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Last update 02 Jun 2026
L-9LS
Last update 02 Jun 2026
Overview
Basic Info
Drug Type Monoclonal antibody |
Synonyms VRC-MALMAB0114-00-AB, L-9LS |
Target |
Action inhibitors |
Mechanism PfCSP inhibitors(Plasmodium falciparum circumsporozoite protein inhibitors) |
Therapeutic Areas |
Active Indication |
Inactive Indication- |
Originator Organization |
Active Organization |
Inactive Organization- |
License Organization- |
Drug Highest PhasePhase 2 |
First Approval Date- |
Regulation- |
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Related
9
Clinical Trials associated with L-9LSNCT07208760
A Phase 2, Randomized, Double-Blind, Placebo-Controlled Trial to Evaluate the Effect of L9LS on R21/Matrix-M™ Vaccine Immunogenicity
This is a randomized, double-blind, placebo-controlled trial in 2 parts evaluating the effect of 1-time administration of the monoclonal antibody (MAb) L9LS to healthy Malian participants on the immunogenicity of subsequent administration of the R21/Matrix-M™ vaccine. L9LS will be administered subcutaneously (SC) for adults and infants. The study will assess how the timing of L9LS administration impacts immunogenicity following subsequent intramuscular (IM) R21/Matrix-M™ vaccination. Twenty-four adult participants and 333 infant participants will be enrolled.
Start Date01 Mar 2026 |
Sponsor / Collaborator |
NCT07060508
Safety and Efficacy of L9LS, a Human Monoclonal Antibody Against Plasmodium Falciparum, in a Randomized, Double-Blind, Placebo-Controlled Trial of Women of Childbearing Potential (WOCBP) in Mali
Safety and Efficacy of L9LS, a Human Monoclonal Antibody Against Plasmodium falciparum, in a Randomized, Double-Blind, Placebo-Controlled Trial of Women of Childbearing Potential (WOCBP) in Mali
Start Date22 Jul 2025 |
Sponsor / Collaborator |
PACTR202410517100221
A Phase 2, Randomized, Double-Blind, Placebo-Controlled Trial to Assess the Safety, Tolerability, and Efficacy of the Anti-Malaria Monoclonal Antibody L9LS in Infants 10 Weeks of Age in Western Kenya and to Evaluate the Impact of L9LS on Subsequent Malaria Vaccine Immunogenicity
Start Date02 Dec 2024 |
Sponsor / Collaborator- |
100 Clinical Results associated with L-9LS
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100 Translational Medicine associated with L-9LS
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100 Patents (Medical) associated with L-9LS
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4
Literatures (Medical) associated with L-9LS01 Apr 2026·LANCET
Safety and efficacy of the monoclonal antibody L9LS for malaria prevention in children exposed to perennial malaria transmission in Kenya: a randomised, double-blind, placebo-controlled, phase 2 trial
Article
BACKGROUND:
Malaria remains a major cause of mortality globally, especially among young children in sub-Saharan Africa. The long-acting monoclonal antibody L9LS has shown high efficacy in preventing malaria in children aged 6-10 years exposed to seasonal transmission but remains untested in perennial transmission settings and younger children. We assessed the safety, tolerability, and efficacy of L9LS in infants and children in a high perennial malaria transmission setting.
METHODS:
This double-blind, two-part, randomised, placebo-controlled, phase 2 trial was done in Siaya county in western Kenya. In parts 1a and 1b, we tested the safety and tolerability of L9LS using an age de-escalation and dose escalation approach and randomly assigned (3:1) cohorts of healthy children (three cohorts aged 5-10 years, three cohorts aged 5-59 months, and two cohorts aged 5-71 months) to L9LS at doses of 5, 10, 20, 30, or 40 mg/kg subcutaneously or to placebo (normal saline). In part 2, healthy children aged 5-59 months were randomly assigned (1:1:1) by use of centralised computer-generated lists to receive two doses of L9LS at 10-20 mg/kg at baseline and month 6, one dose of L9LS at baseline and placebo at month 6, or placebo at both timepoints. Children were followed up for 12 months with monthly clinic visits and blood smear collections. Primary safety outcomes were incidence and severity of local and systemic solicited adverse events within 7 days of dosing and serious adverse events throughout follow-up. The primary efficacy endpoint was Plasmodium falciparum infection detected by blood smear over 12 months. Primary analyses were done in the modified intention-to-treat population, consisting of all randomly assigned participants who received the study intervention. This trial is registered with ClinicalTrials.gov (NCT05400655) and is complete.
