Clinical Development Programs

We build our pipeline by licensing or acquiring promising cancer agents and creating value in programs through development, commercialization and strategic partnerships, as appropriate. Our objective is to leverage the mechanisms and properties of our pipeline drug candidates to optimize the balance between efficacy and tolerability to meet the needs of patients with cancer. Our drug candidate pipeline includes:

Reduction in Force and Current Events

In November 2022, we and Kyowa Kirin Co., Ltd. ("KKC") met with the U.S. Food and Drug Administration ("FDA") in a follow-up meeting to the March 2022 end of Phase 2 meeting. At this meeting, the FDA provided further guidance regarding the design and statistical analysis for the COASTAL trial. Following the November meeting, the companies jointly concluded that a clinical trial consistent with the recent FDA guidance, including modification of the ongoing COASTAL trial, would likely not be feasible to complete within a time period that would support further investment or with sufficient certainty of the regulatory requirements for approval to justify continued global development efforts. As a result, we and KKC jointly decided to discontinue global development of zandelisib for indolent forms of non-Hodgkin lymphoma outside of Japan.

The discontinuation of zandelisib development outside of Japan was a business decision based on the most recent regulatory guidance from the FDA and is not related to the zandelisib clinical data generated to date. KKC is continuing certain ongoing Japanese clinical trials, including the Phase 2 MIRAGE trial evaluating Japanese patients with relapsed or refractory indolent B-cell non-Hodgkin lymphomas, and will explore submitting the MIRAGE and TIDAL trials for marketing authorization in Japan. MIRAGE is a Phase 2 trial, similar in design to the global Phase 2, single-arm, TIDAL trial. In November 2022, we and KKC announced positive topline data from the Phase 2 MIRAGE trial.

We and KKC have begun closing all ongoing zandelisib clinical studies outside of Japan, including the Phase 3 COASTAL trial, the Phase 2 TIDAL trial, and the Phase 2 CORAL trial. Depending on the achievement of certain regulatory and commercial milestones in Japan, MEI may be eligible for additional payments from KKC under the current agreement. We are entitled to royalties on any sales of zandelisib in Japan.

In December 2022, we announced a plan to streamline our organization towards the continued clinical development of voruciclib and ME-344. As a result, we initiated a staggered workforce reduction, initially affecting 28 employees in December 2022 (representing approximately 27% of our workforce). In connection with the reduction in force, we incurred termination costs, which include severance, benefits, and related costs of approximately $1.2 million, of which $0.8 million was research and development expense and $0.4 million was general and administrative expense. We have accrued these termination benefits as of December 31, 2022 and paid the associated benefits in January 2023.

Liquidity

We have accumulated losses of $380.5 million since inception and expect to incur operating losses and generate negative cash flows from operations for the foreseeable future. As of December 31, 2022, we had $124.2 million in cash and cash equivalents and short-term investments. We believe that these resources will be sufficient to meet our obligations and fund our liquidity and capital expenditure requirements for at least the next 12 months from the issuance of these financial statements. Our current business operations are focused on continuing the clinical development of our drug candidates. Changes to our research and development plans or other changes affecting our operations and operating expenses may affect actual future use of existing cash resources. We cannot determine with certainty costs associated with ongoing and future clinical trials or the regulatory approval process. The duration, costs and timing associated with the development of our product candidates will depend on a variety of factors, including uncertainties associated with the results of our clinical trials.

To date, we have obtained cash and funded our operations primarily through equity financings and license agreements. In order to continue the development of our drug candidates, at some point in the future we expect to pursue one or more capital transactions, whether through the sale of equity securities, debt financing, license agreements or entry into strategic partnerships. There can be no assurance that we will be able to continue to raise additional capital in the future.

Basis of Presentation

The accompanying unaudited financial statements have been prepared in accordance with accounting principles generally accepted in the U.S. (“U.S. GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, the accompanying financial statements do not include all of the information and notes required by U.S. GAAP for complete financial statements. In the opinion of management, the accompanying financial statements reflect all adjustments (consisting of normal recurring adjustments) that are necessary for a fair statement of the financial position, results of operations and cash flows for the periods presented.

