A phase I study of nelfinavir, an FDA approved HIV protease inhibitor, in adults with refractory solid tumors

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Background: Preclinical studies show that HIV protease inhibitors such as nelfinavir (N) have dose- dependent, pleiotropic anti-cancer activities. However, the maximum tolerated dose (MTD) of N has not been established in humans. Methods: Pts were treated on a modified Fibonacci dose-escalation scheme with a twice daily oral dose of N starting at the FDA approved dose of 1250 mg bid on a 21-day cycle. Patients with refractory solid tumors, ECOG PS < 2, and adequate organ function were eligible. Therapy continued until MTD or disease progression. PBMCs as well as optional tumor biopsies were collected for Akt inhibition and expression of markers of ER stress (ERS). Results: 14 patients have been enrolled. Of the 11 evaluable for toxicity, there were 10 men, 10 Caucasians, and 1 African American (median age 63 years (range 24 - 77)). Tumor types included NSCLC (3), SCLC (2), thyroid (3), pancreatic (1), colorectal (1), and renal cell (1). Median number of prior systemic therapies was 2 (range, 1 - 6). There have been no grade 4 or 5 toxicities. We observed 12 grade 3 toxicities that were asymptomatic laboratory abnormalities. The most prevalent toxicities were ALT transaminitis (5 events in 8 subjects in dose level ((DL) 2, 3, 4), AST transaminitis (4 events in 8 subjects in DL 2, 4), diarrhea (8 events in 5 subjects in DL 2, 3, 4), and hyperglycemia (5 events in 5 subjects in DL 1, 2, 3). Enrollment continues at DL 4 (3125 mg twice daily). There have been no responses. Two subjects with lung cancer had stable disease for 9 weeks. Pharmacokinetic data revealed median Cmax of 2,461.5 ng/ml (DL1), 11,809 ng/ml (DL2), 11,576 ng/ml (DL3), and 11,986 ng/ml (DL4), occurring 4 hours after an oral dose. There was no relationship between the drug levels and albumin levels. Akt inhibition and increased expression of markers of ERS and apoptosis have been observed in PBMCs from week 1 in the majority of patients at every dose level, but there was no correlation with clinical response. Conclusions: N appears to be well tolerated in subjects with advanced solid tumors at 2.5 times the FDA approved dose. AUC data suggest that there may be only minimal increases in plasma drug concentrations with doses above 1875 mg twice daily.

No significant financial relationships to disclose.

Effects of crystalloid solutions on circulating lactate concentrations: Part 1. Implications for the proper handling of blood specimens obtained from critically ill patients

OBJECTIVES

a) To test the hypothesis that circulating lactate concentrations are the same in simultaneously collected arterial and central venous blood specimens; b) to test the hypothesis that even small amounts of crystalloid solutions, which are inadequately "cleared" from these indwelling arterial and venous catheters, can lead to clinically important and misleading changes in the measured lactate values.

DESIGN

A prospective, multiexperiment study.

SETTING

A critical care research laboratory and a 20-bed intensive care unit (ICU).

PATIENTS

Three hundred fifty-five patients.

INTERVENTIONS

Blood samples were collected.

MEASUREMENTS AND MAIN RESULTS

Experiment 1: Simultaneously collected arterial and central venous blood specimens were obtained on 148 occasions from 48 medical ICU patients receiving no lactated Ringer's solution (RL). Arterial and central venous lactate values were nearly identical in these patients. The correlation between the arterial and central venous lactate concentrations was excellent (r2 = .85; p < .0001) and the agreement between the arterial and central venous lactate concentrations was also excellent (bias and precision = 0.04 mmol/L and +/- 0.38 mmol/L, respectively). Experiment 2: Arterial and mixed venous blood samples were obtained from 100 percutaneous transluminal coronary angioplasty (PTCA) and 75 cardiac surgical patients immediately before the performance of these cardiac procedures. We found the central venous lactate concentrations to be higher than arterial lactate values in the cardiac surgical group, and there was a very poor correlation (r2 = .07) between arterial and central venous lactate values in the cardiac surgical group. The correlation between central venous and arterial lactate concentrations in the PTCA patients was excellent (r2 = .84) and similar to the findings of experiment 1. Since the cardiac surgical patients received RL and the PTCA patients received no RL, we speculated that the intravenous infusion of RL in the cardiac surgical group accounted for these discordant findings. To test this speculation, we performed experiments 3 and 4. Experiment 3: In a large bench study, blood specimens were divided into multiple 1-mL aliquot portions, to which 0.01, 0.05, 0.10, 0.50, or 1.0 mL of various crystalloid solutions, containing or not containing RL, were added. In a volume-dependent and linear manner, solutions containing RL increased the circulating lactate concentration from 10% to > 400% of the baseline lactate value. In a volume-dependent and linear fashion, the non-RL crystalloid solutions decreased the lactate concentration by 0 to 66% of the baseline nondiluted lactate concentration. Experiment 4: In 30 different cardiac surgical patients, we simultaneously obtained central venous and arterial blood specimens. Patients this time received no RL, and catheter lines were adequately cleared (removal > 5 mL) of crystalloid solutions. We found a correlation (r2 = .82; p < .0001) that was virtually identical to the findings of experiment 1 and to the findings in the PTCA group of experiment 2.

