On July 7, 2020, the Company entered into a collaboration agreement, or the Sanofi Agreement, with Sanofi, to co-develop drug candidates directed to two biological targets. Under the Sanofi Agreement, the Company granted to Sanofi a worldwide exclusive license to develop, manufacture and commercialize certain lead compounds generated during the collaboration directed against IRAK4, or Collaboration Target 1, and one additional undisclosed target in an undisclosed field of use, or Collaboration Target 2. Such license is exercisable on a collaboration target-by-collaboration target basis only after specified milestones. For compounds directed against IRAK4, the field of use includes diagnosis, treatment, cure, mitigation or prevention of any diseases, disorders or conditions, excluding oncology and immuno-oncology.

Pursuant to the Sanofi Agreement, the Company is responsible for discovery and preclinical research and conducting a Phase 1 clinical trial for at least one degrader directed against IRAK4 plus up to three backup degraders. With respect to both targets, Sanofi is responsible for development, manufacturing, and commercialization of product candidates after a specified development milestone occurs with respect to each collaboration candidate.

In addition, pursuant to the Sanofi Agreement, Sanofi will grant to the Company an exclusive option, or Opt-In Right, exercisable on a collaboration target-by-collaboration target basis that will include the right to (i) to fund 50% of the United States development costs for collaboration products directed against such target in the applicable field of use and (ii) share equally in the net profits and net losses of commercializing collaboration products directed against such target in the applicable field of use in the United States. In addition, if the Company exercises the Opt-In Right, Sanofi will grant to the Company an exclusive option, applicable to each collaboration target, which upon exercise will allow the Company to conduct certain co-promotion activities in the field in the United States.

The Sanofi Agreement, unless earlier terminated, will expire on a product-by-product basis on the date of expiration of all payment obligations under the Sanofi Agreement with respect to such product. The Company or Sanofi may terminate the agreement upon the other party’s material breach or insolvency or for certain patent challenges. In addition, Sanofi may terminate the Sanofi Agreement for convenience or for a material safety event upon advance prior written notice, and the Company may terminate the Sanofi Agreement with respect to any collaboration candidate if, following Sanofi’s assumption of responsibility for the development, commercialization or manufacturing of collaboration candidates with respect to a particular target, Sanofi ceases to exploit any collaboration candidates directed to such target for a specified period.

In consideration for the exclusive licenses granted to Sanofi under the Sanofi Agreement, Sanofi paid to the Company an upfront payment of $150.0 million. The Company will also be reimbursed for certain research activities for a certain backup degrader under the IRAK4 program as well as contract manufacturing costs for the lead 474 program, unless certain criteria are not met for an initial IRAK4 degrader. In addition to the upfront payment and the reimbursements, the Company is eligible to receive certain development milestone payments of up to $1.48 billion in the aggregate, of which more than $1.0 billion relates to the IRAK4 program, upon the achievement of certain developmental or regulatory events. The Company will be eligible to receive certain commercial milestone payments up to $700.0 million in the aggregate, of which $400.0 million relates to the IRAK4 program, which are payable upon the achievement of certain net sales thresholds. The Company will be eligible to receive tiered royalties for each program on net sales ranging from the high-single digits to high teens, subject to low-single digits upward adjustments in certain circumstances.

On November 15, 2022, we entered into an Amended and Restated Collaboration and License Agreement with Sanofi, or the Amended Sanofi Agreement, which amended the Original Sanofi Agreement to revise certain research terms and responsibilities set forth under the Original Sanofi Agreement. The Amended Sanofi Agreement also specifies details around the timing and number of Phase 2 trials required under the terms of the collaboration. The Amended Sanofi Agreement became effective on December 5, 2022.

Additionally with respect to Sanofi, on December 2, 2022, Sanofi provided the Company with written notice of its intention to advance the collaboration target 1 candidate, KT-474, into Phase 2 clinical trials. The Company is entitled to receive milestone payments upon the dosing of the first Phase 2 patient(s) per indication up to a specified number of indications as further set forth in the Amended Sanofi Agreement.

The Company analyzed the discovery and pre-clinical research activities as well as the exclusive license grants under the Sanofi Agreement and concluded that the arrangement was indicative of a vendor-customer relationship and would be accounted for under ASC 606.

The Company identified the following material promises under the arrangement: (1) research services for Collaboration Target 1, (2) research license for Collaboration Target 1, (3) exclusive license for Collaboration Target 1, (4) research services for Collaboration Target 2, (5) research license for Collaboration Target 2, (6) exclusive license for Collaboration Target 2, (7) option to extend the research term, and (8) optional research services during the development period.

