Why might this be? Perhaps because more drug is moving from blood to brain in people. To his surprise, he found the drug disappeared from blood at a rate of 2.0 L/day, almost twice as fast as expected based on prior data from monkeys, and much faster than typical monoclonal antibodies, which tend to top out at 0.5 L/day. How much might the brain shuttle boost delivery? Roche’s João Abrantes addressed this question by analyzing data from the human SAD study. They will also measure plasma and cerebrospinal fluid biomarkers including Aβ42, total tau, p-tau, NfL, neurogranin, and sTREM2.īetter Uptake? Preliminary human data on gantenerumab’s brain shuttle version (solid lines) indicates that it is cleared from plasma (blue) faster than a typical IgG (dotted lines), but reaches a higher concentration in cerebrospinal fluid (green) and could clear plaque faster (orange). Unlike the healthy volunteers in the SAD phase, all MAD participants have either prodromal, mild, or moderate AD.īesides measuring pharmacokinetics, -dynamics, and whether the conjugate provokes host antibodies, researchers will explore brain imaging by way of structural MRI, functional MRI, ASL-MRI to measure cerebral perfusion, and DTI-MRI to check the integrity of axonal tracts. Participants will receive seven doses over the 28 weeks of the study, and then be followed for another 28 weeks. Doses are 0.2, 0.6, 1.8, and 3.6 mg/kg, infused every four weeks. It comprises four dose cohorts, with eight people on drug and two on placebo in each. At AAIC 2021, Roche’s Luka Kulic had presented single ascending dose (SAD) results from a first-in-human study of this hybrid molecule, RG6102 ( Mar 2021 conference news).Īt CTAD, Kulic laid out the ongoing multiple ascending dose (MAD) phase of the study. This is currently given as an infusion, and Roche declined to speculate whether it might eventually be a jab under the skin, as well. In this approach, gantenerumab is conjugated to an antibody fragment that recognizes the transferrin receptor, a major entry point through the blood-brain barrier. While a subcutaneous jab has the advantage of being simple, scientists at Roche and elsewhere have been developing an alternative option for years. All participants were invited into the tau PET substudy, as well, although Lane did not say how many joined. About three-quarters of participants were screened for amyloid positivity by PET, and all of them continue to undergo longitudinal scans. Unlike past trials, GRADUATE I and II will include hefty imaging substudies, Lane reported.
The study includes several Asian and South American countries, but none in Africa. In part, this may be because diversity was largely driven by the countries participating, Lane noted. However, like many other trials, there are almost no black participants. The population is somewhat more diverse than those of past trials, about 17 percent Hispanic, 12 percent Asian, and 3 percent Native American. Fifty-five percent of them have mild cognitive impairment, the remainder mild AD dementia. Participants’ average age is 72, and their mean MMSE 24.
The trials will take 27 months, having been extended for three months due to pandemic-related disruptions. GRADUATE I consists of 985 participants from 15 countries GRADUATE II, 981 participants from 19 countries. The two GRADUATE trials are identical, but mostly run in different countries.
Because gantenerumab is injected subcutaneously, participants have the option of administering it at home, thus easing their time commitment and the burden of participating in a long trial. Titration takes nine months, with the first three doses at 120 mg, the next three at 255, and the final three at 510. Unlike in the aducanumab Phase 3 trials, all participants are being titrated up to the maximum dosage on the same schedule, regardless of their APOE genotype. Armed with these data, they picked a 1,020 mg monthly subcutaneous dose for Phase 3.Īt CTAD, Lane described the scheme. They found that fivefold higher dosing robustly removed plaque, such that participants became amyloid-negative within two or three years ( Dec 2017 conference news Dec 2019 conference news). Preliminary data suggests it could move twice as much antibody into the brain as expected.Īfter the negative result of the Phase 2 SCarlet RoAD and Marguerite RoAD trials, Roche scientists explored different doses in open-label extension trials ( Dec 2014 news).Roche’s brain shuttle technology is being tested in AD patients.GRADUATE trials expanded diversity, brain imaging over past trials.