4. Licensing and Other Arrangements

Novartis International – Anti-TGFβ Antibody (NIS793)

On September 30, 2015, the Company and Novartis International Pharmaceutical Ltd. (“Novartis International”) entered into a license agreement (the “Anti-TGFβ Antibody License Agreement”) under which the Company granted Novartis International an exclusive, world-wide, royalty-bearing license to the Company’s anti-transforming growth factor beta (“TGFβ”) antibody program (now “NIS793”). Under the terms of the Anti-TGFβ Antibody License Agreement, Novartis International has worldwide rights to NIS793 and is responsible for the development and commercialization of antibodies and products containing antibodies arising from NIS793. Unless terminated earlier, the Anti-TGFβ Antibody

License Agreement will remain in effect, on a country-by-country and product-by-product basis, until Novartis International’s royalty obligations end. The Anti-TGFβ Antibody License Agreement contains customary termination rights relating to material breach by either party. Novartis International also has a unilateral right to terminate the Anti-TGFβ Antibody License Agreement on an antibody-by-antibody and country-by-country basis or in its entirety on one hundred eighty days’ notice.

The Company concluded that there were multiple promised goods and services under the Anti-TGFβ Antibody License Agreement, including the transfer of license, regulatory services and transfer of materials, process and know-how, which were determined to represent one combined performance obligation. The Company recognized the entire upfront payment of $37.0 million as revenue in the consolidated statement of comprehensive loss in 2015 as it had completed its performance obligations as of December 31, 2015.

The Company is eligible to receive up to a total of $480.0 million in development, regulatory and commercial milestones under the Anti-TGFβ Antibody License Agreement. During the year ended December 31, 2017, Novartis International achieved a clinical development milestone pursuant to the Anti-TGFβ Antibody License Agreement, and as a result, the Company earned a $10.0 million milestone payment which was recognized as license fees in the consolidated statement of operations and comprehensive loss.

The Company concluded that the development and regulatory milestone payments are solely dependent on Novartis International’s performance and achievement of the specified events. The Company determined that it is not probable that a significant cumulative revenue reversal will not occur in future periods for these future payments. Therefore, the remaining development and regulatory milestones are fully constrained and excluded from the transaction price until the respective milestone is achieved. Any consideration related to commercial milestones (including royalties) will be recognized when the related sales occur as they were determined to relate predominantly to the licenses granted to Novartis International and therefore, have also been excluded from the transaction price. At the end of each reporting period, the Company will update its assessment of whether an estimate of variable consideration is constrained and update the estimated transaction price accordingly.

The Company is also eligible to receive royalties on sales of licensed products, which are tiered based on sales levels and range from a mid single-digit percentage rate to up to a low double-digit percentage rate. Novartis International’s obligation to pay royalties with respect to a particular product and country will continue for the longer of the date of expiration of the last valid patent claim covering the product in that country, or ten years from the date of the first commercial sale of the product in that country.

On October 21, 2020, the first patient was dosed in Novartis International's NIS793 Phase 2 clinical trial and the Company earned a $25.0 million milestone payment. As specified under the terms the Anti-TGFβ Antibody License Agreement, the Company received $17.7 million in cash and the remaining balance of $7.3 million was recognized as a reduction to the Company's debt obligation to Novartis. The Company is eligible to receive up to a total of $445.0 million in the remaining development, regulatory and commercial milestones under the Anti-TGFβ Antibody License Agreement.

As of March 31, 2021 and December 31, 2020, there were no contract assets or contract liabilities related to this agreement. None of the costs to obtain or fulfill the contract were capitalized. No revenue was recognized for the three months ended March 31, 2021 and 2020.

Novartis – Gevokizumab (VPM087) and IL-1 Beta

On August 24, 2017, the Company and Novartis Pharma AG (“Novartis”) entered into a license agreement (the “Gevokizumab License Agreement”) under which the Company granted to Novartis an exclusive, worldwide, royalty-bearing license to gevokizumab (“VPM087”), a novel anti-Interleukin-1 (“IL-1”) beta allosteric monoclonal antibody and related know-how and patents (altogether, the “XOMA IP”). Under the terms of the Gevokizumab License Agreement, Novartis is solely responsible for the development and commercialization of VPM087 and products containing VPM087.

