Interleukin 1 alpha (IL-1 alpha) is a
cytokine with pleiotropic effects, including cytotoxic-
cytostatic activity against some tumor cell lines. We have conducted a phase I study of recombinant human
IL-1 alpha (rhIL-1 alpha) in 17 patients with refractory
malignancies to examine its toxicity and
biologic activity. rhIL-1 alpha was given as a 2-h IV infusion daily for 5 days at five dose levels (0.08, 0.2, 0.8, 2.0, and 5.0 micrograms/m2). Seventeen patients with
malignancies were treated, with no objective
tumor responses noted. Common toxicities included:
fever (100%), rigors and/or
chills (96%),
myalgia (54%), and
headache (48%). Three patients developed grade III
hypotension. The maximum tolerated dose was 2.0 micrograms/m2. rhIL-1 alpha induced a significant increase in absolute neutrophil count over baseline (p < 0.05), a delayed but significant increase in platelet count over baseline (p < 0.05), and there was a marked increase in the number of progenitors [colony-forming units (CFU)-G, CFU-M, CFU-GM, CFU-GEMM and burst-forming units (BFU-E)] observed in the peripheral blood. Nine of 12 evaluable patients showed an increase in bone marrow cellularity or myeloid:erthyroid ratio. Immunophenotyping did not demonstrate an increase in peripheral blood or bone marrow CD34+ cells.
Interferon-gamma-mediated monocyte cytotoxicity (MCCTX) was significantly enhanced from baseline (p < 0.001), although an increase in direct MCCTX did not reach statistical significance. In summary, rhIL-1 alpha administration is well tolerated at a dose of 2.0 micrograms/m2 with
fever, rigors,
myalgia, and
headache being the most frequent toxicities. Although there were no objective
tumor responses, we have demonstrated significant
biologic activity with increased neutrophil and platelet counts, increased peripheral blood progenitor cells, and enhanced
interferon-gamma-mediated MCCTX.