June 22, 2017
2 min read

FDA approves optical imaging agent to assist in resection of high-grade glioma

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The FDA approved aminolevulinic acid hydrochloride as an optical imaging agent indicated for patients with gliomas as an adjunct for the visualization of malignant tissue during surgery, according to the agent’s manufacturer.

Patients take the oral compound 3 hours before undergoing surgery, so the drug reaches the brain tumor and is metabolized into a fluorescent form to enable fluorescence-guided surgery, according to Costas Hadjipanayis, MD, PhD, chair of the department of neurosurgery at Mount Sinai Beth Israel and director of neurosurgical oncology for the Mount Sinai Health System.

“One of the biggest challenges with resecting malignant brain tumors is that they’re infiltrative,” Hadjipanayis, who was the first to use the product in 2011 and who oversaw clinical trials leading to the drug’s approval, said in a press release. “They have little tentacles growing into the normal brain that are challenging to see even with a microscope. This technology allows us to visualize those fingers of tumor tissue.

“Any technology that allows us to visualize the tumor in real time and permit us to safely resect the tumor and differentiate it from the real brain is a game changer,” Hadjipanayis added.

Three clinical trials evaluated 20 mg/kg aminolevulinic acid hydrochloride (Gleolan, NX Development Corp) in patients who had a preoperative MRI indicating high-grade glioma and were undergoing surgical resection.

Study 1 included 33 patients with newly diagnosed glioma and study 2 included 36 patients with recurrent glioma. These studies compared positive vs. negative fluorescence with true vs. false tumor status using histopathology as the reference standard.

Study 3 included 415 patients with a preoperative diagnosis of high-grade glioma by MRI who researchers randomly assigned to receive aminolevulinic fluorescence or white light.

In total, researchers found true-positive biopsies — or those positive by histopathology and fluorescence — in 178 patients in study 1, 342 patients in study 2, and 312 in study 3. False-positive biopsies — or those negative by histopathology and positive by fluorescence — occurred in seven patients from study 1, 12 in study 2, and seven in study 3.

In addition, true-negative biopsies occurred in 27 patients in study 1, three patients in study 2, and 30 patients in study 3, whereas false-negative biopsies occurred in 85 patients in study 1, 13 in study 2, and 130 patients in study 3.

In study 3, 64% of patients given aminolevulinic fluorescence demonstrated complete resection compared with 38% of patients in the control arm (difference, 26%; 95% CI, 16-36).


Five clinical trials, which included 527 patients with glioma, showed aminolevulinic fluorescence increased risk for phototoxic reactions, hypersensitivity reactions and interpretation errors.

Adverse reactions in the week following surgery included pyrexia, hypotension, nausea and vomiting. Chills, photosensitivity reaction, solar dermatitis, hypotension, abnormal liver function test and diarrhea occurred in the first 6 weeks after surgery.

The FDA recommended an oral dose of 20 mg/kg aminolevulinic acid hydrochloride administered 3 hours prior to induction of anesthesia.

“We can better visualize the tumor after Gleolan administration, so a maximal, safe resection can be performed to provide better outcomes for our patients,” Hadjipanayis said. “Patients can also go onto other therapies for treatment of their brain tumor. We’re very excited to offer this technology to our patients.”