CONCLUSIONS

a) Arterial and central venous lactate concentrations are similar in hemodynamically stable critically ill patients, b) Even small amounts of RL-containing solutions in catheters used for blood sampling may cause false increases in the circulating lactate concentration. c) Even small amounts of non-RL crystalloid solutions in catheters used for blood sampling may falsely decrease circulating lactate values. d) When blood specimens are drawn from indwelling catheters, all crystalloid solutions must be cleared from the line.

Intrinsic resistance to T cell infection with HIV type 1 induced by CD28 costimulation

When HIV-infected leukocytes are activated by the CD28 costimulatory receptor, HIV-1 is rapidly cleared from cultures, suggesting that costimulation can render T cells resistant to HIV-1 infection. In this study we tested the hypothesis that enhanced secretion of cytokines or chemokines could account for CD28-induced antiviral effects. In an acute infection system, resistance to infection with macrophage-tropic strains of HIV-1 was shown to be comprised of both soluble and cell-associated components. Induction of HIV-1 resistance was specific for CD28 costimulation, in that a variety of other accessory receptors, such as CD2, CD4, CD5, and MHC class I, failed to confer the antiviral resistance. The soluble component was secreted by both CD4 and CD8 T cells, was not unique to CD28 costimulation, and could be neutralized by removal of C-C chemokines (RANTES (regulated upon activation, normal T cell expressed and secreted) and macrophage inflammatory protein-1alpha and -1beta) from the culture supernatants of costimulated CD4 T cells. In contrast, CD28 stimulation of CD4 cells resulted in the specific induction of a pronounced intrinsic resistance to HIV-1 infection by macrophage tropic isolates of HIV-1.

Intrinsic resistance to T cell infection with HIV type 1 induced by CD28 costimulation

When HIV-infected leukocytes are activated by the CD28 costimulatory receptor, HIV-1 is rapidly cleared from cultures, suggesting that costimulation can render T cells resistant to HIV-1 infection. In this study we tested the hypothesis that enhanced secretion of cytokines or chemokines could account for CD28-induced antiviral effects. In an acute infection system, resistance to infection with macrophage-tropic strains of HIV-1 was shown to be comprised of both soluble and cell-associated components. Induction of HIV-1 resistance was specific for CD28 costimulation, in that a variety of other accessory receptors, such as CD2, CD4, CD5, and MHC class I, failed to confer the antiviral resistance. The soluble component was secreted by both CD4 and CD8 T cells, was not unique to CD28 costimulation, and could be neutralized by removal of C-C chemokines (RANTES (regulated upon activation, normal T cell expressed and secreted) and macrophage inflammatory protein-1alpha and -1beta) from the culture supernatants of costimulated CD4 T cells. In contrast, CD28 stimulation of CD4 cells resulted in the specific induction of a pronounced intrinsic resistance to HIV-1 infection by macrophage tropic isolates of HIV-1.

Differential regulation of HIV-1 fusion cofactor expression by CD28 costimulation of CD4+ T cells

Activation of CD4(+) T lymphocytes from human immunodeficiency virus-type 1 (HIV-1)-infected donors with immobilized antibodies to CD3 and CD28 induces a virus-resistant state. This effect is specific for macrophage-tropic HIV-1. Transcripts encoding CXCR4/Fusin, the fusion cofactor used by T cell line-tropic isolates, were abundant in CD3/CD28-stimulated cells, but transcripts encoding CCR5, the fusion cofactor used by macrophage-tropic viruses, were not detectable. Thus, CD3/CD28 costimulation induces an HIV-1-resistant phenotype similar to that seen in some highly exposed and HIV-uninfected individuals.

Association of interferon-gamma induced growth inhibition and modulation of epidermal growth factor receptor gene expression in squamous cell carcinoma cell lines

Interferons (IFN) possess the ability to inhibit proliferation of certain transformed cell lines. Down modulation of the abnormal expression of certain oncogenes by IFN has been associated with phenotypic reversion of src, myc, or ras transformed cells. It has already been shown that some squamous cell carcinoma (SCCa) cell lines express elevated levels of the epidermal growth factor receptor (EGFR). Previously, in A431, an SCCa cell line, it was shown that IFN-gamma-induced growth inhibition was associated with both enhanced expression of EGFR and terminal differentiation. This study examines the effect of IFN-beta or IFN-gamma on five additional cervical SCCa cell lines. One cell line was shown to have amplification of the EGFR gene. An IFN-gamma induced antiproliferative response, observed in four of the five cell lines, was associated with increased expression of EGFR mRNA and induction of the IFN-inducible genes, HLA-A3 class I antigen and 2-5 oligoadenylate synthetase. These data suggest that the increased expression of the EGFR gene in a particular SCCa may predict response to IFN-gamma.