Interest Expense. We did not incur any interest expense for the three months ended September 30, 2022 due to the repayment of the Loan Agreement on June 30, 2022, whereas we incurred $0.4 million of interest expense for the three months ended September 30, 2021. Interest expense for the three months ended September 30, 2021 was solely attributable to the Loan Agreement and consisted of (i) interest expense of $0.3 million based on the weighted average contractual rate of 9.0%, and (ii) accretion of discount of $0.1 million.
Income Taxes. For the three months ended September 30, 2022 and 2021, we did not recognize any income tax benefit due to our net losses, and our determination that a valuation allowance was required for all of our deferred tax assets.
Liquidity and Capital Resources
Short-term Liquidity Requirements
As of September 30, 2022, we had cash and cash equivalents of $154.3 million and working capital was approximately $153.2 million. We have incurred cumulative net losses of $219.0 million since our inception and as a clinical stage company we have not generated any meaningful revenue to date.
Our primary source of liquidity has historically been from the completion of private placements and public offerings of our equity securities, as well as proceeds from the issuance of debt securities. For the three months ended September 30, 2022, as discussed above under the caption Recent Developments, we issued common stock in the 2022 Private Placement that resulted in net proceeds of $11.6 million. For the fiscal year ended June 30, 2022, we received net proceeds from the issuance of equity securities of $165.2 million. The completion of these equity financings is the primary factor that resulted in our cash and cash equivalents balance of $154.3 million as of September 30, 2022. For further information about the key terms and results of our debt and equity financing activities, please refer to the discussion below under the captions 2022 Registered Direct Offering, 2021 Underwritten Public Offering and 2021 Registered Direct Offering.
Our most significant contractual obligations consist of milestone payments pursuant to licensing agreements with XOMA Corporation (“XOMA”) and ActiveSite Pharmaceuticals, Inc. (“ActiveSite”) discussed below. Based on our expectations for the dates when certain clinical and regulatory milestones will be achieved, we anticipate that $5.0 million will be payable to XOMA and $3.0 million will be payable to ActiveSite within the next twelve months.
Based on our cash and cash equivalents balance of $154.3 million as of September 30, 2022, we believe we have adequate capital resources to meet all of our contractual obligations and conduct all planned activities to advance our clinical trials during through the fiscal quarter ending September 30, 2023.
Long-term Liquidity Requirements
Our most significant long-term contractual obligations consist of clinical and regulatory milestone payments up to $35.0 million payable to XOMA and up to $45.5 million in milestones payable to ActiveSite, for a total of $80.5 million. As discussed above, we expect that $5.0 million will be payable to XOMA and $3.0 million will be payable to ActiveSite during the next twelve months. Accordingly, the remainder of $72.5 million is considered a long-term liquidity requirement. Our current expectations are that we will incur additional milestone payments of $5.0 million payable to XOMA for the fiscal year ending June 30, 2024. Due to uncertainties in the timing associated with clinical trial activities and regulatory approvals, there is even greater uncertainty in forecasting the milestone payments to XOMA and ActiveSite during the fiscal year ending June 30, 2024 and thereafter.
Our long-term contractual obligations also include (i) operating lease payments up to approximately $0.7 million per year through calendar year 2027, and (ii) an exit fee of $0.6 million if we enter into certain transactions (defined as “Exit Events”) prior to April 13, 2031. Exit Events include, but are not limited to, sales of substantially all assets, certain mergers, change of control transactions, and issuances of common stock that result in new investors owning more than 35% of the Company’s shares. As discussed above under the caption Recent Developments, on June 30, 2022 we terminated the Loan Agreement with SLR. However, we remain contingently obligated to pay the $0.6 million exit fee.
The following discussion provides additional information about the ongoing requirements pursuant to our license agreements with XOMA and ActiveSite, along with additional information about our recent financing activities that impacted our liquidity and capital resources through September 30, 2022.