Karen H. Moore

Phase 1 Clinical Trial of Recombinant Interleukin-2: A Comparison of Bolus and Continuous Intravenous Infusion

The toxicologic, biologic, and clinical effects of recombinant interleukin-2 (IL-2) were tested in 25 patients with cancer. Escalating doses from 10(3) to 10(7) U/m2 per day were given by either daily bolus injection (BI) or continuous infusion (CI) for 7 consecutive days. Dose-limiting toxicities included a decline in performance status, systolic hypotension, and fever, which reversed promptly with discontinuation of therapy. The maximum tolerated dose of IL-2 by BI for 7 days was 3 X 10(6) U/m2 per day and for CI was 10(6) U/m2 per day. Significant changes in the number, phenotype, and function of circulating peripheral blood lymphocytes occurred at doses greater than or equal to 10(6) U/m2 per day by both administration schedules. With the initiation of therapy, a decline in the number of circulating peripheral blood lymphocytes (PBL) was seen in patients treated by either BI or CI. Additionally, the in vitro cytotoxic activity of these PBL against K562 was markedly decreased. Within 24 h of completing BI or CI, a rebound increase in the number of circulating PBL was seen. The phenotype of the circulating PBL after completion of treatment showed a significant (p greater than or equal to 0.05) increase in the numbers of OKT-3+, OKT-8+, OKT-10+, OK-Ia+, OKM1+, and OKT-11+ for patients treated by CI. Those patients treated by BI had a significant increase in Ia+ and OKT10+ cells. At IL-2 doses greater than or equal to 10(5) U/m2 per day, the PBL obtained following treatment with rIL-2 demonstrated in vitro cytotoxic capacity against K562 target cells that was significantly enhanced over pretreatment levels. This study demonstrates that IL-2 can be given by CI or BI in a non-ICU setting with acceptable dose-dependent toxicity. Upon completion of treatment an increase in the number of activated cells could be detected. Although no clinical responses occurred, the generation of endogenous activated PBL capable of enhanced cytotoxicity is encouraging. Future studies will explore the use of multiple courses of treatment with IL-2 to determine if therapeutic efficacy can be accomplished.

the influence of autologous lymphokine‐activated killer cell infusions on the toxicity and antitumor effect of repetitive cycles of interleukin‐2

Twenty patients with refractory malignancies were treated with a protocol evaluating the addition of ex vivo‐activated autologous lymphokine‐activated killer (LAK) cells to a clinically tolerable interleukin‐2 (IL‐2) regimen (four weekly cycles of human recombinant IL‐2 at 3 × 106 U/m2/day by continuous infusion for 4 days/week). Sixteen patients completed their induction month of therapy, two had a partial response, six had stable disease, and eight had progressive disease. Four patients had clinical toxicity preventing completion of the induction month of therapy, and one of these patients died during therapy. Significant clinical toxities included decreased performance status, weight gain, catheter‐related thromboses, infectious complications, fever, hypotension, and dyspnea or hypoxemia requiring oxygen. Thus, the addition of LAK cell infusions to this IL‐2 regimen did not cause a noticeable change in antitumor response rate but did cause more severe toxicity.

Prolonged Interleukin-2 (IL-2) Treatment Can Augment Immune Activation Without Enhancing Antitumor Activity in Renal Cell Carcinom

Preliminary studies involving small numbers of patients have suggested that interleukin-2 (IL-2) administered by continuous infusion in repetitive weekly cycles using doses of 3 x 10(6) U/M2/day is immunologically active and can induce tumor responses in patients with renal cell carcinoma. This study was designed to examine both the immunological and clinical effects of prolonged infusion IL-2 given by repetitive weekly cycles; first at moderate doses for 4 weeks as an impatient followed by lower doses of IL-2 for up to 5 months. Prolonged IL-2 treatment was investigated because previous studies revealed that patients had a return to their baseline immune status within 4 weeks after completing IL-2 treatment. Twenty-five patients (including 18 with renal cell carcinoma) were treated with one of two regimens utilizing IL-2 as sole therapy. These regimens were designed to induce augmented and prolonged immune activation based upon in vitro and in vivo data. Though patients on both arms of the study demonstrated sustained lymphocytosis, increase in numbers of natural killer cells, and induction of lymphokine-activated killer activity with prolonged IL-2 administration, only 1 out of the 18 patients with renal cell carcinoma demonstrated a sustained partial antitumor response to therapy. Furthermore, several patients demonstrated profound immune activation, without any evidence of tumor regression. The lack of clinical responses in these patients showing marked activation of LAK cytotoxicity suggests that other variables must also influence the likelihood of antitumor effects for patients receiving IL-2 therapy.

A pilot phase II trial of continuous-infusion interleukin-2 followed by lymphokine-activated killer cell therapy and bolus-infusion interleukin-2 in renal cancer.

Nine patients with metastatic renal cell carcinoma were entered into a pilot protocol including a 4-week regimen utilizing human recombinant interleukin-2 (IL-2) and in vitro lymphokine-activated killer (LAK) cells. The regimen included 2 weeks (4 days of treatment and 3 days of rest/week) of continuous-infusion (c.i.) IL-2 at 3 x 10(6) U/m2/day, followed by two leukaphereses. LAK cells were cultured in vitro for 48 to 72 h and administered as a single infusion, followed by 9 days of bolus i.v. injections of 10(6) U IL-2/m2/dose, given every 8 hours (t.i.d.). The average (+/- SD) number of LAK cells infused per patient was 7.2 x 10(10) (+/- 3.5 x 10(10)). One patient showed > 50% shrinkage of tumor (lung + renal bed recurrence). Toxicity was similar to that encountered in other studies using similar IL-2 doses and LAK cells and consisted of fever, hypotension, fluid retention, and reversible renal insufficiency. These results indicate that the 2 weeks of IL-2 c.i. provided conditions enabling the harvest of large quantities of mononuclear cells from the peripheral blood of patients; this could be useful for future trials requiring the use of in vitro activated lymphocytes. Nevertheless, these pilot data suggest that this regimen of prolonged t.i.d. IL-2 administration after the LAK infusion does not seem to generate any improvement in antitumor effects from those obtained using other LAK + IL-2 regimens.

In Vivo Effects of Multiple Cycles of Recombinant Interleukin-2 (IL2) on Peripheral Granulocyte-macrophage Hematopoietic Progenitors Circulating in the Blood of Cancer Patients

The numbers of peripheral blood (PB) granulocyte-macrophage colony forming units (CFU-GM) were evaluated in five patients treated with multiple weekly cycles of recombinant interleukin-2 (IL2). A 4.5-12 fold increase in the number of CFU-GM was evident within 8 days after the beginning of the treatment. The maximal increase in the absolute numbers of CFU-GM/ml blood caused by the IL2 treatment, ranged from 14 to 57 times the baseline values and was reached after two or three cycles of IL2. IL2-activated PBMC, added in vitro to the PBMC of a normal donor did not modify the number of CFU-GM present in the donor PBMC. CFU-GM were also recovered from frozen samples of in vivo IL2-activated PBMC.