skip navigation

Skip Nav

AIDSinfo Drug Database

AIDSinfo Drug Database

Drugs by class



Rintatolimod  Audio icon

Other Names: AMP, Ampligen, Atvogen, poly(I)-poly(C12U), poly(I:C12U), polyI:polyC12U
Drug Class: Biological Response Modifiers
Molecular Formula: (C10 H13 N4 O8 P)x.(C9 H14 N3 O8 P.C9 H13 N2 O9 P)x
Registry Number: 38640-92-5 (CAS)
Chemical Name: 5'-Inosinic acid, homopolymer, complex with 5'-cytidylic acid polymer with 5'-uridylic acid (1:1)
Chemical Class: Oligonucleotides
Company: Hemispherx; Rega Institute For Medical Research
Phase of Development: Phase II

Chemical Image:
Click image to enlarge
Molecular Weight: 995.584
(Compound details obtained from ChemIDplus Advanced1 and NIAID Therapeutics Database2)

What is an investigational drug?

An investigational drug is one that is under study and is not approved by the U.S. Food and Drug Administration (FDA) for sale in the United States. Medical research studies are conducted to evaluate the safety and effectiveness of an investigational drug. These research studies are also called clinical trials. Once an investigational drug has been proven safe and effective in clinical trials, FDA may approve the drug for sale in the United States.

To learn more about investigational drugs, read the AIDSinfo What is an Investigational HIV Drug? fact sheet.

What is rintatolimod?

Rintatolimod is an investigational drug that is categorized as a biological response modifier.2 Biological response modifiers (also called immunomodulators) are substances that help to activate, boost, or restore normal immune function.3,4

Rintatolimod was studied for its ability to delay re-emergence of HIV during treatment interruptions of antiretroviral therapy (ART). A treatment interruption is a planned break from ART to evaluate how well an investigational drug can maintain control of a participant’s viral load during a clinical trial. (Viral load is the amount of HIV in a blood sample.) Interruption of ART is not recommended outside of controlled clinical trials.5,6

Also, rintatolimod has been studied for various non-HIV-related uses, including to treat chronic fatigue syndrome and cancer and to boost the body’s immune response to a flu vaccine.7-10

How are clinical trials of investigational drugs conducted?

Clinical trials are conducted in phases. Each phase has a different purpose and helps researchers answer different questions.11

  • Phase I trials: Researchers test an investigational drug in a small group of people (20–80) for the first time. The purpose is to evaluate its safety and identify side effects.
  • Phase II trials: The investigational drug is administered to a larger group of people (100–300) to determine its effectiveness and to further evaluate its safety.
  • Phase III trials: The investigational drug is administered to large groups of people (1,000–3,000) to confirm its effectiveness, monitor side effects, compare it with standard or equivalent treatments, and collect information that will allow the investigational drug to be used safely.11

In most cases, an investigational drug must be proven effective and must show continued safety in a Phase III clinical trial to be considered for approval by FDA for sale in the United States. Some drugs go through FDA’s accelerated approval process and are approved before a Phase III clinical trial is complete. After a drug is approved by FDA and made available to the public, researchers track its safety in Phase IV trials to seek more information about the drug’s risks, benefits, and optimal use.11

In what phase of testing is rintatolimod?

Rintatolimod for HIV treatment has been studied in Phase II clinical trials.2

What are some studies on rintatolimod?

Study Name: AMP 720; NCT0035893
Phase: IIb
Location: United States

  • Participants were HIV-infected adults who had taken HIV medicines before entering the study (treatment-experienced).
  • Participants’ HIV levels were under control, with a viral load level of less than 50 copies/mL while on ART.
  • Participants had a CD4 count greater than 400 cells/mm3. (A CD4 count is a laboratory test that measures the number of CD4 cells in a sample of blood and is an important indicator of immune function. The CD4 count of a healthy person ranges from 500 to 1,600 cells/mm3.)
Purpose: The purpose of this study was to evaluate whether rintatolimod could extend the time people could stay off HIV medicines during interruptions of ART (planned breaks from treatment) before their HIV began to rebound. (A rebound is when there are detectable levels of HIV in the blood after a period of undetectable levels.)5,6

For more details on this study, see the Health Professional version.

Another Phase II study of rintatolimod (known as AMP 719; NCT00355581) was also planned to take place. In AMP 719, investigators were planning to study the safety and effectiveness of adding twice weekly rintatolimod to ART in people whose HIV medicines weren’t controlling their HIV infection. This study, however, was stopped and was not completed.12

What side effects might rintatolimod cause?

