Phase 1 Trial of Na-ASP-2 Hookworm Vaccine in Previously Infected Brazilian Adults


Albert B. Sabin Vaccine Institute

Status and phase

Phase 1


Hookworm Infection


Biological: Na-ASP-2 Hookworm Vaccine

Study type


Funder types




Details and patient eligibility


Na-ASP-2 is a protein expressed during the larval stage of the N. americanus hookworm life cycle. Vaccination with recombinant ASP-2 has protected dogs and hamsters from infection in challenge studies. In a clinical study in hookworm-uninfected adults in the USA, Na-ASP-2 Hookworm Vaccine was safe and immunogenic. This study will evaluate its safety and immunogenicity in individuals living in an area of endemic hookworm infection.

Full description

Double-blind, randomized, controlled Phase 1 clinical trial. Study site: Americaninhas, Minas Gerais, Brazil. Number of participants: 48 in three groups of 16, randomized to receive either Na-ASP-2 Hookworm Vaccine (n=36) or Butang® hepatitis B vaccine (n=12). Study duration: 48 weeks; each participant will be followed for a total of 42 weeks. Immunization schedule: Study days 0, 56 and 112. Route: IM in the deltoid muscle. Dose of Na-ASP-2: 10, 50 and 100 µg for the first, second and third dose cohort, respectively. Dose of Alhydrogel®: 800 µg for each dose of Na-ASP-2.


9 patients




18 to 45 years old


Accepts Healthy Volunteers

Inclusion criteria

  • Males or females between 18 and 45 years, inclusive.
  • Known residents of the Municipality of Novo Oriente de Minas, Minas Gerais, Brazil.
  • Good general health as determined by means of the screening procedure.
  • Completed a 3-dose albendazole treatment for documented hookworm infection during the previous 3 months.
  • Available for the duration of the trial (42 weeks).
  • Willingness to participate in the study as evidenced by signing the informed consent document.

Exclusion criteria

  • Pregnancy as determined by a positive urine β-hCG (if female).
  • Participant unwilling to use reliable contraception methods up until one month following the third immunization (if female).
  • Currently lactating and breast-feeding (if female).
  • Inability to correctly answer all questions on the informed consent comprehension questionnaire.
  • Evidence of clinically significant neurologic, cardiac, pulmonary, hepatic, rheumatologic, autoimmune, or renal disease by history, physical examination, and/or laboratory studies.
  • Behavioral, cognitive, or psychiatric disease that in the opinion of the investigator affects the ability of the volunteer to understand and cooperate with the study protocol.
  • Laboratory evidence of liver disease (alanine aminotransferase [ALT] greater than 64 U/l [females] or greater than 58 U/l [males]).
  • Laboratory evidence of renal disease (serum creatinine greater than 1.1 mg/dl [females] or greater than 1.3 mg/dl [males], or more than trace protein or blood on urine dipstick testing).
  • Laboratory evidence of hematologic disease (absolute leukocyte count <3000/mm3 or >12.5 x 103/mm3; hemoglobin <10.3 g/dl [females] or <11.0 g/dl [males]; absolute lymphocyte count <900/mm3; or platelet count <120,000/mm3).
  • Other condition that in the opinion of the investigator would jeopardize the safety or rights of a volunteer participating in the trial or would render the subject unable to comply with the protocol.
  • Participation in another investigational vaccine or drug trial within 30 days of starting this study.
  • Volunteer has had medical, occupational, or family problems as a result of alcohol or illicit drug use during the past 12 months.
  • History of a severe allergic reaction or anaphylaxis.
  • Severe asthma as defined by the need for regular use of inhalers or emergency clinic visit or hospitalization within the last 6 months.
  • Positive ELISA for HCV.
  • Positive ELISA for HBsAg.
  • Known immunodeficiency syndrome.
  • Use of corticosteroids (excluding topical or nasal) or immunosuppressive drugs within 30 days of starting this study.
  • Receipt of a live vaccine within past 4 weeks or a killed vaccine within past 2 weeks prior to entry into the study.
  • History of a surgical splenectomy.
  • Receipt of blood products within the past 6 months.
  • Previous receipt of a primary series of any hepatitis B vaccine.
  • History of allergy to yeast.

Trial design

9 participants in 2 patient groups

10 mcg Na-ASP-2/Alhydrogel
Experimental group
Na-ASP-2 Hookworm Vaccine
Biological: Na-ASP-2 Hookworm Vaccine
Butang hepatitis B vaccine
Active Comparator group
Hepatitis B Vaccine - comparator vaccine
Biological: Na-ASP-2 Hookworm Vaccine

Trial contacts and locations



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