Therapy of small cell carcinoma of the lung with hexamethylmelamine

Hexamethylmelamine: A Review

A review of the investigational oncolytic agent hexamethylmelamine (HMM) is presented. HMM probably acts as an antimetabolite. The value of HMM lies in its relatively mild hematologic toxicity, its ability to increase response and survival rates in combination, and in its response in patients refractory to standard chemotherapy. The greatest response is in advanced ovarian cancer: Alone (overall response, 28–42 percent) and in combination with cyclophosphamide, mediotrexate, and 5-fluorouracil (overall response, 76–79 percent). Lung cancer has shown response to HMM, with best activity exhibited in small cell carcinoma (20–28 percent). HMM alone has demonstrated activity (overall response, 39 percent) in Hodgkin's and non-Hodgkin's lymphomas, a rate equal to that of bleomycin, and without cross resistance to this agent. Its value in breast cancer is questionable. The average tolerated dose is 8 mg/kg/d. Major dose-limiting toxicities are gastrointestinal, although hematopoietic depression, peripheral neuropathies, and central nervous system disorders also occur. Pentamethylmelamine, a water soluble metabolite, is die potentially marketable form of the drug.

Altretamine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in cancer chemotherapy

Altretamine (hexamethylmelamine) is a cytotoxic antineoplastic agent which appears to require metabolic activation. Metabolic intermediates may act as alkylating agents; however, altretamine is not directly cross-resistant with classical alkylating agents. Objective response rates to orally administered altretamine as salvage therapy in patients with advanced ovarian cancer were 0 to 33%, with disease stabilisation in a further 8 to 78% of patients. Response rates appear to be higher in patients who have responded to previous alkylating agent or cisplatin-based therapy. There is some evidence that addition of altretamine to platinum-based combination regimens used for induction therapy of advanced ovarian cancer may improve long term survival, particularly in patients with limited residual disease. Although altretamine displays some activity in small cell lung cancer, it is unlikely to have any clinical role in the management of non-ovarian cancer. Altretamine appears to be relatively well tolerated, with gastrointestinal, neurological and haematological toxicities being the main dose-limiting adverse effects. However, assessment of accurate incidence rates for these effects is complicated by the use of altretamine with cisplatin. On the basis of the emerging body of clinical evidence, altretamine appears to have a limited role in the treatment of persistent or recurrent advanced ovarian cancer, primarily in patients who are potentially platinum sensitive yet intolerant of platinum analogues. Additionally, altretamine may be added to platinum-based regimens for induction therapy of advanced ovarian cancer. At the doses currently recommended, altretamine offers a reasonably well tolerated regimen that can be administered orally and is suitable for use on an outpatient basis.

New frontiers in the treatment of lung cancer

Surgical resection still is the only significant curative approach in nonsmall cell lung cancer. Recent surgical experience indicates that a modest decrease in the death rate from bronchogenic carcinoma may occur in three general areas: (1) the detection and treatment of radiographically occult squamous cell carcinoma; (2) the combination of adjuvant chemotherapy and surgical excision in selected patients with small cell carcinoma; and (3) surgical resection and postop irradiation of patients with hilar and mediastinal lymph node metastases. At the time of diagnosis, 80 to 85% of the patients present with unresectable lung cancer. These patients may benefit from other modalities of therapy, i.e., radiotherapy, chemotherapy, or immunotherapy. Failures following radiotherapy in unresectable nonsmall cell lung cancer are due to (1) distant metastasis, (2) local region failure, and (3) local and distant failure. To increase the local control, new methods of treatment have been tried, such as hyperfractionation of radiotherapy and the use of 131I antiferritin immunoglobulin. The development of effective systemic chemotherapy is necessary to treat metastatic bronchogenic carcinoma. The response rate to chemotherapeutic agents is substantially lower in nonsmall cell carcinoma than in small cell carcinoma. Investigation is ongoing to assess the effectiveness of new antitumor drugs used alone, in combination with other drugs, or combined with other modalities for the treatment of bronchogenic carcinoma.