FINDINGS:
In parts 1a and 1b, 96 children were enrolled and randomly assigned between Oct 1, 2022, and Jan 16, 2024; 72 participants were assigned to L9LS and 24 were assigned to placebo. In part 2, 324 children aged 5-59 months were enrolled and randomly assigned between Jan 26 and June 2, 2023; 108 children were assigned to one-dose L9LS, 106 to two-dose L9LS, and 110 to placebo. Across all study parts, grade 3 or worse treatment-related adverse events occurred after four (1%) of 384 L9LS injections and two (1%) of 338 placebo injections; these events all resolved by study end. The proportion of solicited and unsolicited adverse events was similar across all L9LS dose groups. There were no serious adverse events related to the trial. In part 2, 70 (66%) of 106 children in the two-dose L9LS group had at least one P falciparum infection during the 12-month follow-up versus 91 (83%) of 110 children in the placebo group (protective efficacy 42·7%, 95% CI 22·5-57·7; p=0·0003).
INTERPRETATION:
L9LS was protective against malaria in young children in western Kenya without evident safety concerns over 6-12 months. A higher dose of L9LS might be needed to achieve high-level efficacy against malaria in young children exposed to intense perennial P falciparum transmission.
FUNDING:
Gates Foundation.
23 Apr 2025·Science Translational Medicine
FcγR binding differentially contributes to protection by two human monoclonal antibodies targeting
Plasmodium falciparum
circumsporozoite protein
Article
Author: Chakraborty, Saborni ; Wang, Taia T. ; Alter, Galit ; Pierson, Theodore C. ; Seder, Robert A. ; Asokan, Mangaiarkarasi ; Kiyuka, Patience ; Flynn, Barbara ; Zur, Yonatan ; Ogwang, Rodney ; Dillon, Marlon ; Flores-Garcia, Yevel ; Koup, Richard A. ; MacVicar, Ryan ; Ernste, Keenan ; Herman, Jonathan D. ; Liu, Cuiping ; Idris, Azza H. ; Zavala, Fidel ; Silva Pereira, Lais D. ; DeMouth, Megan E. ; Bonilla, Brian ; Francica, Joseph ; Kisalu, Neville K. ; Nikolaeva, Daria ; Lofgren, Mariah ; Pegu, Amarendra ; Merriam, Jonah
Antibodies mediate protection against a wide range of pathogens through binding and neutralizing the pathogen or through Fc-mediated effector functions. Human monoclonal antibodies (mAbs) CIS43LS and L9LS show high-affinity binding targeting distinct regions on the
Plasmodium falciparum
circumsporozoite protein (PfCSP) and are highly effective in preventing malaria in humans. However, the role of FcγR binding in protection by these mAbs has not been determined. Here, we assessed several Fc variants of CIS43LS and L9LS for protection against infection with transgenic
Plasmodium berghei
parasite expressing PfCSP in mice. Limiting binding to FcγRs did not reduce protection compared to the parental mAbs in mice. To determine whether protection could be improved in vivo by Fc modification, we engineered Fc variant mAbs with increased binding to distinct FcγRs. Passive transfer of CIS43LS-DE and CIS43LS-DEAL variants resulted in an approximately two- to threefold reduction in the liver-stage parasite burden in C57BL/6 or human FcγR mice compared with the parental CIS43LS after challenge. CIS43LS-DEAL also enhanced protection of mice after mosquito bite challenge. Systems serology analysis revealed that the CIS43LS-DE and CIS43LS-DEAL variants could enhance human neutrophil and monocyte phagocytosis, as well as NK cell activation, compared with CIS43LS. However, similar Fc modifications incorporated into L9LS did not increase protection compared to the parental mAb. Overall, although FcγR binding by CIS43LS and L9LS is dispensable in mouse models of malaria, enhancing the binding of CIS43LS to FcγR showed a modest increase in the potency of this mAb.
