NewLink Genetics Corporation announced today data from a Phase 1/2 study showing that patients with progressive advanced non-small cell lung cancer treated with its HyperAcute®-Lung cancer immunotherapy experienced favorable median survival. The data were presented at the 101st American Association for Cancer Research (AACR) Annual Meeting.
The study titled "Phase I/II study of antitumor vaccination using lung cancer cells expressing murine alpha(1,3)galactosyltransferase (alphaGT) in non-small cell lung cancer (NSCLC)" involved a unique treatment approach designed to trigger a powerful immune response to cancer cells similar to the hyperacute reactions that occur with xenotransplants (tissues from lower animals transplanted into old-world primates).
"This trial was the first to test this type of immunotherapy in patients, and we are quite encouraged by the findings," said lead investigator John C. Morris, M.D., Co-director of Clinical Trials, Metabolism Branch, National Cancer Institute, Bethesda, MD. "This study showed that HyperAcute-Lung cancer immunotherapy is feasible, safe, and associated with favorable survival in patients with previously-treated, advanced non-small cell lung cancer."
In transplants of human organs such as the kidneys or heart, recipients are at risk of rejecting donor organs because of immune system reactions directed against the foreign tissue. That immune response is dramatically stronger if non-primate organs, for example, pig hearts are transplanted into primates, largely because lower animals express sugar patterns on their cell surfaces that are not expressed in humans. The sugar epitopes, known as alpha(1,3)-galactosyl, or alpha-Gal residues, are powerful antigens that cause a rapid, hyperacute rejection response whenever foreign tissues bearing it are introduced into the human body. The response is strong enough to destroy transplanted cells and tissues within hours. NewLink's HyperAcute immunotherapy exploits this hyperacute antigen-antibody response to educate a patient's immune system to attack and destroy the patient's own unmodified cancer cells.
In this study, conducted at the National Cancer Institute, a total of 17 patients in the Phase 1 portion and 26 patients in Phase 2 portion were injected with an anti-tumor immunotherapy consisting of three types of viable, non-dividing, human lung cancer cells that had been genetically altered to express the mouse gene responsible for making alpha-Gal residues.
"Although cells making up naturally occurring NSCLC tumors in patients do not express alpha-Gal, they share other molecules with the genetically altered lung cancer cells introduced by the vaccine," Dr. Morris added. "Those similarities may allow the antibodies and immune cells targeting alpha-Gal to redirect their attack and destroy patients' own tumor cells."
Phase 1 results showed:
- Six of 16 evaluable patients experienced stabilization of disease for a median of 34.9 weeks.
- No dose-limiting toxicity or serious adverse events were attributed to the HyperAcute-Lung immunotherapy.
Phase 2 results showed:
- Median progression-free survival for the entire group was 15.5 weeks and for patients with stable disease was 28.1 weeks.
- Median overall survival was 52.1 weeks.
- Overall survival correlated with the persistence of anti-alphaGal immunoglobulin (IgG) antibody titers.
- Longer overall survival was associated with increased gamma-interferon (IFNg) secretion by peripheral blood mononuclear cells (PBMC's) post-vaccination in an ELISPOT assay in those patients in which the assay was performed.
"NewLink has a broad and growing platform of tumor-specific immunotherapies based on our HyperAcute technology," said Charles Link, M.D., chairman and chief executive officer of NewLink Genetics Corporation. "In addition to this promising new lung cancer data, we have started screening patients for a pivotal Phase 3 trial of HyperAcute-Pancreas immunotherapy in patients with pancreatic cancer."
NewLink is currently advancing four product candidates in human clinical trials. Its HyperAcute immunotherapy for pancreatic cancer will enroll about 700 previously untreated patients with resected pancreatic cancer. This Phase 3 trial will randomly assign patients to receive either the current standard of care or the current standard of care plus the NewLink HyperAcute pancreatic cancer immunotherapy. The HyperAcute product for melanoma is showing early promise in a small, investigator-sponsored Phase 2 study. Data from Phase 2 studies of the NewLink pancreatic cancer and melanoma immunotherapies will be presented at ASCO in June 2010. NewLink is also developing a first-in-class, small-molecule inhibitor of the indoleamine 2,3 dioxygenase (IDO) pathway, which is presently undergoing Phase 1 safety testing and which the company plans to move into Phase 2 studies later this year.
The company's HyperAcute products are composed of irradiated, allogeneic (off the shelf), whole cancer cells that have been genetically modified to add alpha-Gal residues to cell-surface lipids and proteins. The alpha-Gal epitopes function as a molecular adjuvant, effectively harnessing this xenotransplant rejection mechanism.