Updated May 2026 · ClinicalTrials.gov
Safety, Tolerability and Efficacy Against Controlled Human Malaria Infection of PfSPZ-LARC2 Vaccine in Malaria-naïve Adults
Safety, Tolerability and Efficacy Against Controlled Human Malaria Infection of PfSPZ-LARC2 Vaccine in Malaria-naïve Adults (NCT06862453) is a Phase 1 interventional studying Malaria Falciparum, sponsored by Sanaria Inc.. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.
About This Trial
This is a first-in-human, randomized, double-blind, placebo-controlled Phase 1 trial of Plasmodium falciparum (Pf) sporozoite (SPZ) late-arresting replication-competent (LARC) malaria vaccine (PfSPZ-LARC2 Vaccine) administered to healthy, malaria-naive study participants in Germany by direct venous inoculation (DVI) to determine safety, tolerability, and vaccine efficacy (VE) against controlled human malaria infection (CHMI). PfSPZ-LARC2 Vaccine contains a deletion of two genes, the Mei2 and LINUP genes, and undergoes developmental arrest in the late liver stages without releasing merozoites into the blood stream (blood stage parasites). The primary objective of the study is to assess the safety and tolerability of administration of PfSPZ-LARC2 Vaccine, with special attention to the adequacy of attenuation, in the intention-to-treat (ITT) population. Studies of PfSPZ-LARC2 in FRG mice indicate that Plasmodium falciparum LARC2 parasites halt development in their late liver life cycle stages and do not generate viable merozoites able to initiate blood stage infection. Attenuation in this assay system has been a good predictor of attenuation in humans, indicating that blood stage infection in this trial of PfSPZ-LARC2 Vaccine will not occur. Recent data from Leiden University where a Mei2 single deletion parasite was administered to human participants by mosquito bite confirmed that removing this single gene by itself confers complete attenuation. PfSPZ-LARC2 Vaccine has both Mei2 and LINUP deleted, so it should be completely attenuated. In order to better understand what side effects might look like, on the small chance that PfSPZ-LARC2 Vaccine is not adequately attenuated, it is important to briefly describe the safety data from studies of PfSPZ-CVac (chloroquine), a whole Plasmodium falciparum sporozoite (PfSPZ) immunization approach that uses cGMP produced, aseptic, purified, cryopreserved, non-attenuated, fully infectious PfSPZ administered under chloroquine cover. This is because the safety and tolerability data from PfSPZ-CVac represent a worst case scenario for what could happen with PfSPZ-LARC2 Vaccine with respect to safety and tolerability, as recipients of PfSPZ-CVac always have blood stage infection after the first immunization, even if small doses are administered. The current standard regimen in malaria-naive adults receiving PfSPZ-CVac is 2.0x10\^5 PfSPZ, 62.5-fold higher than the 100% infective dose for controlled human malaria infection (CHMI) in malaria-naive individuals, which is 3.2x10\^3 PfSPZ. The blood stage infection is detectable by ultrasensitive qPCR on days 7 to 9 after PfSPZ administration and then clears due to the schizonticidal action of chloroquine. Doses used for PfSPZ-CVac have been escalated to as high as 2x10\^5 PfSPZ in malaria-naive adults and 4.0x10\^5 PfSPZ in malaria-exposed adults, and are generally well tolerated; however, some individuals experienced symptoms of malaria on days 7 and 8 during the period of transient parasitemia, including Grade 3 adverse events, which can largely be prevented by the administration of drugs such as ibuprofen, naproxen or acetaminophen starting the morning of day 7 or after symptoms appear. Once the first dose of 2x10\^5 PfSPZ is administered, immunity develops rapidly, and when the second and third doses are administered at 4-week intervals, there have been no Grade 3 adverse events recorded even in the absence of ibuprofen, naproxen or acetaminophen. These data from PfSPZ-CVac are relevant because they represent a possible worst-case scenario for PfSPZ-LARC2 Vaccine. In other words, even if the attenuation of PfSPZ-LARC2 parasites is not realized in vivo, the density of parasitemia should not be any higher nor the tolerability any worse than what has already been experienced with non-attenuated PfSPZ-CVac administered at the same PfSPZ dose. On the contrary, we would expect the percentage of participants with a blood stage infection to be lower following PfSPZ-LARC2 Vaccine administration due to its intrinsic attenuation than with non-attenuated PfSPZ, and in individuals with a blood stage infection, the numbers of parasites released from the liver to be lower than with non-attenuated PfSPZ. This will be the first assessment of PfSPZ-LARC2 Vaccine in humans. While we anticipate that vaccine efficacy (VE) in humans will be similar to that of PfSPZ-CVac, we have no data at this point, and it will be important to collect these comparative data. However, in the Leiden trial, where the Mei2 single knockout called GA2 was administered by mosquito bite, there was good protection after 3 immunizations by exposure to 50 infected mosquitoes (8/9 participants protected against homologous CHMI using 5 infected mosquitoes).