02 May 2024·The New England journal of medicine
Subcutaneous Administration of a Monoclonal Antibody to Prevent Malaria
Article
Author: Traore, Hamadi ; McDermott, Adrian B ; Narpala, Sandeep ; Reiber, Matthew ; Portugal, Silvia ; Lin, Bob C ; Keita, Mamadou ; Peterson, Mary E ; Idris, Azza H ; Carlton, Kevin ; Traore, Siriman ; Hu, Zonghui ; Hickman, Somia P ; Doumbo, Safiatou ; McDougal, Andrew J ; Stein, Judy A ; Ouattara, Adama ; Zéguimé, Amatigué ; Seder, Robert A ; Wang, Jing ; Murphy, Sean C ; Ongoiba, Aissata ; Doucoure, M'Bouye ; Schwabl, Philipp ; Serebryannyy, Leonid ; Djimdé, Abdoulaye ; Li, Shanping ; Kayentao, Kassoum ; Djiguiba, Adama ; Dolo, Amagana ; Neafsey, Daniel E ; Crompton, Peter D ; Cisse, Hamidou ; Vazquez, Sandra ; Healy, Sara A ; Traore, Boubacar ; Traore, Abdrahamane ; Preston, Anne C ; Telscher, Shinyi ; Skinner, Jeff ; Doumtabe, Didier ; Gall, Jason G ; Adams, William C
BACKGROUND:
Subcutaneous administration of the monoclonal antibody L9LS protected adults against controlled Plasmodium falciparum infection in a phase 1 trial. Whether a monoclonal antibody administered subcutaneously can protect children from P. falciparum infection in a region where this organism is endemic is unclear.
METHODS:
We conducted a phase 2 trial in Mali to assess the safety and efficacy of subcutaneous administration of L9LS in children 6 to 10 years of age over a 6-month malaria season. In part A of the trial, safety was assessed at three dose levels in adults, followed by assessment at two dose levels in children. In part B of the trial, children were randomly assigned, in a 1:1:1 ratio, to receive 150 mg of L9LS, 300 mg of L9LS, or placebo. The primary efficacy end point, assessed in a time-to-event analysis, was the first P. falciparum infection, as detected on blood smear performed at least every 2 weeks for 24 weeks. A secondary efficacy end point was the first episode of clinical malaria, as assessed in a time-to-event analysis.
RESULTS:
No safety concerns were identified in the dose-escalation part of the trial (part A). In part B, 225 children underwent randomization, with 75 children assigned to each group. No safety concerns were identified in part B. P. falciparum infection occurred in 36 participants (48%) in the 150-mg group, in 30 (40%) in the 300-mg group, and in 61 (81%) in the placebo group. The efficacy of L9LS against P. falciparum infection, as compared with placebo, was 66% (adjusted confidence interval [95% CI], 45 to 79) with the 150-mg dose and 70% (adjusted 95% CI, 50 to 82) with the 300-mg dose (P<0.001 for both comparisons). Efficacy against clinical malaria was 67% (adjusted 95% CI, 39 to 82) with the 150-mg dose and 77% (adjusted 95% CI, 55 to 89) with the 300-mg dose (P<0.001 for both comparisons).
CONCLUSIONS:
Subcutaneous administration of L9LS to children was protective against P. falciparum infection and clinical malaria over a period of 6 months. (Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT05304611.).
3
News (Medical) associated with L-9LS09 May 2024
PASADENA, Calif.--(BUSINESS WIRE)-- Xencor, Inc. (NASDAQ:XNCR), a clinical-stage biopharmaceutical company developing engineered antibodies for the treatment of cancer and other serious diseases, today reported financial results for the first quarter ended March 31, 2024 and provided a review of recent clinical and business highlights.
“We have focused our XmAb® clinical pipeline and discovery activities on bispecific CD3 and CD28 T cell engagers, which continue to show clinical validation for their potential in treating patients with serious diseases. Our key clinical-stage oncology programs in solid tumors include XmAb819 (ENPP3 x CD3) in clear cell renal cell carcinoma, XmAb808 (B7-H3 x CD28) in prostate cancer and other cancers, and XmAb541 (CLDN6 x CD3) in ovarian cancer and other cancers, which are all now advancing in Phase 1 clinical studies. We plan to select our next T cell engager IND candidate later this year,” said Bassil Dahiyat, Ph.D., president and chief executive officer at Xencor. “Additionally, Xencor’s best-in-class Xtend™ antibody half-life extension technology continues to support improved outcomes for patients, with Ultomiris® now approved in the U.S. for certain patients with NMOSD, and we are especially delighted by recently published results demonstrating an investigational antibody with Xtend was effective in preventing malaria.”