On August 24, 2017, pursuant to a separate agreement (the “IL-1 Target License Agreement”), the Company granted to Novartis non-exclusive licenses to its intellectual property covering the use of IL-1 beta targeting antibodies in

the treatment and prevention of cardiovascular disease and other diseases and conditions, and an option to obtain an exclusive license (the “Exclusivity Option”) to such intellectual property for the treatment and prevention of cardiovascular disease.

Under the Gevokizumab License Agreement, the Company received total consideration of $30.0 million for the license and rights granted to Novartis. Of the total consideration, $15.7 million was paid in cash and $14.3 million (equal to €12.0 million) was paid by Novartis Institutes for BioMedical Research, Inc. (“NIBR”), on behalf of the Company, to settle the Company’s outstanding debt with Les Laboratories Servier (“Servier”) (the “Servier Loan”). In addition, NIBR extended the maturity date on the Company’s debt to Novartis. The Company also received $5.0 million cash related to the sale of 539,131 shares of the Company’s common stock, at a purchase price of $9.2742 per share. The fair market value of the common stock issued to Novartis was $4.8 million, based on the closing stock price of $8.93 per share on August 24, 2017, resulting in a $0.2 million premium paid to the Company.

Based on the achievement of pre-specified criteria, the Company is eligible to receive up to $438.0 million in development, regulatory and commercial milestones under the Gevokizumab License Agreement. The Company is also eligible to receive royalties on sales of licensed products, which are tiered based on sales levels and range from the high single-digits to mid-teens. Under the IL-1 Target License Agreement, the Company received an upfront cash payment of $10.0 million and is eligible to receive low single-digit royalties on canakinumab sales in cardiovascular indications covered by the Company’s patents. Should Novartis exercise the Exclusivity Option, the royalties on canakinumab sales will increase to the mid single-digits.

Unless terminated earlier, the Gevokizumab License Agreement and IL-1 Target License Agreement will remain in effect, on a country-by-country and product-by-product basis, until Novartis’ royalty obligations end. The two agreements contain customary termination rights relating to material breach by either party. Novartis also has a unilateral right to terminate the Gevokizumab License Agreement on a product-by-product and country-by-country basis or in its entirety on six months’ prior written notice to the Company. Under the IL-1 Target License Agreement, Novartis has a unilateral right to terminate the agreement on a product-by-product and country-by-country basis or in its entirety upon a prior written notice.

The Gevokizumab License Agreement and IL-1 Target License Agreement were accounted for as one arrangement because they were entered into at the same time in contemplation of each other. The Company concluded that there are multiple promised goods and services under the combined arrangement, including the transfer of license to IL-1 beta targeting antibodies, and the transfer of license, know-how, process, materials and inventory related to the VPM087 antibody, which were determined to represent two distinct performance obligations. The Company determined that the Exclusivity Option is not an option with material right because the upfront payments to the Company were not negotiated to provide an incremental discount for the future additional royalties upon exercise of the Exclusivity Option. Therefore, the Company concluded that the Exclusivity Option is not a performance obligation. The additional royalties will be recognized as revenue when, and if, Novartis exercises its option because the Company has no further performance obligations at that point.

At the inception of the arrangement, the Company determined that the transaction price under the arrangement was $40.2 million, which consisted of the $25.7 million upfront cash payments, the $14.3 million Servier Loan payoff and the $0.2 million premium on the sale of the common stock. The transaction price was allocated to the two performance obligations based on their standalone selling prices. The Company determined that the nature of the two performance obligations is the right to use the licenses as they exist at the point of transfer, which occurred when the transfer of materials, process and know-how, and filings to regulatory authority were completed. During the year ended December 31, 2017, the Company recognized the entire transaction price of $40.2 million as revenue upon completion of the delivery of the licenses and related materials, process and know-how and filings to regulatory authority.

The Company concluded that the development and regulatory milestone payments are solely dependent on Novartis’ performance and achievement of specified events. The Company determined that it is not probable that a significant cumulative revenue reversal will not occur in future periods for these future payments. Therefore, the development and regulatory milestones are fully constrained and excluded from the transaction price until the respective milestone is achieved. Any consideration related to commercial milestones (including royalties) will be recognized when

the related sales occur as they were determined to relate predominantly to the licenses granted to Novartis and therefore, have also been excluded from the transaction price. At the end of each reporting period, the Company will update its assessment of whether an estimate of variable consideration is constrained and update the estimated transaction price accordingly.