In the Phase II study looking at the use of rintatolimod during interruptions of ART, side effects were generally mild and cleared up without treatment.6

Information on possible side effects of rintatolimod is not complete. As testing of rintatolimod continues, additional information on possible side effects will be gathered.

Where can I get more information about clinical trials studying rintatolimod?

More information about rintatolimod-related research studies is available from the AIDSinfo database of study summaries. Click on the title of any trial in the list to see the trial summary and more information about the study.

How can I find more information about participating in a clinical trial?

Participating in a clinical trial can provide benefits. For example, a volunteer participant can benefit from new research treatments before they are widely available. Participants also receive regular and careful medical attention from a research team that includes doctors and other health professionals. However, clinical trials may also involve risks of varying degrees, such as unpleasant, serious, or even life-threatening side effects from the treatment being studied.11

Your health care provider can help you decide whether participating in a clinical trial is right for you. For more information, visit NIH Clinical Research Trials and You.


  1. United States National Library of Medicine. ChemIDplus Advanced. Available at: Last accessed on June 20, 2016.
  2. National Institute of Allergy and Infectious Diseases (NIAID). NIAID ChemDB, HIV Drugs in Development. Available at: Last accessed on June 20, 2016.
  3. AIDS Clinical Trials Group (ACTG) Network website. Glossary of HIV-Related Terms. Definition for Biological Response Modifier (BRM). Available at: Last accessed on June 20, 2016.
  4. HealthHIV website. HIV Glossary of Terms. Definition for Biological Response Modifier (BRM). Available at: Last accessed on April 16, 2014.
  5. Hemispherx Biopharma. The Role of Ampligen in Strategic Therapeutic Intervention (STI) of Highly Active Anti-Retroviral Therapy (HAART): A Multi-Center, Randomized, Controlled Study of Ampligen Potentiation of the HAART-Free Interval. In: Bethesda (MD): National Library of Medicine (US). Registered on May 6, 2002. NLM Identifier: NCT00035893. Available at: Last accessed on June 20, 2016.
  6. Blick G, Greiger-Zanlungo P, Strayer DR, Mitchell WM, Carter WA. INTERIM RESULTS OF AMP720: A PHASE IIB PROSPECTIVE, RANDOMIZED, CONTROLLED STUDY EVALUATING THE IMMUNOMODULATORY ROLE OF AMPLIGEN (POLY I:POLY C12U) AGAINST HIV DURING STI. 2nd International AIDS Society (IAS) Conference on HIV Pathogenesis and Treatment; July 13-16, 2003; Paris, France. Abstract 596. Available at: Last accessed on June 20, 2016.
  7. Strayer DR, Carter WA, Stouch BC, et al. A Double-Blind, Placebo-Controlled, Randomized, Clinical Trial of the TLR-3 Agonist Rintatolimod in Severe Cases of Chronic Fatigue Syndrome. PLoS One. 2012;7(3):e31334. Available at: Last accessed on June 20, 2016.
  8. University of Washington. Phase I-II Study of HER2 Vaccination With Poly(I) • Poly(C12U) (Ampligen®) as an Adjuvant in Optimally Treated Breast Cancer Patients. In: Bethesda (MD): National Library of Medicine (US). Registered on May 16, 2011. NLM Identifier: NCT01355393. Available at: Last accessed on June 20, 2016.
  9. Pawel Kalinski. Randomized Phase I/II Evaluation of Neoadjuvant Administration of a Chemokine-Modulatory Regimen in Patients With Recurrent Resectable Colorectal Cancer. In: Bethesda (MD): National Library of Medicine (US). Registered on February 29, 2012. NLM Identifier: NCT01545141. Available at: Last accessed on June 20, 2016.
  10. Hemispherx Biopharma. A Phase I/II, Two-Staged, Single-Center, Randomized, Double-Blind, Antibody Titer Study to Assess Immunogenicity and Safety of FluMist® Intranasal Influenza Vaccine Administered With and Without a TLR-3 Agonist, Ampligen®. In: Bethesda (MD): National Library of Medicine (US). Registered on May 2, 2012. NLM Identifier: NCT01591473. Available at: Last accessed on June 20, 2016.
  11. National Institutes of Health (NIH). NIH Clinical Research Trials and You. Available at: Last accessed on June 20, 2016.
  12. Hemispherx Biopharma. A Multi-Center, Randomized, Controlled Study of the Biological Actions of Ampligen as an Adjunct to HAART in HIV Disease. In: Bethesda (MD): National Library of Medicine (US). Registered on May 3, 2002. NLM Identifier: NCT00035581. Available at: Last accessed on June 20, 2016.

Last Reviewed: June 20, 2016

Back to Top