Recent Clinical and Business Highlights
First Patient Dosed in Phase 1 Study of XmAb®541 (CLDN6 x CD3): XmAb541 is a bispecific antibody being developed for patients with CLDN6-positive tumors including advanced ovarian cancer. XmAb541 is designed to engage the immune system, activating T cells for highly potent and targeted killing of tumor cells expressing Claudin-6 (CLDN6), a tumor-associated antigen. Xencor’s XmAb® 2+1 multivalent format used in XmAb541 enables greater selectivity for cells expressing CLDN6 over similarly structured Claudin family members, which may be expressed on normal tissue. The first patient was recently dosed in a Phase 1 dose-escalation study.
FDA Approves Ultomiris® (Alexion Pharmaceuticals, Inc.) for Adults with NMOSD: In March 2024, Ultomiris® (ravulizumab-cwvz), which incorporates Xencor’s Xtend™ Fc Domain, was approved in the United States as the first and only long-acting C5 complement inhibitor for the treatment of adult patients with anti-aquaporin-4 (AQP4) antibody-positive (Ab+) neuromyelitis optica spectrum disorder (NMOSD). Ultomiris is also approved for certain adults with NMOSD in Japan and the European Union (EU). As part of Xencor’s recent Ultomiris royalty monetization, the Company remains eligible for certain future royalties and milestone payments. Ultomiris is a registered trademark of Alexion Pharmaceuticals, Inc.
Single Dose of Investigational Antibody with Xtend™ Confers Protection Against Malaria Infection: Results from a Phase 2 National Institutes of Health (NIH)-sponsored clinical trial published in the New England Journal of Medicine showed that a single dose of L9LS, an experimental monoclonal antibody that incorporates Xencor’s Xtend™ Fc Domain, was up to 77% effective in preventing malaria in children in Mali for six months, demonstrating the long duration of action that Xtend technology can provide.
New Chief Financial Officer Appointed: Bart Cornelissen was appointed as Xencor’s senior vice president and chief financial officer. He was most recently vice president, corporate finance at Seagen Inc.
Financial Guidance: Based on current operating plans, Xencor expects to end 2024 with between $475 million and $525 million in cash, cash equivalents and marketable debt securities, and to have cash to fund research and development programs and operations into 2027.
Financial Results for the First Quarter Ended March 31, 2024
Cash, cash equivalents and marketable debt securities totaled $646.7 million as of March 31, 2024, compared to $697.4 million on December 31, 2023.
Revenues for the first quarter ended March 31, 2024 were $12.8 million, compared to $19.0 million for the same period in 2023. Total revenues earned in the first quarter of 2024 included non-cash royalty revenue from Xencor’s Alexion and Morphosys/Incyte agreements, compared to milestone revenue earned from the J&J collaboration and royalties from the Alexion agreement in the first quarter of 2023.
Research and development expenses for the first quarter ended March 31, 2024 were $56.9 million, compared to $65.6 million for the same period in 2023. Decreased research and development spending for the first quarter of 2024 compared to 2023 reflects changes in spending across multiple clinical-stage programs and wind-down costs on terminated programs.
General and administrative expenses for the first quarter ended March 31, 2024 were $13.8 million and were in line with $14.2 million for the same period in 2023.
Other expense, net, for the first quarter ended March 31, 2024 was $10.8 million, compared to $0.02 million for the same period in 2023. Increased other expense for the first quarter of 2024 compared to 2023 reflects impairment charge on equity investments, partially offset by interest income earned on investments and unrealized gain on equity investments.
Non-cash, stock-based compensation expense for the first quarter ended March 31, 2024 was $11.4 million, compared to $12.6 million for the same period in 2023.
Net loss for the first quarter ended March 31, 2024 was $68.0 million, or $(1.11) on a fully diluted per share basis, compared to $60.8 million, or $(1.02) on a fully diluted per share basis, for the same period in 2023.
