Phase 3 trial tests antibody therapy to prevent blood cancer infections

Dosing has begun in a Phase 3 clinical trial testing whether the antibody therapy Gamunex-C (immune globulin injection [human], 10% caprylate/chromatography purified) can help prevent serious bacterial infections in people whose blood cancer or its treatment has weakened their immune system.

The trial, dubbed SIGMA (NCT07582432), is expected to enroll nearly 50 adults with chronic lymphocytic leukemia (CLL), multiple myeloma, or non-Hodgkin lymphoma (NHL) who also have secondary antibody deficiency marked by low immunoglobulin levels. In this open-label, single-arm study, all participants will receive Gamunex-C in addition to standard medical treatment. Gamunex-C will be infused into the bloodstream once every four weeks for one year. The study’s main goal is to determine whether the rate of serious bacterial infections is less than one per participant per year.

The SIGMA study is currently recruiting participants at one U.S. site, with four more sites expected to begin recruiting. Grifols, which markets Gamunex-C, is sponsoring the trial.

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“We’re excited about the potential to provide patients with more immunoglobulin [antibody] treatment options to help manage their conditions with flexibility and convenience,” Eduardo Herrero, executive vice president, biopharma industrial and scientific innovation at Grifols, said in a company press release.

Blood cancers like myeloma, CLL, and NHL develop when certain blood-forming or immune cells grow uncontrollably. The growth of these cancer cells can leave the body unable to make enough healthy immune cells or antibodies. Some treatments, including chemotherapy and therapies that target B cells, can also reduce healthy immune cells or antibody levels. Together, the cancer and its treatment can weaken the immune system and increase the risk of infection.

Antibodies, also called immunoglobulins, are proteins the immune system normally produces to help fight infections. Gamunex-C contains purified antibodies that are infused into the bloodstream. The treatment is intended to provide additional antibodies that may help protect against infection when the body is not making enough of its own.

Gamunex-C is currently approved in the U.S. to treat certain immune conditions, but it is not specifically approved for secondary antibody deficiency associated with blood cancer. The SIGMA trial is designed to support a potential expansion of the therapy’s U.S. label to include this population.