Longboard Pharmaceuticals : The Potential of LP352

Corporate Presentation - The Potential of LP352

December 2022

Forward-Looking Statements

This presentation contains forward-looking statements about Longboard Pharmaceuticals, Inc. ("we," "Longboard" or the "Company"), including statements regarding: our future results of operations and financial position; business strategy; the timing, costs, conduct and results of our preclinical studies and clinical trials for our product candidates, such as our expectations regarding our PACIFIC Study and data from our Phase 1 Open-Label PK/PD study; the timing and likelihood of regulatory filings and approvals for our product candidates, such as our pre-IND meeting for LP659; our intellectual property; our ability to obtain regulatory approval and commercialize our product candidates; the potential of LP352, including to limit adverse events associated with currently available non-selective ASMs, make a difference across a range of DEEs, and be a best-in-class ASM, including through BID dosing; and other statements that are not historical facts, including statements that may include words such as "will", "may", "can", "intend", "plan", "expect", "believe", "potential" and similar words.

For such statements, we claim the protection of the Private Securities Litigation Reform Act of 1995. These forward-looking statements are subject to a number of risks, uncertainties and assumptions, including, but not limited to: our limited operating history; net losses; our expectation that we will incur net losses for the foreseeable future, and that we may never be profitable; our need for additional funding and related risks for our business, product development programs and future commercialization activities; the timing and success of clinical trials we conduct; topline data may not reflect the complete or final results of a particular study or trial, and are subject to change; the ability to obtain and maintain regulatory approval of our product candidates; the ability to commercialize our product candidates; our ability to compete in the marketplace; risks regarding our license and dependencies on others; our ability to obtain and maintain intellectual property protection and freedom to operate for our product candidates; our ability to manage our growth; and other risks and factors disclosed in our filings with the U.S. Securities and Exchange Commission (the "SEC"). We operate in a very competitive and rapidly changing environment. New risks emerge from time to time. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. The forward-looking events and circumstances discussed in this presentation may not occur and actual results could differ materially and adversely from those anticipated or implied in the forward-looking statements. Except as required by law, we assume no responsibility for the accuracy and completeness of the forward-looking statements, and we undertake no obligation to update any forward-looking statements after the date of this presentation to conform these statements to actual results or to changes in our expectations.

Certain information contained in this presentation and statements made orally during this presentation relate to or are based on studies, research, publications, surveys and other data obtained from third-party sources and Longboard's own internal estimates and research. While Longboard believes these third-party studies, research, publications, surveys and other data to be reliable as of the date of this presentation, it has not been independently verified, and makes no representations as to the adequacy, fairness, accuracy or completeness of, any information obtained from third-party sources.

This presentation discusses product candidates that have not yet been approved for marketing by the U.S. Food and Drug Administration.

LONGBOARD PHARMACEUTICALS

2

Longboard's Pipeline of Next Generation GPCR Programs

Program	MOA	Therapeutic Area	Preclinical Ph I	Ph II	Ph III	Anticipated Milestones
						• Ph 1 data at medical mtg. -
						• H1 2022
LP352	5-HT2C	DEEs and other				• Ph 1 CSF PK/PD qEEG data -
Superagonist	refractory epilepsies				Q4 2022
						• Ph 1b/2a PACIFIC Study
						Data - H2 2023

LP659	S1P Receptor	Multiple neurological	• Pre-IND Meeting - Q4 2022
Modulator	diseases

• We hold rights to other product candidates, including LP143 and nelotanserin, through the Arena License Agreement
• We are eligible to receive royalties of 9.5% - 18.5% on sales of lorcaserin if approved for commercialization*

	* Through the Royalty Purchase Agreement
LONGBOARD PHARMACEUTICALS	Definitions: DEEs=developmental and epileptic encephalopathies; S1P = sphingosine 1-phosphate; PK=pharmacokinetics; PD=pharmacodynamics; EEG = electroencephalogram	3

LP352 has the Potential to Make a Difference Across a Range of DEEs

LP352

Greater Selectivity and

Specificity

The product of

20 years of world-class

GPCR research and

optimization

Penetrates the brain in a dose-dependent,

consistent and sustained manner

5-HT2proof-of-concept observed across multiple DEEs and seizures types, however there are safety and dosing considerations with other compounds:

• LP352 is the only 5-HT2C agonist being dose optimized to address this patient population

LP352 demonstrated predictive efficacy in several pre-clinical seizure models:

• Multiple zebrafish and rodent models

Demonstrated consistent CNS engagement through:

• Transient prolactin increases
• Sustained qEEG activity

Ph 1 data support potential best-in-class profile:

• SAD/MAD
• CSF/EEG

Enrolling the Ph 1b/2a PACIFIC study in patients 12-65 years old with DEE diagnosis

• No echocardiograms
• Evaluating broad range of seizure types across DEEs

Strong IP protection through 2041*

	*Composition of matter through 2036 with potential for PTE & PTA (2041)
LONGBOARD PHARMACEUTICALS	Definitions: DEEs=developmental and epileptic encephalopathies; CSF = cerebrospinal fluid;	4
EEG = electroencephalogram

The Potential of 5-HT2C Superagonist LP352

1. potential best-in-class serotonin receptor agonist anti- seizure product candidate that is designed to be highly selective and being dose-optimized to treat a broad range of DEEs effectively and safely