oblimersen and Neutropenia

The BCL-2 family of proteins integrates pro- and anti-apoptotic signals within the cell and is responsible for initiation of caspase-dependent apoptosis. Chronic lymphocytic leukemia (CLL) cells are particularly dependent on the anti-apoptotic protein BCL-2 for their survival, making this an attractive therapeutic target in CLL. Several early efforts to create inhibitors of the anti-apoptotic family members faced significant challenges, but eventually, the BCL-2 specific inhibitor venetoclax moved forward in CLL. Overall and complete response rates to venetoclax monotherapy in relapsed, refractory CLL are approximately 80 and 20%, respectively, even in patients with high-risk 17p deletion. Toxicities have been manageable and include neutropenia, diarrhea, and nausea. The risk of tumor lysis syndrome (TLS), seen in early experience with the drug, has been mitigated by the use of appropriate TLS risk assessment, prophylaxis, and management. Future studies of venetoclax will focus on combination approaches, predictive biomarker discovery, and mechanisms of resistance.

Topics: Aniline Compounds; Antineoplastic Agents; Bridged Bicyclo Compounds, Heterocyclic; Gossypol; Humans; Indoles; Leukemia, Lymphocytic, Chronic, B-Cell; Neutropenia; Proto-Oncogene Proteins c-bcl-2; Pyrroles; Sulfonamides; Thionucleotides

To assess the feasibility and antitumor activity of oblimersen sodium, an antisense oligonucleotide directed to the Bcl-2 mRNA, combined with irinotecan in patients with advanced colorectal carcinoma, characterize the pharmacokinetic behavior of both oblimersen sodium and irinotecan, and examine Bcl-2 protein inhibition in peripheral blood mononuclear cells (PBMC).. Patients were treated with escalating doses of oblimersen sodium administered by continuous intravenous infusion (CIVI) days 1-8, and irinotecan administered intravenously on day 6 once every 3 weeks.. Twenty patients received a total of 84 courses at doses ranging from 3 to 7 mg/kg/day for oblimersen sodium and from 280 to 350 mg/m2 for irinotecan. Febrile neutropenia and diarrhea limited escalation of oblimersen sodium and irinotecan to 5 mg/kg/day and 350 mg/m2, respectively. Other toxicities included nausea, vomiting, fever and fatigue. Steady-state plasma concentrations were achieved within 48 h of beginning oblimersen sodium treatment and the agent was undetectable 24 h after the discontinuation of the infusion. Reduction in levels of Bcl-2 protein in PBMC was documented following treatment with oblimersen sodium. One patient experienced a partial response and 10 additional patients had stable disease lasting 2.5-10 months.. The combination is well tolerated at the recommended phase II oblimersen sodium dose of 7 mg/kg/day CIVI days 1-8 with irinotecan 280 mg/m2 intravenously on day 6 every 3 weeks.

Topics: Adult; Aged; Antineoplastic Agents, Phytogenic; Camptothecin; Colorectal Neoplasms; Dose-Response Relationship, Drug; Drug Combinations; Female; Humans; Irinotecan; Leukocytes, Mononuclear; Lymphopenia; Male; Middle Aged; Neoplasm Metastasis; Neutropenia; Oligonucleotides, Antisense; Thionucleotides