As of March 31, 2021 and December 31, 2020, there were no contract assets or contract liabilities related to this arrangement. None of the costs to obtain or fulfill the contract were capitalized. No revenue was recognized for the three months ended March 31, 2021 and 2020.

Takeda

On November 1, 2006, the Company entered into a collaboration agreement with Takeda Pharmaceutical Company Limited (“Takeda”) (the “Takeda Collaboration Agreement”) under which the Company agreed to discover and optimize therapeutic antibodies against multiple targets selected by Takeda.

Under the terms of the Takeda Collaboration Agreement, the Company may receive additional milestone payments aggregating up to $19.0 million relating to TAK-079 (mezagitamab) and low single-digit royalties on future sales of all products subject to this license. The Company’s right to milestone payments expires on the later of the receipt of payment from Takeda of the last amount to be paid under the agreement or the cessation by Takeda of all research and development activities with respect to all program antibodies, collaboration targets or collaboration products. The Company’s right to royalties expires on the later of 13.5 years from the first commercial sale of each royalty-bearing discovery product or the expiration of the last-to-expire licensed patent (or 12 years from first commercial sale if there is significant generic competition post patent-expiration).

In February 2009, the Company expanded the existing collaboration to provide Takeda with access to multiple antibody technologies, including a suite of research and development technologies and integrated information and data management systems. The Company may receive milestones of up to $3.3 million per discovery product candidate and low single-digit royalties on future sales of all antibody products subject to this license. The Company’s right to milestone payments expires on the later of the receipt of payment from Takeda of the last amount to be paid under the agreement or the cessation by Takeda of all research and development activities with respect to all program antibodies, collaboration targets or collaboration products. The Company’s right to royalties expires on the later of 10 years from the first commercial sale of such royalty-bearing discovery product or the expiration of the last-to-expire licensed patent.

On November 16, 2020, the first patient was dosed in Takeda’s Phase 2 study of mezagitamab, and the Company earned a $2.0 million milestone payment from Takeda.

As of March 31, 2021 and December 31, 2020, there were no contract assets or contract liabilities related to this arrangement. None of the costs to obtain or fulfill the contract were capitalized. No revenue was recognized for the three months ended March 31, 2021 and 2020.

Rezolute

On December 6, 2017, the Company entered into a license agreement with Rezolute pursuant to which the Company granted an exclusive global license to Rezolute to develop and commercialize X358 (now “RZ358”) products for all indications. The Company and Rezolute also entered into a common stock purchase agreement pursuant to which Rezolute agreed to issue to the Company, as consideration for receiving the license for RZ358, a certain number of its common stock related to its future financing activities.

Under the terms of the license agreement, Rezolute is responsible for all development, regulatory, manufacturing and commercialization activities associated with RZ358 and is required to make certain development, regulatory and commercial milestone payments to the Company of up to $232.0 million in the aggregate based on the achievement of pre-specified criteria. Under the license agreement, the Company is also eligible to receive royalties ranging from the high single-digits to the mid-teens based upon annual net sales of any commercial product incorporating RZ358. Rezolute is obligated to take customary steps to advance RZ358, including using diligent efforts to commence the next clinical study

for RZ358 by a certain deadline and to meet certain spending requirements on an annual basis for the program until a marketing approval application for RZ358 is accepted by the FDA. Rezolute’s obligation to pay royalties with respect to a particular RZ358 product and country will continue for the longer of the date of expiration of the last valid patent claim covering the product in that country, or twelve years from the date of the first commercial sale of the product in that country. Rezolute’s future royalty obligations in the United States will be reduced by 20% if the manufacture, use or sale of a licensed product is not covered by a valid XOMA patent claim, until such a claim is issued.

Under the terms of the license agreement, the Company is eligible to receive a low single-digit royalty on sales of Rezolute’s other non-RZ358 products from its current programs. Rezolute’s obligation to pay royalties with respect to a particular Rezolute product and country will continue for the longer of twelve years from the date of the first commercial sale of the product in that country or for so long as Rezolute or its licensee is selling such product in such country (the “Royalty Term”), provided that any such licensee royalty will terminate upon the termination of the licensee’s obligation to make payments to Rezolute based on sales of such product in such country.

