The Iowa-headquartered firm announced its receipt of the patent today, explaining it covers compounds containing salts and prodrugs of indoximod.
Indoximod (1-methyl-D-tryptophan) inhibits an enzyme called indoleamine dioxygenase (IDO) that degrades tryptophan, an amino acid involved in damping down unwanted T-cell response.
The enzyme is also thought to allow cancerous cells to escape detection.
CEO Charles Link Jr. said: “This decision by the US patent office represents a key milestone in the alignment of indoximod’s global patent strategy with our clinical development path."
News of the patent comes months after the publication of research indicating that indoximod improves the efficacy of several cancer treatments.
On June 5 data from a Phase II trial released at the American Society of Clinical Oncology (ASCO) conference suggested that indoximod makes the prostate cancer cell therapy Provenge (Sipuleucel-T) more effective, roughly doubling the time to disease progression.
Earlier in the year, at the American Association of Cancer Research (AACR) meeting, data from a separate study indicated Keytruda (pembrolizumab) combined with indoximod is more effective at treating skin cancer than the monoclonal antibody alone.
In addition, preclinical data - also presented at the AACR conference – showed that an indoximod prodrug – called NLG802 – was effective at increasing serum concentrations of the drug.
Breast cancer disappointment
The positive patent news and trial results are in contrast with data from a Phase II study of indoximod in the treatment of metastatic breast cancer.
On June 2 Newlink announced that indoximod combined with taxane chemotherapy had not achieved a statistically significantly increase in progression-free survival compared with chemotherapy alone.
The firm said full results from the trial will be presented at an upcoming academic meeting.