The total shares outstanding were 61,634,685 as of March 31, 2024, compared to 60,381,600 as of March 31, 2023.
Upcoming Investor Conferences
Company management will participate at multiple upcoming investor conferences:
RBC Capital Markets Global Healthcare Conference
Date: Tuesday, May 14, 2024
Presentation Time: 2:05 p.m. ET / 11:05 a.m. PT
Location: New York City
BofA Securities Health Care Conference
Date: Wednesday, May 15, 2024
Presentation Time: 4:40 p.m. ET / 1:40 p.m. PT
Location: Las Vegas
Live webcasts of the presentations will be available under “Events & Presentations” in the Investors section of the Company’s website located at . Replays of the events will be available on the Xencor website for at least 30 days following the presentations.
About Xencor
Xencor is a clinical-stage biopharmaceutical company developing engineered antibodies for the treatment of patients with cancer and other serious diseases. More than 20 candidates engineered with Xencor's XmAb® technology are in clinical development, and three XmAb medicines are marketed by partners. Xencor's XmAb engineering technology enables small changes to a proteins structure that result in new mechanisms of therapeutic action. For more information, please visit .
Forward-Looking Statements
Certain statements contained in this press release may constitute forward-looking statements within the meaning of applicable securities laws. Forward-looking statements include statements that are not purely statements of historical fact, and can generally be identified by the use of words such as “potential,” “can,” “will,” “plan,” “may,” “could,” “would,” “expect,” “anticipate,” “seek,” “look forward,” “believe,” “committed,” “investigational,” and similar terms, or by express or implied discussions relating to Xencor’s business, including, but not limited to, statements regarding planned presentations of clinical data, planned clinical trials, projected financial resources, the quotations from Xencor's president and chief executive officer, and other statements that are not purely statements of historical fact. Such statements are made on the basis of the current beliefs, expectations, and assumptions of the management of Xencor and are subject to significant known and unknown risks, uncertainties and other factors that may cause actual results, performance or achievements and the timing of events to be materially different from those implied by such statements, and therefore these statements should not be read as guarantees of future performance or results. Such risks include, without limitation, the risks associated with the process of discovering, developing, manufacturing and commercializing drugs that are safe and effective for use as human therapeutics and other risks, including the ability of publicly disclosed preliminary clinical trial data to support continued clinical development and regulatory approval for specific treatments, in each case as described in Xencor's public securities filings. For a discussion of these and other factors, please refer to Xencor's annual report on Form 10-K for the year ended December 31, 2023 as well as Xencor's subsequent filings with the Securities and Exchange Commission. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. This caution is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995, as amended to date. All forward-looking statements are qualified in their entirety by this cautionary statement and Xencor undertakes no obligation to revise or update this press release to reflect events or circumstances after the date hereof, except as required by law.
Xencor, Inc.
Selected Consolidated Balance Sheet Data
(in thousands)
March 31,
December 31,
2024
2023
(Unaudited)
Cash, cash equivalents and marketable debt securities - current
$
491,401
$
551,515
Other current assets
70,851
71,645
Marketable debt securities - long term
155,342
145,892
Other long term assets
166,661
183,640
Total assets
$
884,255
$
952,692
Total current liabilities
79,402
84,709
Deferred income - long term
113,367
125,183
Other long term liabilities
79,299
73,667
Total liabilities
272,068
283,559
Total stockholders' equity
612,187
669,133
Total liabilities and stockholders’ equity
$
884,255
$
952,692
Xencor, Inc.
Consolidated Statements of Loss and Comprehensive Loss
(in thousands, except share and per share data)
Three months Ended March 31,
2024
2023
(Unaudited)
Revenue
$
12,805
$
18,962
Operating expenses
Research and development
56,873
65,552
General and administrative
13,787
14,154
Total operating expenses
70,660
79,706
Loss from operations
(57,855
)
(60,744
)
Other income (expense), net
(10,854
)
(19
)
Loss before income tax
(68,709
)
(60,763
)
Income tax expense
—
—
Net loss
(68,709
)
(60,763
)
Net loss attributable to non-controlling interest
(676
)
—
Net loss attributable to Xencor, Inc.