The accompanying unaudited financial statements for the quarterly period ended December 31, 2022 should be read in conjunction with the audited financial statements and notes thereto as of and for the fiscal year ended June 30, 2022, included in our Annual Report on Form 10-K filed with the Securities and Exchange Commission on September 8, 2022 ("2022 Annual Report"). Interim results are not necessarily indicative of results for a full year.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and disclosures made in the accompanying notes to the financial statements. We use estimates that affect the reported amounts (including assets, liabilities, revenues and expenses) and related disclosures. Actual results could materially differ from those estimates.

Fair Value Measurements

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value is as follows:

Revenue Recognition

Revenues from Customers

In accordance with Accounting Standards Codification ("ASC") Topic 606, Revenue from Contracts with Customers ("Topic 606"), we recognize revenue when control of the promised goods or services is transferred to our customers, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. For enforceable contracts with our customers, we

first identify the distinct performance obligations – or accounting units – within the contract. Performance obligations are commitments in a contract to transfer a distinct good or service to the customer.

Payments received under commercial arrangements, such as licensing technology rights, may include non-refundable fees at the inception of the arrangements, milestone payments for specific achievements designated in the agreements, and royalties on the sale of products. At the inception of arrangements that include milestone payments, we use judgment to evaluate whether the milestones are probable of being achieved and we estimate the amount to include in the transaction price using the most likely method. If it is probable that a significant revenue reversal will not occur, the estimated amount is included in the transaction price. Milestone payments that are not within our or the licensee’s control, such as regulatory approvals, are not included in the transaction price until those approvals are received. At the end of each reporting period, we re-evaluate the probability of achievement of development milestones and any related constraint and, as necessary, we adjust our estimate of the overall transaction price.

We may enter into arrangements that consist of multiple performance obligations. Such arrangements may include any combination of our deliverables. To the extent a contract includes multiple promised deliverables, we apply judgment to determine whether promised deliverables are capable of being distinct and are distinct in the context of the contract. If these criteria are not met, the promised deliverables are accounted for as a combined performance obligation. For arrangements with multiple distinct performance obligations, we allocate variable consideration related to our 50-50 cost share for development services directly to the associated performance obligation and then allocate the remaining consideration among the performance obligations based on their relative stand-alone selling price.

Stand-alone selling price is the price at which we would sell a promised good or service separately to the customer. When not directly observable, we typically estimate the stand-alone selling price for each distinct performance obligation. Variable consideration that relates specifically to our efforts to satisfy specific performance obligations is allocated entirely to those performance obligations. Other components of the transaction price are allocated based on the relative stand-alone selling price, over which management has applied significant judgment. We develop assumptions that require judgment to determine the stand-alone selling price for license-related performance obligations, which may include forecasted revenues, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of technical, regulatory and commercial success. We estimate stand-alone selling price for research and development performance obligations by forecasting the expected costs of satisfying a performance obligation plus an appropriate margin.

In the case of a license that is a distinct performance obligation, we recognize revenue allocated to the license from non-refundable, up-front fees at the point in time when the license is transferred to the licensee and the licensee can use and benefit from the license. For licenses that are bundled with other distinct or combined obligations, we use judgment to assess the nature of the performance obligation to determine whether the performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. If the performance obligation is satisfied over time, we evaluate the measure of progress each reporting period and, if necessary, adjust the measure of performance and related revenue recognition.

The selection of the method to measure progress towards completion requires judgment and is based on the nature of the products or services to be provided. Revenue is recorded proportionally as costs are incurred. We generally use the cost-to-cost measure of progress because it best depicts the transfer of control to the customer which occurs as we incur costs. Under the cost-to-cost measure of progress, the extent of progress towards completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation (an “input method” under Topic 606). We use judgment to estimate the total cost expected to complete the research and development performance obligations, which include subcontractors’ costs, labor, materials, other direct costs and an allocation of indirect costs. We evaluate these cost estimates and the progress each reporting period and, as necessary, we adjust the measure of progress and related revenue recognition.

