On November 16, 2021, we received $10.0 million in net proceeds from issuance of an unsecured promissory note, or 2021 Note, with face amount of $10.2 million. The note bears interest at a rate of 9.5% per annum, matures January 1, 2023, and includes an original issue discount of $0.2 million. We may prepay all or a portion of the note at any time by paying 105% of the outstanding balance elected for pre-payment.
In November 2021, we issued in an underwritten public offering an aggregate of 46,000,000 shares of common stock at a purchase price per share of $1.25 for $54.0 million in net proceeds after payment of underwriter discounts and commissions and other underwriter offering costs. GMS Ventures purchased an aggregate of 16,000,000 shares of common stock in the public offering at the public offering price per share. In connection with the underwritten public offering, we issued the underwriter warrants to purchase up to an aggregate of 2,100,000 shares of common stock at an exercise price of $1.5625 per share, which warrants have a 5-year term.
During the period from October 2021 through April 2022, we sold 3,440,416 shares of common stock under, and generated $6.7 million in net proceeds from, the ATM Offering after payment of fees to the sales agent of $0.2 million.
We evaluated whether there are conditions or events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern. As of March 31, 2022, we had an accumulated deficit of $377.1 million. In addition, $22.6 million of unsecured promissory notes, which bear interest compounding daily and mature January 1, 2023 and a $0.2 million loan granted pursuant to the PPP of the CARES Act are outstanding as of March 31, 2022. The PPP loan was fully repaid on May 2, 2022. As a result, there is substantial doubt about our ability to continue as a going concern. Our current cash resources of $58.4 million as of March 31, 2022 are expected to fund our operations through the anticipated approval of the ONS-5010 BLA expected in the first calendar quarter of 2023.
Our future operations are highly dependent on a combination of factors, including (i) the timely and successful completion of additional financing discussed above, (ii) our ability to successfully begin marketing of our product candidates or complete revenue-generating partnerships with other companies, (iii) the success of our research and development, (iv) the development of competitive therapies by other biotechnology and pharmaceutical companies, and, ultimately, (v) regulatory approval and market acceptance of our proposed future products.
Funding Requirements
We anticipate we will incur net losses and negative cash flow from operations for the foreseeable future. We may not be able to complete the development and initiate commercialization of ONS-5010 if, among other things, if the FDA does not approve our BLA when we expect, or at all, or if we are not able to enter into strategic partnerships for ONS-5010 providing for sufficient funding of our expected commercial and development costs and we are unable to obtain such funding elsewhere.
Our primary uses of capital are, and we expect will continue to be, compensation and related expenses, manufacturing and facility costs, external research and development services, laboratory and related supplies, legal and other regulatory expenses, and administrative and overhead costs. Our future funding requirements will be heavily determined by the resources needed to support development of our lead product candidate and any other product candidates we may choose to pursue.
We believe our existing cash of $58.4 million as of March 31, 2022, can fund our operations into the first calendar quarter of 2023. We have based this estimate on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we expect. We may need to raise substantial additional capital to complete our planned ONS-5010 development and commercialization program. We plan to finance our future operations with a combination of proceeds from our ATM facility, renegotiation of the maturity date for existing unsecured notes, proceeds from potential licensing and/or marketing arrangements or collaborations with pharmaceutical or other companies, the issuance of equity securities, the issuance of additional debt, and revenues from potential future product sales, if any. If we raise additional capital through the sale of equity or convertible debt securities, your ownership will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect your rights as a holder of our common stock. There are no assurances that we will be successful in obtaining an adequate level of financing for the development and commercialization of ONS-5010 or any other current or future product candidates. Alternatively, we will be required to, among other things, modify our clinical trial plans for ONS-5010 in additional indications, make reductions in our