Background: Cognate immunity against neoplastic cells depends on a balance between effector T cells and regulatory T (Treg) cells. Treg cells prevent immune attack against normal and neoplastic cells by directly suppressing the activation of effector CD4 + and CD8 + T cells. We postulated that a recombinant interleukin 2/diphtheria toxin conjugate (DAB/IL2; Denileukin Diftitox; Ontak) may serve as a useful strategy to deplete Treg cells and break tolerance against neoplastic tumors in humans.
The combination of temozolomide and thalidomide is well tolerated in patients with very advanced heavily pretreated metastatic melanoma. It has modest activity in this population with grave prognosis.
13098 Background: AS1411 is an oligonucleotide aptamer that binds to nucleolin, a protein expressed on the surface of tumor cells. A dose-escalating phase I trial in patients with various advanced cancers revealed no serious toxicities and consequently did not reach an MTD. There was evidence of activity, especially in renal cell carcinoma (RCC). This study has been reopened for further dose escalation to reach an optimal biological dose (OBD; unless an MTD is reached) in patients with RCC and non-small cell lung cancer (NSCLC). Methods: Patients had advanced RCC or NSCLC refractory to standard treatment. AS1411 was administered as a single continuous 7-day iv infusion, with the option of a second cycle. Patients were enrolled in cohorts of 3. If no serious toxicity was observed within 28 days, the dose was escalated to the next level. Toxicity was graded using the NCI CTCAE v3.0. The study plan was to enroll additional patients at the OBD such that a total of 12 RCC and 12 NSCLC patients received a 7-day infusion. Blood and urine samples were taken for pharmacokinetic analysis. Tumor responses were assessed every 28 days using the RECIST guidelines. Results: No serious adverse events have been observed up to a dose of 22mg/kg/day, which was associated with a mean peak plasma concentration of 1.5 μM. Response findings to date are as follows: of 5 RCC patients, 1 maintains a near-complete response 18 months after treatment, 3 have ongoing stable disease (SD; 1 at 3 months, 2 at 2 months) and a fourth had progressive disease (PD) at 2 months post-treatment; of 3 NSCLC patients, 1 has an ongoing SD and 2 had PDs at 1 month post-treatment. Recruitment and follow up continues. Conclusions: A 7-day infusion of AS1411 at 22mg/kg/day was not associated with any serious adverse events and achieved peak plasma concentrations in the range at which killing of various cancer cell lines is observed in vitro. A single further escalation is planned to reach a dose of 40mg/kg/day. Observation of additional cases of stable disease in RCC supports the previous observations of anti-cancer effects in this disease. [Table: see text]
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