For arrangements that include sales-based or usage-based royalties, we recognize revenue at the later of (i) when the related sales occur or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied or partially satisfied. To date, we have not recognized any sales-based or usage-based royalty revenue from license agreements.

In connection with our License, Development and Commercialization Agreement (the "KKC Commercialization Agreement") with KKC, we perform development services related to our 50-50 cost sharing arrangement for which revenue is recognized over time. Additionally, we perform services for KKC at their request, the costs of which are fully reimbursed to us. We record the reimbursement for such pass through services as revenue at 100% of reimbursed costs, as control of the additional services for KKC is transferred at the time we incur such costs. The costs of these services are recognized in the Condensed Statements of Operations as research and development expense.

Contract Balances

Accounts receivable are included in “Prepaid expenses and other current assets”, and contract liabilities are included in “Deferred revenue" and "Deferred revenue, long-term” on our Condensed Balance Sheets. The following table presents changes in accounts receivable, unbilled receivables and contract liabilities accounted for under Topic 606 for the periods presented (in thousands):

The timing of revenue recognition, invoicing and cash collections results in billed accounts receivable and unbilled receivables and deferred revenue (contract liabilities). We invoice our customers in accordance with agreed-upon contractual terms, typically at periodic intervals or upon achievement of contractual milestones. Invoicing may occur subsequent to revenue recognition, resulting in unbilled receivables. We may receive advance payments from our customers before revenue is recognized, resulting in contract liabilities. The unbilled receivables and deferred revenue reported on the Condensed Balance Sheets relate to the KKC Commercialization Agreement.

As of December 31, 2022 and June 30, 2022, we had $67.4 million and $95.4 million, respectively, of deferred revenue associated with the KKC Commercialization Agreement, of which $64.5 million relates to the U.S. license which is a unit of account under the scope of ASC Topic 808, Collaborative Arrangements ("Topic 808") and is not a performance obligation under Topic 606. The remaining balance of deferred revenue as of December 31, 2022 and June 30, 2022 of $2.9 million and $30.9 million, respectively, relates to the development services performance obligations which are under the scope of Topic 606. The decrease in deferred revenue comes as a result of our beginning the close down of all zandelisib studies outside of Japan. We updated our estimated costs to complete each of the performance obligations, resulting in a higher progress towards completion based on the ratio of costs incurred to date to the total estimated costs. Additionally, we recognized revenue related to non-refundable payments for performance obligations that have not commenced and will no longer be initiated.

Our contract liabilities accounted for under Topic 606 relate to the amount of initial upfront consideration that was allocated to the development services performance obligations. Contract liabilities are recognized over the duration of the performance obligations based on the costs incurred relative to total expected costs.

Revenues from Collaborators

At contract inception, we assess whether the collaboration arrangements are within the scope of Topic 808 to determine whether such arrangements involve joint operating activities performed by parties that are both active participants in the activities and exposed to significant risks and rewards dependent on the commercial success of such activities. This assessment is performed based on the responsibilities of all parties in the arrangement. For collaboration arrangements within the scope of Topic 808 that contain multiple units of account, we first determine which units of account within the arrangement are within the scope of Topic 808 and which elements are within the scope of Topic 606. For units of account within collaboration arrangements that are accounted for pursuant to Topic 808, an appropriate recognition method is determined and applied consistently, by analogy to authoritative accounting literature. For elements of collaboration arrangements that are accounted for pursuant to Topic 606, we recognize revenue as discussed above. Consideration received that does not meet the requirements to satisfy Topic 606 revenue recognition criteria is recorded as deferred revenue in the accompanying Condensed Balance Sheets, classified as either short-term or long-term deferred revenue based on our best estimate of when such amounts will be recognized.