What Stage of Research Is This?
Phase 1 trials test a new treatment for the first time in humans, focusing on safety, dosing, and how the body processes the drug. For Malaria Falciparum, a Phase 1 study typically enrolls a small number of participants — often healthy volunteers or patients who have exhausted standard treatment options. Phase 1 results determine whether a treatment moves into larger Phase 2 efficacy studies.
This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.
Target enrollment of 58 participants puts this in the typical range for a Phase 2-style efficacy study or a moderate Phase 3 trial in a focused Malaria Falciparum subpopulation. At this scale, the study has enough statistical power to detect a clear treatment effect but is not the largest cohort in the field.
Who May Be Eligible (Plain English)
These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.
Original Eligibility Criteria
View original clinical language
Treatments Being Tested
Normal Saline (Placebo)
The blinded control group (n = 6) of the main cohort will receive normal saline as placebo, also by DVI.
PfSPZ-LARC2 Vaccine
Plasmodium falciparum (Pf) sporozoite (SPZ) late-arresting replication-competent (LARC) malaria vaccine (PfSPZ-LARC2 Vaccine) contains a deletion of two genes, the Mei2 and LINUP genes, and undergoes developmental arrest in the late liver stages without releasing merozoites into the blood stream (blood stage parasites).
PfSPZ Challenge (NF54)
Main cohort participants will undergo homologous CHMI using DVI of 3.2x10\^3 PfSPZ of PfSPZ Challenge (NF54), which are infectious cryopreserved Pf sporozoites.
Locations (1)
Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.
How to Talk to Your Doctor About This Trial
Bring the printable summary of this trial — including the NCT ID (NCT06862453), the sponsor (Sanaria Inc.), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.
Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.
Authoritative Sources
The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.
Frequently Asked Questions
What is the NCT06862453 clinical trial studying?
This is a first-in-human, randomized, double-blind, placebo-controlled Phase 1 trial of Plasmodium falciparum (Pf) sporozoite (SPZ) late-arresting replication-competent (LARC) malaria vaccine (PfSPZ-LARC2 Vaccine) administered to healthy, malaria-naive study participants in Germany by direct venous inoculation (DVI) to determine safety, tolerability, and vaccine efficacy (VE) against controlled human malaria infection (CHMI). PfSPZ-LARC2 Vaccine contains a deletion of two genes, the Mei2 and LINUP genes, and undergoes developmental arrest in the late liver stages without releasing merozoites i… The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.
Who can participate in NCT06862453?
Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.
How do I contact the trial site for NCT06862453?
Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.
Is participating in a clinical trial safe?
Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.
Where can I verify the data on this page?
Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.
How This Page Is Built
Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.
Source: ClinicalTrials.gov API v2 record for NCT06862453. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT06862453. Data: ClinicalTrials.gov."
Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.
Last updated 2026-05-08 · Data from ClinicalTrials.gov.