Rezolute had an option through June 1, 2019 to obtain an exclusive license for their choice of one of the Company’s preclinical monoclonal antibody fragments, including X129 (the “Additional Product Option”), in exchange for a $1.0 million upfront option fee and additional clinical, regulatory and commercial milestone payments to the Company of up to $237.0 million in the aggregate based on the achievement of pre-specified criteria as well as royalties ranging from the high single-digits to the mid-teens based on annual net sales. On June 1, 2019, Rezolute’s right to the Additional Product Option expired unexercised.

The license agreement contains customary termination rights relating to material breach by either party. Rezolute also has a unilateral right to terminate the license agreement in its entirety on ninety days’ notice at any time. The Company has the right to terminate the license agreement if Rezolute challenges the licensed patents.

Under the license agreement and common stock purchase agreement, no consideration was exchanged upon execution of the arrangement. In consideration for receiving the license for RZ358, Rezolute agreed to issue shares of its common stock and pay cash to the Company upon the occurrence of Rezolute’s financing activities and the amounts to be paid to be based on the timing of those activities.

Rezolute License Agreement - First Amendment

In March 2018, the Company and Rezolute amended the license agreement and common stock purchase agreement. Pursuant to the as-amended terms of the license agreement and common stock purchase agreement, the Company was eligible to receive $6.0 million in cash, $8.5 million of Rezolute’s common stock, and 7,000,000 shares (140,000 post-split shares) of Rezolute’s common stock, contingent on the completion of Rezolute’s financing activities. Further, in the event that Rezolute did not complete a financing that raised at least $20.0 million in aggregate gross proceeds (“Qualified Financing”) by March 31, 2019 (the “2019 Closing”), the Company would have received an additional number of shares of Rezolute’s common stock equal to $8.5 million divided by the weighted average of the closing bid and ask prices or the average closing prices of Rezolute’s common stock on the ten-day trading period prior to March 31, 2019. Finally, in the event that Rezolute was unable to complete a Qualified Financing by March 31, 2020, the Company would have been eligible to receive $15.0 million in cash in order for Rezolute to maintain the license. Under the common stock purchase agreement, Rezolute granted the Company the right and option to sell the greater of (i) 5,000,000 shares (100,000 post-split shares) of common stock or (ii) one third of the aggregate shares held by the Company upon failure by Rezolute to list its shares of its common stock on the Nasdaq Stock Market or a similar national exchange on or prior to December 31, 2018.

During the three months ended March 31, 2018, the Company completed the delivery of the license and related materials, product data/filing, process and know-how to Rezolute. However, the Company determined that it was not probable that the Company would collect substantially all of the consideration to which it was entitled in exchange for the goods and services transferred to Rezolute. Therefore, the Company determined no contract existed as of March 31, 2018 and no revenue was recognized during the three months ended March 31, 2018 under the arrangement.

Rezolute completed the Interim Financing Closing and the Initial Closing financing activities, as defined in the common stock purchase agreement, during the first and second quarter of 2018, respectively. As a result, XOMA received 8,093,010 shares (161,860 post-split shares) of Rezolute’s common stock and cash of $0.5 million in April 2018. Under the license agreement, XOMA was also entitled to receive $0.3 million of reimbursable technology transfer expenses from Rezolute. The Company concluded that the payment associated with the Initial Closing represented substantially all consideration for the delivered license and technology to Rezolute. Therefore, the Company determined that a contract existed between Rezolute and XOMA under ASC 606 on April 3, 2018.

The license agreement and common stock purchase agreement were accounted for as one arrangement because they were entered into at the same time in contemplation of each other. The Company concluded that there were multiple promised goods and services under the combined arrangement, including the license to RZ358, the transfer of RZ358 materials and product data/filing, and the transfer of process and know-how related to RZ358, which were determined to represent one combined performance obligation. The Company determined that the Additional Product Option was not an option with material right because there was no upfront consideration to the Company that would result to an incremental discount for the future opt in payments. Therefore, the Company concluded that the Additional Product Option was not a performance obligation. On June 1, 2019, Rezolute’s right to the Additional Product Option expired unexercised.

