Oncology

The purpose of the research was to determine whether supplementation of TPN with glutamine enhances the process of immune reconstitution and improves the mucositis score of patients undergoing high-dose chemotherapy and autologous peripheral blood stem-cell transplantation (aPBSCT) or immunoselected CD34+aPBSCT for hematologic malignancies.

• Patients admitted for selected or unselected aPBSCT at the Hematology Department, Catholic University A. Gemelli Hospital, Rome, Italy
• Informed consent obtained from all patients/guardians.

Not mentioned.

Recruitment

• Study 1: 27 consecutive patients of the Catholic University "A Gemelli" hospital, Rome, Italy, admitted to selected or unselected aPBSCT between October 1998 and August 1999
• Study 2: 21 consecutive patients of the Catholic University "A Gemelli" hospital, Rome, Italy, admitted to selected or unselected aPBSCT beginning in September 1999.

Design

• Study protocol approved by institutional review board
• The trial consisted of two consecutive randomized controlled studies.

Blinding used

• Some study personnel were blinded
• No specific statement on blinding.

Intervention

Study One (October 1998 to August 1999)

• 27 consecutive patients admitted for selected or unselected aPBSCT were randomized to one of two groups:
  • Study One Glutamine group, 12 patients
    • Received Glamin (Fresenius Kabi), a parenteral amino acid solution containing 20 g free glutamine, 1,000 mL/day, from Day +1 after aPBSCT
  • Study One placebo group, 15 patients
    • Received a placebo.
• Daily parenteral nutrition regimen
  • Glutamine group
    • Intralipid: 10% (Fresenius Kabi), 500 ml
    • Glamin: (Fresenius Kabi), 1,000 ml
      • 18 essential and non-essential amino acids
      • 30.27 g stable glycil-L-glutamine
      • 10.27 g glycine
      • 20 g glutamine.
    • 33% glucose solution, 1,000 ml
    • Hydrosoluble and liposoluble vitamins.
  • Placebo group
    • Intralipid: 10% (Fresenius Kabi), 500 ml
    • Freamine: 8.5% (Fresenius Kabi), 1,000 ml
    • 33% glucose solution, 1,000 ml
    • Hydrosoluble and liposoluble vitamins.

Study Two (Beginning September 1999)

• 21 consecutive patients admitted for selected or unselected aPBSCT were randomized to one of two groups:
  • 10 patients (Study Two Glutamine group)
    • Received Dipeptiven (Fresenius Kabi), a parenteral solution containing 13.46 g glutamine, 100 mL/day, from Day +1 after aPBSCT.
  • 11 patients (Study Two placebo group)
    • Received a placebo.
• Daily parenteral nutrition regimen
  • Glutamine group:
    • Kabimix 1830 (Fresenius Kabi)
    • Dipeptiven (Fresenius Kabi), 100 mL
    • Hydrosoluble and liposoluble vitamins.
  • Placebo group:
    • Kabimix 1830 (Fresenius Kabi)
    • Hydrosoluble and liposoluble vitamins.

Interventions for all patients, both studies:

• Prophylactic antibiotics
• Broad-spectrum antibiotics for sustained fever >38° C
• RBC infusions if RBC<8g/dL
• Platelet infusions if platelets <15x10⁹/L
  • All blood products were irradiated.

Statistical Analysis

Statistical significance defined as P<0.05

• Analysis of continuous factors: Mann-Whitney U-test
• Multiple comparisons: Kruskal-Wallace
• Post-hoc evaluation: Dunn's test
• Analysis of categorical factors: x² test.

Data from Study One and Study Two were analyzed separately; then data from both studies was pooled and analyzed to check for consistency.

Timing of Measurements

• Clinical outcomes were evaluated daily
• Immune recovery was measured by lymphocyte subset analysis at baseline, 15, 30, 60, and 90 days
• Mucositis was assessed daily.

Dependent Variables related to cancer symptoms (for both Study One and Study Two)

• Variable One: Clinical outcomes
  • Days of hospitalization (in days)
  • Days of non-prophylactic antibiotics (in days)
  • Number of days with body temperature >38° (in days).
• Variable Two: Immune recovery
  • Lymphocyte subset analysis
    • Measured by flow cytometry at baseline, 15, 30, 60, and 90 day.
• Variable Three: Severity of mucositis
  • Measured daily from day 0 to discharge by Daily Mucositis Score (DMS).

Independent Variables

• Study One: Glamin (Fresenius Kabi), a parenteral amino acid solution containing 20 g free glutamine, 1000 mL/day, from Day +1 after aPBSCT.
• Study Two: Dipeptiven (Fresenius Kabi), a parenteral solution containing 13.46 g glutamine, 100 mL/day, from Day +1 after aPBSCT.

Control Variables

• Study One: Placebo solution.
• Study Two: Placebo solution.

Initial and Final N (no attrition)

• Study One: N=27
  • 12 treatment (five females, seven males)
  • 15 placebo (five females, 10 males).
• Study Two: N=21
  • 10 treatment (five females, five males)
  • 11 placebo (three females, eight males).

Mean Age

• Study One 
  • Treatment group: 37.5 years
  • Placebo group: 47 years.
• Study Two
  • Treatment group: 31.5 years 
  • Placebo group: 49 years.

Ethnicity

• Not mentioned.

Other relevant differences between groups

• There were no significant differences between the Study One and Study Two groups in age, sex, conditioning regimen, and diagnosis.

Location

• Hematology Institute, Catholic University "A Gemelli" Hospital, Rome, Italy.

*Measured as PMNs (polymorphonuclear granulocytes)

Summary of pooled data

• Researchers pooled data from Study One and Study Two. Findings included:
  • Glutamine-supplemented patients had a significantly lower DMS on Day 10 (2 vs. 5; P=0.046), Day 11 (2 vs. 5; 0.016), and Day 12 (1.5 vs. 3.5; P=0.041)
  • Glutamine-supplemented patient days at peak mucositis score was significantly lower (6 vs. 7; P=0.047)
  • Glutamine-supplemented patients had better immune reconstitution:
    • Higher number CD4+ cells at Day +15 (106 vs. 59 cells/µg; P=0.016), Day +30 (191 vs. 116 cells/µg; P=0.026).
• There were no other significant differences between the treatment and control groups when pooled data was analyzed.    

• Both studies showed that parenteral glutamine supplementation strongly improved immune reconstitution in autologous transplant patients, probably through rapid CD4+ subset reconstitution and the limiting of NK overshoot after transplant.
• Both studies showed that parenteral glutamine supplementation significantly reduced peak mucositis and reduced the duration of mucositis and that the effect was dose-related.
  • Study One patients who received 20 g glutamine showed a significantly lower mucositis peak than placebo
  • Study Two patients who received 13.46 g glutamine showed a trend toward reduced mucositis peak.
• Reduction of mucositis may result in better compliance with high-dose chemotherapy by reducing infections
• Positive effects of parenteral glutamine supplementation were balanced by much higher costs of parenteral nutrition.

• Discussion of blinding was not thorough
• Implementation of the second study was not planned in the original study design
• Both Study One and Study Two showed a large difference in mean age of treatment and control groups, suggesting that positive effects could have been related to difference in age
• Generalizability of study may be limited by small sample of patients who received generally heterogenous conditioning regimens.