A Phase 1 Study of Mixed Bacteria Vaccine (MBV) in Patients With Tumors Expressing NY-ESO-1 Antigen

A Phase 1 Study of Mixed Bacteria Vaccine (MBV) in Patients With Tumors Expressing NY-ESO-1 Antigen.

This was a phase 1, open-label, multiple dose, single-arm study. The mixed bacteria vaccine (MBV) was administered at a starting dose of 250 EU (1 µL) and escalated in each subject to a dose inducing the desired pyrogenic effect, defined as a body temperature of 38°C to 39.5°C. The primary objective was to determine the safety profile of MBV in subjects with malignant tumors that expressed the NY-ESO-1 antigen and to identify the dose that induced the desired pyrogenic effect. Secondary objectives were to evaluate the immunological effects and tumor response of subjects following vaccination.

Subjects in Cohort 1 were enrolled to receive MBV subcutaneously at a starting dose of 250 EU (1 µL; dose level 1) administered twice weekly. In the absence of a dose-limiting toxicity (DLT), the MBV dose was escalated in each subject to the MBV dose that elicited the desired pyrogenic effect, or up to the maximum dose of 547,000 EU (dose level 8). Once the desired pyrogenic effect was observed, subjects received MBV twice weekly for 4 doses at the pyrogenic dose level.

Subjects in Cohort 2 were enrolled to receive MBV at the pyrogenic dose level (determined to be 60,800 EU [dose level 6]) twice weekly for 6 weeks. Vaccinations were injected intralesionally if possible and subcutaneously if intralesional injection was not possible. If a fever of 39.5°C to 40°C was observed, the subject's dose was reduced to dose level 5 (20,300 EU [81 μL]).

Subjects were observed at the clinic for up to 6 hours following each vaccination, with vital signs measured hourly. At baseline and throughout the study, subjects were assessed for NY-ESO-1-specific humoral and cellular immunity, chemistry, hematology, and cytokine analysis (interleukin [IL]-1, IL-6, interferon [IFN]-γ, and tumor necrosis factor [TNF]-α). Safety was monitored continuously throughout the study.

Inclusion Criteria:

1. Histologically confirmed metastatic melanoma, head and neck cancer, transitional cell carcinoma, sarcoma, gastrointestinal stroma tumor (GIST) or prostate cancer.

2. Tumor expression of NY-ESO-1 by reverse transcriptase and polymerase chain reaction (RT-PCR) analysis, preferably, or immunohistochemistry.

3. Expected survival of at least 6 months.

4. Karnofsky performance status ≥ 70%.

5. Fully recovered from surgery.

6. Declined, intolerated or completed standard therapy defined as follows for each tumor entity:

   1. Melanoma - resistance or intolerance to dacarbazine.
   2. Sarcoma - resistance or intolerance to anthracyclines and to one platinum-containing chemotherapy regimen, no indication for irradiation.
   3. GIST - failure or intolerance of imatinib and sunitinib.
   4. Head and neck cancer - no indication for irradiation, resistance or intolerance to platinum-containing chemotherapy.
   5. Transitional cell carcinoma - resistance or intolerance to cisplatin combined with gemcitabine.
   6. Prostate cancer- failure of antihormonal treatment and resistance or intolerance to docetaxel.
   7. Ovarian carcinoma - failure of standard chemotherapy consisting of a platinum agent combined with a taxane and of an anthracycline.
   8. Esophageal cancer - failure of standard chemotherapy consisting of a platinum agent.
   9. Breast cancer- failure or intolerance of standard first-, second- and third-line chemotherapy consisting of a taxane and anthracycline. No indication or resistance to standard antihormonal treatment. No indication or resistance to human epidermal growth factor receptor (HER)-2-neu targeted therapy. No indication or resistance to irradiation and/or surgery.

7. Within the last 2 weeks prior to study day 1, vital laboratory parameters must have been within the normal range, except for the following laboratory parameters, which must have been within the ranges specified:

   • Absolute neutrophil count (ANC): ≥ 1,000/mm3
   • Platelet count: ≥ 75,000/mm3
   • Alanine aminotransferase (ALT): ≤ 5 x upper limit of normal (ULN)
   • Aspartate aminotransferase (AST): ≤ 5 x ULN
   • Total bilirubin: ≤ 2.5 x ULN
   • Creatinine: ≤ 2 mg/dL

8. Age ≥ 18 years.

9. Able and willing to give written informed consent.

Exclusion Criteria:

1. Clinically significant heart disease (New York Heart Association Class III or IV).
2. Other serious illnesses, e.g., serious infections requiring antibiotics or bleeding disorders.
3. Subjects with serious intercurrent illness requiring hospitalization.
4. Known human immunodeficiency virus positivity.
5. Chemotherapy, radiation therapy or immunotherapy within 4 weeks prior to first dose of study agent (6 weeks for nitrosoureas).
6. Known autoimmune disease (rheumatoid arthritis, systemic lupus erythematosus), as these conditions might have interfered with the evaluation of the induced immune response. Subjects with vitiligo or melanoma-associated hypopigmentation were not excluded.
7. Chronic use of immunosuppressive drugs such as systemic corticosteroids.
8. Other malignancy within 3 years prior to entry into the study, except for treated non-melanoma skin cancer and cervical carcinoma in situ.
9. Mental impairment that may have compromised the ability to give informed consent and comply with the requirements of the study.
10. Lack of availability for immunological and clinical follow-up assessments.
11. Participation in any other clinical trial involving another investigational agent within 4 weeks prior to first dosing of study agent.
12. Pregnancy or breastfeeding.
13. Women of childbearing potential: Refusal or inability to use effective means of contraception.