On April 3, 2018, the Company determined that the transaction price under the arrangement was $1.8 million, which consisted of the 8,093,010 shares (161,860 post-split shares) of Rezolute’s common stock valued at $1.0 million, $0.5 million in cash, and reimbursable technology transfer expenses of $0.3 million. During the year ended December 31, 2018, the Company recognized the entire transaction price of $1.8 million as revenue upon completion of the delivery of the licenses and related materials, product data/filing, process and know-how. The change in fair value of Rezolute’s common stock after the contract inception date was due to the form of the consideration and therefore, not included in the transaction price pursuant to the accounting guidance. The Company accounts for the change in the fair value of its investment in Rezolute’s common stock in the other income (expense), net line item of the condensed consolidated statement of operations and comprehensive loss.

The Company concluded that the development and regulatory milestone payments are solely dependent on Rezolute’s performance and achievement of the specified events. The Company determined that it is not probable that a significant cumulative revenue reversal will not occur in future periods for these future payments. Therefore, the development and regulatory milestones are fully constrained and excluded from the transaction price as of the inception of the arrangement. Any consideration related to commercial milestones (including royalties) will be recognized when the related sales occur as they were determined to relate predominantly to the licenses granted to Rezolute and therefore, have also been excluded from the transaction price. At the end of each reporting period, the Company will update its assessment of whether the estimate of variable consideration is constrained and update the estimated transaction price accordingly.

Rezolute License Agreement - Second Amendment

On January 7, 2019, the Company and Rezolute further amended the license agreement and common stock purchase agreement. The parties agreed to replace the issuance of common stock valued at $8.5 million to XOMA upon closing of a Qualified Financing with a requirement that Rezolute make five future cash payments to XOMA totaling $8.5 million through September 2020 (the “Future Cash Payments”). The amendment also provided for early payment of the Future Cash Payments (only until the $8.5 million was reached) by making cash payments to XOMA equal to 15% of the net proceeds of each future financing following the closing of the Qualified Financing, with such payments to be credited against any remaining unpaid Future Cash Payments in reverse order of their future payment date. In addition, the license agreement amendment revised the amount Rezolute is required to expend on development of RZ358 and related licensed products, revised provisions with respect to Rezolute’s diligence efforts in conducting clinical studies and eliminated XOMA’s right to appoint a member to Rezolute’s board of directors.

The common stock purchase agreement was amended to remove certain provisions related to the issuance of equity to XOMA in accordance with the new provisions regarding the Future Cash Payments in the license agreement. Lastly, the common stock purchase agreement was amended to provide the Company the right and option to sell up to 5,000,000 shares (100,000 post-split shares) of Rezolute’s common stock currently held by XOMA back to Rezolute upon failure by Rezolute to list its shares of its common stock on the Nasdaq Stock Market or a similar national exchange on or

prior to December 31, 2019. As of December 31, 2019, Rezolute failed to list its shares of common stock on the Nasdaq Stock Market or a similar exchange. Up to 2,500,000 shares (50,000 post-split shares) may be sold back to Rezolute during calendar year 2020. During the quarter ended December 31, 2020 Rezolute began trading on the Nasdaq Stock Market and the Company has not sold any of its shares.

On January 30, 2019, Rezolute closed a preferred stock financing for gross proceeds of $25.0 million, which triggered the Qualified Financing event defined under the amended common stock purchase agreement resulting in cash consideration due to XOMA of $5.5 million. In addition, the Company received from Rezolute a reimbursable technology transfer expense of $0.3 million. The cash consideration and technology reimbursement were received in February 2019.

As of March 31, 2019, Rezolute completed all financing activities, as defined in the license agreement and common stock purchase agreement, and the Company was eligible to receive $8.5 million in Future Cash Payments through September 2020 (in addition to any clinical, regulatory and annual net sales milestone payments and royalties). The Company concluded that the Future Cash Payments are dependent on Rezolute’s ability to raise additional capital through future financing activities. During 2019, the Company recognized all $8.5 million Future Cash Payments as revenue and received $5.9 million Future Cash Payment from Rezolute.

Rezolute License Agreement - Third Amendment

On March 31, 2020, the Company and Rezolute further amended the license agreement to extend the payment schedule for the remaining $2.6 million in Future Cash Payments. The amendment to the payment terms was in response to Rezolute’s need to preserve cash as a result of the COVID-19 pandemic and was agreed to by the Company. The extended payment schedule did not impact the total amount due, but instead, spread the $2.6 million into seven quarterly payments to be paid through September 30, 2021. The amended license agreement requires that in the event Rezolute completes a Qualified Financing at any time between March 31, 2020 and the date of the final payment, Rezolute shall pay all amounts outstanding within fifteen days following the closing of the Qualified Financing.

