Aimmune Therapeutics Reports Discussed Phase 2 Data on AR101 for Treatment of Peanut Allergy at FARE Research Retreat

Aimmune Therapeutics, Inc.

, a biopharmaceutical company developing CODIT™ (Characterized Oral Desensitization ImmunoTherapy) treatments for life-threatening food allergies, today announced that the company's CEO, Stephen Dilly, M.B.B.S., Ph.D., presented data over the weekend as part of its participation in the annual Food Allergy Research and Education (FARE) Research Retreat. In addition to reviewing efficacy and safety data from Phase 2 trials of Aimmune's lead product, AR101 for the treatment of peanut allergy, Dr. Dilly also discussed biomarker data from the studies. "It was particularly pleasing to share these important findings with many of the same food allergy leaders whose vision to pursue FDA approval for an oral immunotherapy product led to the formation of our company," said Dr. Dilly. "Potentially the most exciting new finding we presented this weekend was the very clear partitioning of patient outcomes in our Phase 2 studies based on pre-treatment baseline peanut-specific IgE (psIgE) values." All 55 patients who entered the ARC001 and ARC002 Phase 2 trials had documented psIgE values at pre-treatment baseline: 28 had values above 100 kUA/l and 27 had values of 100 kUA/l or less. In the 27 patients with psIgE ≤100 kUA/l, there were no treatment-related withdrawals, no serious adverse events, and no epinephrine use, and all patients met the primary endpoint at the double-blind, placebo-controlled food challenge administered at the end of up-dosing. There was a single withdrawal from this group due to scheduling issues. Conversely, in the 28 patients from the higher psIgE group, there were 10 treatment-related withdrawals and one patient failed the exit challenge, giving an overall treatment success rate of 61 percent in this group. Other baseline measures, including skin prick test and maximum tolerated dose at entry double-blind, placebo-controlled food challenge, were not conspicuously different between patients who completed up-dosing and those who discontinued treatment during up-dosing. "If replicated in our ongoing Phase 3 PALISADE trial, we believe that these findings could have very positive implications for the adoption of AR101 in clinical practice," continued Dr. Dilly. "According to the published scientific literature, at least 80 percent of untreated people with peanut allergy have psIgE levels below 100 kUA/l, and, importantly, there seems to be no clear correlation between psIgE levels and reaction threshold or severity of reaction." "Our Phase 2 data suggest that peanut-specific IgE levels could play an important role in identifying patients at increased risk for side effects, particularly gastrointestinal side effects, from oral immunotherapy. We are eager to see if this pattern around peanut-specific IgE levels will be confirmed in our Phase 3 PALISADE trial. If it is, we believe that a simple predictive test could ultimately help guide the course of oral immunotherapy," said Aimmune's Chief Medical Officer, Robert Elfont, M.D., Ph.D. "Although patients with high peanut-specific IgE levels, in Phase 2, had a rockier course with up-dosing, it is interesting to note that the efficacy signal in completers was similar across all patients, independent of psIgE levels." As previously reported, treatment with AR101 was associated with significantly increased peanut-specific IgG4 antibodies and a significantly decreased ratio of psIgE to IgG4. Also, the median peanut skin prick test wheal size declined meaningfully from measurements taken before treatment to those taken after patients had completed the AR101 up-dosing regimen. In a separate presentation at the Research Retreat, Erik Wambre, Ph.D., of the Benaroya Research Institute (BRI) discussed research from his lab focusing on peanut-specific Th2 lymphocytes. His talk included data from a small pilot study of participants in Aimmune's Phase 2 trials, which he previously discussed at the 2016 American Academy of Allergy, Asthma & Immunology (AAAAI) Annual Meeting in March. In these preliminary studies, activated peanut-specific Th2 cells were greatly reduced in the blood of subjects receiving active treatment, but not placebo, suggesting that AR101 specifically modulated key lymphocyte populations responsible for peanut allergy. Aimmune and BRI have an ongoing partnership and plan to expand these and other related studies during the Phase 3 PALISADE trial, with generous support from the Immune Tolerance Network. "These data are extremely encouraging because they demonstrate that the reduction in clinical reactivity following treatment with AR101 is clearly linked to reduction of the pathogenic T cells associated with peanut allergy, and other quantifiable changes in the immune repertoire," said Dr. Wambre. "We look forward to better understanding the ability of AR101 to reprogram the immune system by expanding our studies — not only in T cells but also B cells, basophils, and antibodies — in many more participants from Aimmune's ongoing Phase 3 trial. It is exciting to be a part of the biggest peanut immunotherapy study ever undertaken because the large sample will give us unprecedented power to detect biomarkers of treatment response."