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Study on mRNA-3705 for Patients with Methylmalonic Acidemia Due to Methylmalonyl-CoA Mutase Deficiency

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying a rare genetic condition called Isolated Methylmalonic Acidemia (MMA), which is caused by a deficiency in an enzyme known as Methylmalonyl-CoA Mutase. This enzyme deficiency leads to the accumulation of certain substances in the body, which can cause serious health problems. The study is testing a new treatment called mRNA-3705, which is designed to help the body produce the missing enzyme. This treatment is given as an injection into a vein, which is known as an intravenous injection.

The purpose of the study is to evaluate the safety and effectiveness of mRNA-3705 in people with MMA. The study is divided into two parts. In the first part, researchers will focus on understanding how safe and tolerable the treatment is for participants. In the second part, they will look at how well the treatment works by comparing the frequency of metabolic decompensation events (MDEs), which are episodes when the body cannot properly process certain substances, with the standard care currently available.

Participants in the study will receive the treatment and be monitored over time to see how their bodies respond. The study will also measure changes in the levels of certain substances in the blood, as well as any side effects that may occur. This research aims to provide valuable information that could lead to better treatment options for people living with Isolated Methylmalonic Acidemia.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, the participant must be at least 1 year old and weigh at least 11 kg. A diagnosis of isolated methylmalonic acidemia (MMA) due to methylmalonyl-CoA mutase (MUT) deficiency must be confirmed through genetic testing.

    Blood vitamin B12 levels must be within the normal range. If elevated, the cause should be due to B12 supplementation, as determined by the investigator.

  2. Step 2

    Initial assessment

    An initial assessment will be conducted to evaluate the participant's health status and eligibility. This includes confirming the diagnosis and checking blood vitamin B12 levels.

  3. Step 3

    Administration of mRNA-3705

    The study involves the administration of mRNA-3705, which is a modified messenger RNA (mRNA) injection. This is given intravenously (through a vein).

    The purpose of this phase is to evaluate the safety and tolerability of the treatment.

  4. Step 4

    Monitoring and follow-up

    Participants will be monitored for any side effects or adverse events. This includes tracking the incidence and severity of any treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs).

    Blood levels of methylmalonic acid and other parameters will be measured to assess the treatment's effects.

  5. Step 5

    Evaluation of efficacy

    The efficacy of mRNA-3705 will be evaluated by comparing the frequency of metabolic decompensation events (MDEs) with standard care.

    Changes in blood methylmalonic acid levels and other health indicators will be assessed over the course of the study.

  6. Step 6

    Completion of the study

    The study is expected to conclude by May 2027. Participants will have completed all required assessments and treatments by this time.

    Final evaluations will be conducted to determine the overall safety and efficacy of the treatment.

Who can join the trial?

8 criteria

  • The participant must be at least 1 year old at the time of giving consent to join the study.
  • The participant must weigh at least 11.0 kg during the initial screening visit.
  • The participant must have a confirmed diagnosis of **isolated Methylmalonic Acidemia (MMA)** due to **Methylmalonyl-CoA Mutase (MUT) deficiency**. This is confirmed through specific genetic testing.
  • The participant's blood level of **vitamin B12** must be at or above the normal range. If the vitamin B12 level is high, the participant can still join if the increase is due to taking vitamin B12 supplements, as determined by the study doctor.
  • The participant or their legal representative must be willing and able to give consent to participate in the study and agree to follow the study procedures.
  • Females who can have children and males who can father children must agree to use a highly effective form of birth control during the study and for 3 months after the last dose of the study drug.
  • The participant must have certain health parameters that show the severity of MMA, as described in the study details.
  • For Part 2 of the study, the participant must have had at least one documented **Metabolic Decompensation Event (MDE)** in the 12 months before giving consent. An MDE is a health event related to the condition being studied.

Who cannot join the trial?

7 criteria

  • Participants who have any other serious health conditions that could interfere with the study.
  • Individuals who are currently taking medications that might affect the study results.
  • Participants who have had a recent infection or illness that could impact their health during the study.
  • Individuals who have a history of allergic reactions to similar treatments.
  • Participants who are pregnant or breastfeeding.
  • Individuals who have participated in another clinical trial recently.
  • Participants who are unable to follow the study procedures or attend the required visits.
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Investigated drugs

mRNA-3705 is an investigational medication being studied for its potential to treat isolated Methylmalonic Acidemia (MMA) due to Methylmalonyl-CoA Mutase (MUT) deficiency. This medication is administered through an intravenous (IV) infusion. The study aims to assess how safe and tolerable this medication is for participants, as well as how it affects the body and how the body processes it. Additionally, the study seeks to determine if mRNA-3705 can reduce the frequency of metabolic decompensation events (MDEs) compared to the standard care currently available for this condition.

What is already known about the treatment

mRNA-3705 – This medication is administered intravenously and is currently being studied in clinical trials for its safety, tolerability, and effectiveness. It is specifically designed for individuals with isolated Methylmalonic Acidemia due to Methylmalonyl-CoA Mutase Deficiency. The medication works by delivering synthetic messenger RNA (mRNA) to cells, which instructs them to produce the deficient enzyme, potentially correcting the metabolic disorder. mRNA-3705 falls under the pharmacological classification of gene therapy products.

Investigated diseases

Isolated Methylmalonic Acidemia Due to Methylmalonyl-CoA Mutase Deficiency – This is a rare genetic disorder that affects the body's ability to break down certain fats and proteins. It is caused by a deficiency in the enzyme methylmalonyl-CoA mutase, which leads to the accumulation of methylmalonic acid in the blood. This buildup can cause a variety of symptoms, including developmental delays, feeding difficulties, and lethargy. Over time, individuals may experience episodes of metabolic decompensation, which can lead to more severe symptoms. The condition is typically diagnosed in infancy or early childhood. Management focuses on dietary modifications and monitoring to prevent metabolic crises.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase I/IITrial ID2022-502492-32-00Protocol codemRNA-3705-P101Estimated enrolment63 patientsSponsorModerna Inc.

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