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In the first quarter of 2020, the Company received the scheduled $0.4 million Future Cash Payment from Rezolute. The Company evaluated Rezolute’s cash position as of March 31, 2020, including the estimated impact of the COVID-19 pandemic, and determined payments scheduled beyond September 30, 2020 were unlikely to be collected unless Rezolute was able to obtain additional funding, which had not occurred as of March 31, 2020. Therefore, for the three months ended March 31, 2020, the Company recorded $1.4 million in bad debt expense related to the Future Cash Payments. The Company received the scheduled $0.4 million and $0.4 million Future Cash Payments from Rezolute in the second and third quarters of 2020, respectively. The Company reassessed the collectability of the outstanding receivables and determined that the bad debt allowance of $1.4 million remained appropriate as of September 30, 2020, as the Company assessed that the financing was not probable as of the balance sheet date and as such the Company continued to have an incurred loss with respect to the collection of the remaining receivable.

On October 9, 2020, Rezolute completed a private placement of its equity securities with gross proceeds of $41.0 million, which was considered a Qualified Financing event under the Third Amendment. The Qualified Financing resulted in acceleration of the remaining receivables of $1.4 million due from Rezolute, and the Company received the entire amount in October 2020. The Company recognized $1.4 million as a reversal of bad debt expense in the fourth quarter of 2020.

During the quarter ended December 31, 2020, Rezolute completed a 1:50 reverse stock split of its common shares and started trading on the Nasdaq Stock Market. As a result, the Company’s number of shares of Rezolute common stock was reduced from 8,093,010 shares (pre-split shares) to 161,860 shares (post-split shares).

As of March 31, 2021 and December 31, 2020, there were no contract assets or contract liabilities related to this arrangement. None of the costs to obtain or fulfill the contract were capitalized. No revenue was recognized for the three months ended March 31, 2021 and 2020.

The Company reassessed the development and regulatory milestones and concluded that such variable consideration is fully constrained and excluded from the transaction price as of March 31, 2021 and December 31, 2020.

Janssen Biotech

The Company and Janssen Biotech, Inc. (“Janssen”) were parties to a license agreement which was terminated in 2017. In August 2019, the Company and Janssen entered into a new agreement pursuant to which the Company granted a non-exclusive license to Janssen to develop and commercialize certain drug candidates under the XOMA patents and know-how. Under the new agreement, Janssen made a one-time payment of $2.5 million to XOMA. Additionally, for each drug candidate, the Company is entitled to receive milestone payments of up to $3.0 million upon Janssen’s achievement of certain clinical development and regulatory approval events. Additional milestones may be due for drug candidates which are the subject of multiple clinical trials. Upon commercialization, the Company is eligible to receive 0.75% royalty on net sales of each product. Janssen’s obligation to pay royalties with respect to a particular product and country will continue until the eighth-year and sixth-month anniversary of the first commercial sale of the product in such country. The new agreement will remain in effect unless terminated by mutual written agreement of the parties.

The Company concluded that the new agreement should be accounted for separately from any prior arrangements with Janssen and that the license grant is the only performance obligation under the new agreement. The Company recognized the entire one-time payment of $2.5 million as revenue in the consolidated statement of operations and comprehensive loss for the year ended December 31, 2019 as it had completed its performance obligation.

The Company concluded that the development and regulatory milestone payments are solely dependent on Janssen’s performance and achievement of specified events and thus it is not probable that a significant cumulative revenue reversal will not occur in future periods for these future payments. Therefore, the development and regulatory milestones are fully constrained and excluded from the transaction price until the respective milestone is achieved. Any consideration related to royalties will be recognized when the related sales occur as they were determined to relate predominantly to the license granted to Janssen and therefore, have also been excluded from the transaction price. At the end of each reporting period, the Company will update its assessment of whether an estimate of variable consideration is constrained and update the estimated transaction price accordingly.

As of March 31, 2021 and December 31, 2020, there were no contract assets or contract liabilities related to this arrangement. None of the costs to obtain or fulfill the contract were capitalized. No revenue was recognized for the three months ended March 31, 2021 and 2020.