(68,033
)
(60,763
)
Other comprehensive income (loss):
Net unrealized gain (loss) on marketable debt securities available-for-sale
(1,445
)
3,327
Comprehensive loss attributable to Xencor, Inc.
$
(69,478
)
$
(57,436
)
Net loss per common share attributable to Xencor, Inc.:
Basic and Diluted
$
(1.11
)
$
(1.02
)
Weighted average common shares used to compute net loss per share attributable to Xencor, Inc.
Basic and Diluted
61,212,324
59,771,674
Phase 1Phase 2Drug ApprovalClinical ResultFinancial Statement
01 Nov 2022
One dose of an antibody drug safely protected healthy, non-pregnant adults from malaria infection during an intense six-month malaria season in Mali, Africa, a National Institutes of Health clinical trial has found. The antibody was up to 88.2% effective at preventing infection over a 24-week period, demonstrating for the first time that a monoclonal antibody can prevent malaria infection in an endemic region.
One dose of an antibody drug safely protected healthy, non-pregnant adults from malaria infection during an intense six-month malaria season in Mali, Africa, a National Institutes of Health clinical trial has found. The antibody was up to 88.2% effective at preventing infection over a 24-week period, demonstrating for the first time that a monoclonal antibody can prevent malaria infection in an endemic region. These findings were published today in The New England Journal of Medicine and presented at the American Society of Tropical Medicine & Hygiene 2022 Annual Meeting in Seattle.
"We need to expand the arsenal of available interventions to prevent malaria infection and accelerate efforts to eliminate the disease," said Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID), part of NIH. "These study results suggest that a monoclonal antibody could potentially complement other measures to protect travelers and vulnerable groups such as infants, children, and pregnant women from seasonal malaria and help eliminate malaria from defined geographical areas."
NIAID sponsored and funded the trial, which was led by Peter D. Crompton, M.D., M.P.H., and Kassoum Kayentao, M.D., M.P.H., Ph.D. Dr. Crompton is chief of the Malaria Infection Biology and Immunity Section in the NIAID Laboratory of Immunogenetics, and Dr. Kayentao is a professor at the University of Sciences, Techniques and Technologies (USTTB) of Bamako, Mali.
An estimated 241 million cases of malaria occurred worldwide in 2020, according to the World Health Organization (WHO), resulting in an estimated 627,000 deaths, mostly in children in sub-Saharan Africa. These cases included more than 11 million pregnant women in Africa, resulting in an estimated 819,000 newborns with low birthweight and thus at increased risk for illness and death.
The only malaria vaccine currently recommended by WHO, called RTS,S (Mosquirix), provides partial protection against clinical malaria during the early years of life when given to children aged 5 to 17 months in four doses over a 20-month period. Other drugs consisting of small chemical compounds that effectively prevent malaria infection are also available for infants and young children as well as travelers. The requirement for frequent dosing of these drugs can limit adherence, however, and the emergence of drug resistance may also limit their usefulness. Thus, there is an urgent need for new, fast-acting, infrequently dosed interventions that safely provide strong protection against malaria infection.
Malaria is caused by Plasmodium parasites, which are transmitted to people through the bite of an infected mosquito. The mosquito injects the parasites in a form called sporozoites into the skin and bloodstream. These travel to the liver, where they mature and multiply. Then the mature parasite spreads throughout the body via the bloodstream to cause illness. P. falciparum is the Plasmodium species most likely to result in severe malaria infections, which, if not promptly treated, may lead to death.
The Phase 2 NIAID-USTTB trial evaluated the safety and efficacy of a one-time, intravenous infusion of a monoclonal antibody called CIS43LS. This antibody was previously shown to neutralize the sporozoites of P. falciparum in the skin and blood before they could infect liver cells. Researchers led by Robert A. Seder, M.D., isolated a naturally occurring form of this antibody from the blood of a volunteer who had received an investigational malaria vaccine, and then modified the antibody to extend the length of time it would remain in the bloodstream. Dr. Seder is the acting chief medical officer and acting associate director of the NIAID Vaccine Research Center (VRC) and chief of the VRC's Cellular Immunology Section.
The study team for the Phase 2 trial enrolled 369 healthy, non-pregnant adults aged 18 to 55 years in the rural communities of Kalifabougou and Torodo in Mali, where intense P. falciparum transmission typically occurs from July through December each year.
