Agenus Inc., a developer of treatments for cancer and infectious diseases, plummeted the most in four years after partner GlaxoSmithKline Plc’s MAGE-A3 vaccine failed to help skin-tumor patients in a trial.
Agenus, which developed the stimulating component of the experimental treatment, fell 23 percent to $2.84 at the close in New York, its biggest drop since October 2009. The shares of the Lexington, Massachusetts-based biotechnology company have declined 31 percent this year.
The late-stage study will continue to see whether the medication helped a specific subset of patients with melanoma, London-based Glaxo said in a statement today. Results are expected in 2015, Glaxo said. MAGE-A3 is an immunotherapy, a promising area of research where treatments stimulate the immune system to recognize and attack cancer cells.
Estimates for MAGE-A3 were “heavily risk-adjusted” by analysts, Alistair Campbell, an analyst with Berenberg in London, said in an interview. “Expectations weren’t high,” said Campbell, who said he doesn’t expect the drug to meet the secondary goals of the trial.
Glaxo declined less than 0.8 percent to 1,652.50 pence in London. The stock has increased 24 percent this year.
The treatment is designed to work by targeting the melanoma-associated antigen 3, or MAGE-A3, a protein that is expressed in certain cancer cells and not in healthy cells. The trial assessed the time between treatment with the vaccine and the first sign that the disease recurred, or when the patient died.
Glaxo will study whether the drug works in a subgroup of patients who may respond better to the drug based on their genetic makeup. If successful, the company may file for marketing approval for that group of patients, Agenus said in a separate statement today.
Glaxo is also studying MAGE-A3 in lung cancer and results of a late-stage trial are expected in the first half of next year.
Merck KGaA said Dec. 19 that its cancer vaccine L-BLP25 failed to help lung cancer patients live longer in a late-stage trial. The Darmstadt, Germany-based pharmaceutical company is reviewing whether it will conduct another large trial focusing on a specific group of patients who showed a positive response to the treatment, which targets cancer cells where the MUC1 gene is present.
In an Aug. 6 research note, Citigroup Inc. said there was a low probability of success for MAGE-AG and dabrafenib.