derivatives that exist in two forms: acetate and chloride. In each case, the recognition of the acetate form was 7-11-fold higher than that of the chloride form. These results could be explained by high-energy strengths existing between the cation and the anion, resulting in a paired-ion antigen. This represents the first identification of antibodies directed to a paired-ion structure, with specificity for both the cation and anion used for immunization. Such results are relevant in the construction of immunoassays for quaternary ammonium compounds.

Polyclonal antibodies to elliptinium acetate: structure-activity relationships and comparison with human anti-elliptinium IgM

In order to elucidate the immune-mediated hemolytic disease induced in man by elliptinium acetate, a quaternary ammonium compound with antineoplastic activity, polyclonal antibodies directed against this hapten were raised in rabbits. The coupling step between drug and carrier was performed according to a putative human in vivo hapten conjugation mechanism. Structure-activity relationships of the resulting IgG were compared with the epitope site recognized by human anti-elliptinium IgM by using a panel of twelve elliptinium acetate analogues. Although both antibodies were directed principally against the quaternary ammonium ion, a poor correlation between the cross-reactivity indices was obtained. In fact, it appeared that both antibodies recognized specifically the ammonium group plus different regions of the molecule: the indole ring for human antibodies, the N-alkyl group and its vicinity for rabbit ones. The specificity of the obtained rabbit polyclonal antisera is discussed, with regard to the conjugation mechanism of the drug occurring in man.

Phase II study of elliptinium in metastatic soft tissue sarcoma

A phase II study was carried out with 9-hydroxy-methyl-elliptinium (9-HME) in metastatic soft tissue sarcoma. The dose was 100 mg/m2 weekly in 1 1/2 hr intravenous infusion protected from light. Nineteen cases were evaluable for response, all previously treated with other chemotherapy regimens. No remissions were seen. Major toxicities were nausea and vomiting, dryness of the mouth and anorexia. It is concluded that 9-HME is not an effective drug in metastatic soft tissue sarcoma.

Phase I study of elliptinium (2-N-methyl-9-hydroxyellipticinium)

Elliptinium (2-N-methyl-9-hydroxyellipticinium), a chemotherapeutic agent whose mechanism of action has not been completely elucidated, intercalates into DNA. In this Phase I clinical trial, the schedule of drug administration consisted of weekly intravenous infusions. Twenty-nine patients were evaluable for toxicity. The initial dose level was 40 mg/m2 and was escalated to 150 mg/m2 through six levels. The dose-limiting side effects were emesis, xerostomia, and azotemia. The lack of myelosuppression was the most striking feature. Objective responses (partial remission, minor response) were seen in one patient each with Hodgkin's disease, non-Hodgkin's lymphoma, breast cancer, and nasopharyngeal carcinoma. We recommend a Phase II evaluation of elliptinium at a dose of 100 mg/m2 on a weekly schedule.

Phase II study of 9-hydroxy-2N-methylellipticinium acetate

A broad phase II trial of elliptinium was conducted in 105 evaluable patients with advanced solid tumors. The drug was given as a 60-90-min i.v. infusion at a weekly dose of 100 mg/m2. Of 36 breast cancer patients, one achieved complete and six achieved partial response for an overall response rate of 19%. Responses lasted for 12-56 weeks from initiation of therapy. There was also one partial response among 21 patients with squamous cell carcinoma of the lung. No response could be obtained in 17 patients with colon cancer, 13 patients with head and neck cancer and 18 patients with a wide variety of other malignancies. Myelosuppression was minimal. Nausea and vomiting were the most frequent toxic effects. The drug also produced serious xerostomia and acute intravascular hemolysis. Asthenia was common. Other adverse reactions included fever and chills, transient neurologic and cardiovascular manifestations and renal function impairment. Additional work is needed to define optimal modes of drug administration.

Phase I clinical study of 9-hydroxy-2N-methyl-ellipticinium acetate (NSC-264137) administered on a 5-day i.v. schedule

Twenty-three patients with advanced solid tumors received 9-hydroxy-2N-methyl-ellipticinium acetate at a single daily i.v. dose of 15-80 mg/m2 for 5 consecutive days, repeated every 3 weeks. One partial and one minor response were achieved in two patients with breast cancer. Dryness of the mouth was dose-related and dose-limiting. Local phlebitis was also dose-related and frequently severe at the highest dose levels. Other non-hematologic toxic effects were essentially mild to moderate and included nausea, vomiting, diarrhea, stomatitis, fever, weakness, transient renal and hepatic impairment, alopecia and chest pain. Minimal myelosuppression was encountered. It appears that 60 mg/m2/day is the maximum tolerated dose with a five-day schedule. According to our findings, this schedule does not seem to offer any advantage over the previously tested weekly administrations.