• Between 18 and 85 years of age (inclusive) at the initial screening visit;

• Meets 2011 consensus criteria for svPPA (Gorno-Tempini et al. 2011);

• MRI at screening is consistent with the underlying svPPA with no large strokes or severe white matter disease (Fazekas Grade ≤2; Fazekas et al. 1987);

• CDR® plus NACC FTLD (Miyagawa et al. 2020) global score at screening ≤1;

• The following medications are allowed, but must be stable for 2 months prior to the initial screening visit:

∙ Food and Drug Administration (FDA)-approved Alzheimer's disease (AD) medications;

‣ FDA-approved psychotropic medications;

• Other medications (except those listed under exclusion criteria) are allowed as long as the dose is stable for 30 days prior to the initial screening visit;

• Has a reliable study partner who agrees to accompany the participant to visits, and spends at least 5 hours per week with the participant;

• Agrees to 2 LPs;

• Signed and dated written informed consent obtained from the participant and the participant's study partner in accordance with local Institutional Review Board (IRB) regulations;

⁃ WOCBP must agree to abstain from sex or use highly effective birth control that includes two methods of contraception (one of which must be a barrier method) for the duration of the screening period, the RDBPC treatment period, and for 30 days after the last dose of study drug (active or placebo);

⁃ Males must agree to abstain from sex with WOCBP or use an adequate method of contraception for the duration of the RDBPC treatment period and for 90 days after the last dose of study drug (active or placebo);

⁃ Able to swallow pills whole without crushing or chewing.