NIAID

Prior to the sale of the Company’s biodefense business in 2017, the Company performed services under a $64.8 million multiple-year contract funded with federal funds from NIAID (Contract No. HHSN272200800028C), for development of anti-botulinum antibody product candidates. The contract work was being performed on a cost-plus fixed fee basis over a three-year period. The Company recognized revenue under the arrangement as the services were performed on a proportional performance basis. Consistent with the Company’s other contracts with the U.S. government, invoices were provisional until finalized. The Company operated under provisional rates from 2010 through 2014, subject to adjustment based on actual rates upon agreement with the government. In 2014, upon completion of NIAID’s review of hours and external expenses, XOMA agreed to exclude certain hours and external expenses resulting in a $0.4 million receivable and $0.8 million deferred revenue balances. As of December 31, 2017, the Company wrote off the $0.4 million receivable from NIAID as the likelihood of collection was remote. In October of 2019, NIH, which includes NIAID, notified the Company that it engaged KPMG to perform an audit of the Company’s incurred cost submissions for 2013, 2014 and 2015. The KPMG testing procedures were completed in December 2020. As a result, the Company recognized $1.4 million as estimated refund liabilities owed to NIH on the consolidated balance sheet as of December 31, 2020. The additional $0.6 million liability was recognized as a reduction of revenue from contracts with customers in the consolidated statement of operations and comprehensive income (loss) for the year ended December 31, 2020. The audit remains subject to further review by NIH as part of the contract close-out process, which includes finalization of rates for years 2010 through 2015, and the Company may incur a further liability as a result. The Company had $1.4 million as contingent liabilities on the condensed consolidated balance sheets as of March 31, 2021 and December 31, 2020, related to these matters.

Sale of Future Revenue Streams

On December 21, 2016, the Company entered into two royalty interest sale agreements (together, the “Royalty Sale Agreements”) with HCRP. Under the first Royalty Sale Agreement, the Company sold its right to receive milestone payments and royalties on future sales of products subject to a License Agreement, dated August 18, 2005, between XOMA and Wyeth Pharmaceuticals (subsequently acquired by Pfizer, Inc. (“Pfizer”)) for an upfront cash payment of $6.5 million, plus potential additional payments totaling $4.0 million in the event three specified net sales milestones were met in 2017, 2018 and 2019. Based on actual sales, 2017, 2018, and 2019 sales milestones were not achieved. Under the second Royalty Sale Agreement entered into in December 2016, the Company sold its right to receive certain royalties under an Amended and Restated License Agreement dated October 27, 2006 between XOMA and Dyax Corp. for a cash payment of $11.5 million.

The Company classified the proceeds received from HCRP as unearned revenue, to be recognized as revenue under units-of-revenue method over the life of the license agreements because of the Company’s limited continuing involvement in the Acquisition Agreements. Such limited continuing involvement is related to the Company’s undertaking to cooperate with HCRP in the event of litigation or a dispute related to the license agreements. Because the transaction was structured as a non-cancellable sale, the Company does not have significant continuing involvement in the generation of the cash flows due to HCRP and there are no guaranteed rates of return to HCRP, the Company recorded the total proceeds of $18.0 million as unearned revenue recognized under units-of-revenue method. The Company allocated the total proceeds between the two Royalty Sale Agreements based on the relative fair value of expected payments to be made to HCRP under the license agreements. The unearned revenue is being recognized as revenue over the life of the underlying license agreements under the "units-of-revenue" method. Under this method, amortization for a reporting period is calculated by computing a ratio of the allocated proceeds received from HCRP to the payments expected to be made by the licensees to HCRP over the term of the Acquisition Agreements, and then applying that ratio to the period’s cash payment. During the third quarter of 2018, the Shire product underlying the Dyax Corp. license agreement was approved, and the Company began recognizing revenue under the units-of-revenue method due to sales of the approved product.

The Company recognized $0.4 million and $0.3 million as revenue under units-of-revenue method under these arrangements during the three months ended March 31, 2021 and 2020, respectively.

As of March 31, 2021, the Company classified $1.5 million and $13.1 million as current and non-current unearned revenue recognized under units-of-revenue method, respectively. As of December 31, 2020, the current and non-current portion of the remaining unearned revenue recognized under units-of-revenue method was $1.5 million and $13.5 million, respectively.