The first part of the trial assessed the safety of three different doses of CIS43LS -- 5 milligrams per kilogram of body weight, 10 mg/kg and 40 mg/kg -- administered by intravenous infusion in 18 study participants, with six participants per dose level. The study team followed these participants for 24 weeks and found the antibody infusions were safe and well-tolerated.
The second part of the trial assessed the efficacy of two different doses of CIS43LS compared to a placebo. Three hundred and thirty participants were assigned at random to receive either 10 mg/kg of the antibody, 40 mg/kg, or a placebo by intravenous infusion. No one knew who was assigned to which group until the end of the trial. The study team followed these individuals for 24 weeks, testing their blood for P. falciparum weekly for the first 28 days and every two weeks thereafter. Any participant who developed symptomatic malaria during the trial received standard treatment from the study team.
The investigators analyzed the efficacy of CIS43LS two ways. Based on the time to first P. falciparum infection over the 24-week study period, the high dose (40 mg/kg) of CIS43LS was 88.2% effective at preventing infection and the lower dose (10 mg/kg) was 75% effective. An analysis of the proportion of participants infected with P. falciparum at any time over the 24-week study period found the high dose was 76.7% at preventing infection and the lower dose was 54.2% effective.
"These first field results demonstrating that a monoclonal antibody safely provides high-level protection against intense malaria transmission in healthy adults pave the way for further studies to determine if such an intervention can prevent malaria infection in infants, children, and pregnant women," Dr. Seder said. "We hope monoclonal antibodies will transform malaria prevention in endemic regions."
Dr. Seder and colleagues have developed a second antimalarial monoclonal antibody, L9LS, that is much more potent than CIS43LS and therefore can be administered in a smaller dose as an injection under the skin (subcutaneously), rather than by intravenous infusion. An early-phase NIAID trial of L9LS in the United States found that the antibody was safe and prevented malaria infection for 21 days in 15 out of 17 healthy adults exposed to P. falciparum in a carefully controlled setting. Two larger, NIAID-sponsored Phase 2 trials assessing the safety and efficacy of L9LS in infants, children and adults are underway in Mali and Kenya.
Additional information about the Phase 2 trial of CIS43LS is available at ClinicalTrials.gov under study identifier NCT04329104.
AntibodyVaccine
04 Aug 2022
One injection of a candidate monoclonal antibody (mAb) known as L9LS was found to be safe and highly protective in U.S. adults exposed to the malaria parasite, according to new results. Additional clinical trials evaluating if L9LS can prevent malaria over six to 12 months against seasonal and perennial transmission are underway in infants and children in Mali and Kenya, where malaria is endemic.
One injection of a candidate monoclonal antibody (mAb) known as L9LS was found to be safe and highly protective in U.S. adults exposed to the malaria parasite, according to results from a National Institutes of Health Phase 1 clinical trial published in The New England Journal of Medicine. Additional clinical trials evaluating if L9LS can prevent malaria over six to 12 months against seasonal and perennial transmission are underway in infants and children in Mali and Kenya, where malaria is endemic. The trial was sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), part of NIH.
"These early clinical trial results demonstrating that a monoclonal antibody administered subcutaneously can protect people from malaria are highly encouraging," said NIAID Director Anthony S. Fauci, M.D. "A one-time intervention that protects against malaria for six months to a year could significantly reduce morbidity and mortality among children in malaria-endemic regions and offer an effective preventive tool for health care workers, military personnel and travelers to these areas."
Malaria is a mosquito-borne disease caused by Plasmodium parasites. The World Health Organization estimates that in 2020, about 240 million people had malaria and about 627,000 of them died. A disproportionate burden of malarial disease is seen in Sub-Saharan Africa, where children under age 5 account for approximately 80% of all malaria deaths. A vaccine to prevent malaria is now available; however, its variable efficacy underscores the need for new interventions that offer high-level protection against disease.
Scientists from NIH's Vaccine Research Center (VRC), part of NIAID, developed L9LS and led the Phase 1 clinical trial. L9LS is a laboratory-made version of a naturally occurring antibody called L9, derived from the blood of a volunteer who had received an investigational malaria vaccine. The antibody prevents malaria by neutralizing the parasites in the skin and blood before they can infect liver cells.