Research and Development Costs

Research and development costs are expensed as incurred and include costs paid to third-party contractors to perform research, conduct clinical trials and develop and manufacture drug materials. Clinical trial costs, including costs associated with third-party contractors, are a significant component of research and development expenses. We expense research and development costs based on work performed. In determining the amount to expense, management relies on estimates of total costs based on contract components completed, the enrollment of subjects, the completion of trials, and other events. Costs incurred related to the purchase or licensing of in-process research and development for early-stage products or products that are not commercially viable and ready for use, or have no alternative future use, are charged to expense in the period incurred.

Leases

We account for our leases under ASC Topic 842, Leases (“Topic 842”). Leases which are identified within the scope of Topic 842 and which have a term greater than one year are recognized on our Condensed Balance Sheets as right-of-use ("ROU") assets and lease liabilities. Operating lease liabilities and their corresponding ROU assets are recorded based on the present value of lease payments over the expected remaining lease term. The lease term includes any renewal options and termination options that we are reasonably certain to exercise. Certain adjustments to the right-of-use asset may be required for items such as initial direct costs paid or incentives received. The present value of lease payments is determined by using the interest rate implicit in the lease, if that rate is readily determinable; otherwise, we use our incremental borrowing rate. The incremental borrowing rate is determined based on the rate of interest that we would pay to borrow on a collateralized basis an amount equal to the lease payments for a similar term and in a similar economic environment. The interest rate implicit in lease contracts to calculate the present value is typically not readily determinable. As such, significant management judgment is required to estimate the incremental borrowing rate.

Rent expense for operating leases is recognized on a straight-line basis over the lease term based on the total lease payments. We have elected the practical expedient to not separate lease and non-lease components for our real estate leases. Our non-lease components are primarily related to property maintenance, which varies based on future outcomes, and thus is recognized in rent expense when incurred.

Share-Based Compensation

Share-based compensation expense stock options and restricted stock units ("RSUs") granted to employees and directors is recognized in the Condensed Statements of Operations based on estimated amounts. The cost of stock options is measured at the grant

date, based on the estimated fair value of the stock option using the Black-Scholes valuation model, which incorporates various assumptions, including expected volatility, risk-free interest rate, the expected term of the award and the dividend yield on the underlying stock. Expected volatility is calculated based on the historical volatility of our stock over the expected option life and other appropriate factors. The expected option term is computed using the "simplified" method as permitted under the provisions of ASC Topic 718, Compensation - Stock Compensation. We use the simplified method to calculate the expected term of stock options and similar instruments, as we do not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term. Risk-free interest rates are calculated based on continuously compounded risk-free rates for the appropriate term. The dividend yield is assumed to be zero as we have never paid or declared any cash dividends and do not intend to do so in the foreseeable future. For RSUs, we estimate the grant date fair value using our closing stock price on the date of grant. The estimated fair value of stock options and RSUs is amortized on a straight-line basis over the requisite service period, adjusted for actual forfeitures at the time they occur. The requisite service period is generally the time over which our share-based awards vest.

Income Taxes

Our income tax expense consists of current and deferred income tax expense or benefit. Current income tax expense or benefit is the amount of income taxes expected to be payable or refundable for the current year. A deferred income tax asset or liability is recognized for the future tax consequences attributable to tax credits and loss carryforwards and to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized. As of December 31, 2022, we have established a valuation allowance to fully reserve our net deferred tax assets. Tax rate changes are reflected in income during the period such changes are enacted. Changes in our ownership may limit the amount of net operating loss carryforwards that can be utilized in the future to offset taxable income.

There have been no material changes in our unrecognized tax benefits since June 30, 2022, and, as such, the disclosures included in our 2022 Annual Report continue to be relevant for the six months ended December 31, 2022.

Recent Accounting Pronouncement

In June 2016, the Financial Accounting Standards Board issued Accounting Standards Update 2016-13, Financial Instruments–Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"), as amended. The amendments in ASU 2016-13 require, among other things, financial assets measured at amortized cost basis to be presented at the net amount expected to be collected as compared to previous U.S. GAAP which delayed recognition until it was probable a loss had been incurred. The amendments in ASU 2016-13 are effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years, with early adoption permitted. We are currently evaluating the impact that adoption of ASU 2016-13 will have on our financial statements and related disclosures.