L9LS is similar to a candidate anti-malarial antibody known as CIS43LS that the VRC developed and found to be highly protective in a small trial when administered by the intravenous route. However, L9LS is two to three times more potent. Increasing the potency allowed for subcutaneous injection, a more cost-effective and feasible route of administration than intravenous infusion.
The Phase 1 study was conducted from Sept. 13 to Nov. 16, 2021, at the NIH Clinical Center in Bethesda, Maryland, and the Walter Reed Army Institute of Research (WRAIR) in Silver Spring, Maryland. The trial involved 18 volunteer participants receiving various doses of L9LS subcutaneously or intravenously. After tolerating the injection and experiencing no safety concerns, the participants allowed mosquitoes carrying the malaria parasite to bite their forearm five times, starting from two to six weeks after receiving the mAb candidate. This took place in a carefully controlled setting, known as controlled human malaria infection (CHMI). As part of this approach, which has been used for decades in malaria research, medical staffers closely monitor participants and provide proper treatment if they become infected. L9LS fully protected 15 of 17 (88%) participants from malaria infection during the 21-day challenge period. All volunteers in the control group that underwent CHMI, but did not receive L9LS, became infected and were promptly treated without complications. Encouragingly, four of the five participants who received a low, subcutaneous dose of the mAb were protected from malaria.
"This is the first demonstration that a monoclonal antibody can provide protection when given by the subcutaneous route, with important implications for widespread clinical use and reaching the goal of eliminating malaria," said Robert Seder, M.D., chief of the Cellular Immunology Section in the VRC, who led the development of L9LS. "We look forward to results in larger field studies that will help establish an effective dose."
Lt. Cmdr. Richard Wu, M.D., staff clinician in the VRC's Clinical Trials Program, led the Phase 1 trial. Study collaborators included scientists from the U.S. Public Health Service Commissioned Corps; the Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University; NIAID'S Biostatistics Research Branch; WRAIR; and the University of California at San Diego.
VaccineAntibody
100 Deals associated with L-9LS
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| Indication | Highest Phase | Country/Location | Organization | Date |
|---|---|---|---|---|
| Malaria | Phase 2 | Mali | 18 Mar 2022 |
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Clinical Result
Clinical Result
Indication
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| Study | Phase | Population | Analyzed Enrollment | Group | Results | Evaluation | Publication Date |
|---|
Phase 2 | 384 | two-dose L9LS | vxweayjdxn(iowatuvrsp) = grade 3 or worse treatment-related adverse events occurred after four (1%) of 384 L9LS injections and two (1%) of 338 placebo injections; these events all resolved by study end dzblyaeqso (tudafvcgqx ) View more | Positive | 01 Apr 2026 | ||
Placebo | |||||||
Phase 2 | 490 | (L9LS 900 mg) | aolpfobzog = awdokgaunw swazsfmluz (fmtmxykgkw, hmwesfxrty - wojxuprmco) View more | - | 02 Apr 2025 | ||
Placebo (Placebo) | aolpfobzog = wdbsonhfcq swazsfmluz (fmtmxykgkw, dzmvedhikl - wavshtymqg) View more | ||||||
NCT05304611 (Pubmed) Manual  | Phase 2 | 225 | naivugutbw(jnisebikdj) = qxfnqjfwdc fproakwfli (pvskuehcnm ) View more | Positive | 26 Apr 2024 | ||
naivugutbw(jnisebikdj) = evqlzoxnvg fproakwfli (pvskuehcnm ) View more | |||||||
Phase 1 | 32 | Plasmodium falciparum (P. falciparum) sporozoite challenge+VRC-MALMAB0114-00-AB (Group 1: L9LS (1 mg/kg IV)) | olsjyjtvfv = gdrbegnocf gbcnfqgiiq (esnwpclnbx, brwjtwjdbb - fixouqtjms) View more | - | 13 Oct 2023 | ||
Plasmodium falciparum (P. falciparum) sporozoite challenge+VRC-MALMAB0114-00-AB (Group 2: L9LS (5 mg/kg IV)) | olsjyjtvfv = gqbqsyrslg gbcnfqgiiq (esnwpclnbx, nljjxtxvtw - cgaoexjwwk) View more |
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