The Company determined that Collaboration Targets 1 and 2 are distinct from each other. The research associated with degraders directed to each target is at different stages and the licensed field, should development activities be successful, are different from each other. As such, all promises associated with each target are considered distinct from promises associated with the other target.

The research and development services for each collaboration target were determined not to be distinct from the research license and the exclusive license and have been combined into a single performance obligation for each collaboration target. That is, two performance obligations were identified, the combined research services, research license and exclusive license for Collaboration Target 1 and the combined research services, research license and exclusive license for Collaboration Target 2. The exclusive license for each target is not distinct from the pre-clinical and clinical research and development services under the Sanofi Agreement, primarily due to the highly specialized nature of the research and novel technology involved with developing protein degraders – the pre-clinical activities and studies and first phase 1 clinical trial could not be conducted by another party in the manner required.

The option to extend the research term and optional research services during the development period were evaluated as material rights. The fees associated with each option are at or above the standalone selling price. As such, the underlying options are not performance obligations and fees associated with each option are excluded from the transaction price until the underlying option is exercised.

The Company determined the total transaction price to be $150.0 million, which consists solely of the upfront payment. All milestone payments and option payments are constrained as the achievement of such milestones are contingent upon the success of the underlying research and development activities and are generally outside the control of the Company. The reimbursement of costs for the IRAK4 backup degrader is also treated as constrained variable consideration as the criteria for reimbursement may not always be met, under which circumstances the Company would be responsible for the costs related to the backup degrader. Upon becoming unconstrained, the reimbursement consideration will be added to the transaction price and allocated to Collaboration Target 1.

The Company allocated the upfront payment to each performance obligation based on the relative standalone selling price, as follows:

The Company determined the allocation of the $150.0 million transaction price between Collaboration Target 1 and Collaboration Target 2 based on the value of the research and development for the programs from projected research and development costs for each collaboration target plus a developer’s profit and the total potential milestones for each collaboration target.

The Company recognizes revenue associated with each performance obligation as the research and development services are provided using an input method, according to costs incurred as related to the research and development activities for each individual program and the costs expected to be incurred in the future to satisfy that individual performance obligation. The transfer of control occurs over this time period and, in management’s judgment, is the best measure of progress towards satisfying each performance obligation. The amounts received that have not yet been recognized as revenue are deferred as a contract liability on the Company’s consolidated balance sheet and will be recognized over the remaining research and development period until the performance obligation is satisfied. Reimbursement consideration added to the transaction price will be recognized as revenue on the same pattern as Collaboration Target 1, with a cumulative catch-up upon becoming unconstrained. The performance obligations have not been fully satisfied as of June 30, 2023. In the three months ended June 30, 2023, the Company recognized $9.9 million in revenue under the Sanofi Agreement, of which $8.8 million was associated with Collaboration Target 1 and $1.1 million was associated with Collaboration Target 2. In the six months ended June 30, 2023, the Company recognized $17.6 million in revenue under the Sanofi Agreement, of which $15.9 million was associated with Collaboration Target 1 and $1.7 million was associated with Collaboration Target 2. In the three months ended June 30, 2022, the Company recognized $8.4 million in revenue under the Sanofi Agreement, of which $5.8 million was associated with Collaboration Target 1 and $2.6 million was associated with Collaboration Target 2. In the six months ended June 30, 2022, the Company recognized $15.0 million in revenue under the Sanofi Agreement, of which $10.0 million was associated with Collaboration Target 1 and $5.0 million was associated with Collaboration Target 2. Of the $17.6 million of revenue recognized in the six months ended June 30, 2023, $12.5 million was recognized from amounts that were recorded in deferred revenue as of December 31, 2022. The aggregate amount of the transaction price allocated to the Company’s unsatisfied performance obligations and recorded in deferred revenue at June 30, 2023 and December 31, 2022 is $44.7 million and $54.9 million, respectively. During the six months ended June 30, 2023, the Company received $5.9 million in cost reimbursement payments. No milestone or royalty payments have been

received under the Sanofi Agreement. As of June 30, 2023, the Company recorded a contract asset for unbilled accounts receivable of $4.1 million related to reimbursable research and development costs under the Sanofi Agreement for activities performed during the second quarter of 2023. As of June 30, 2023, the Company did not have any amounts recorded in accounts receivable under the Sanofi Agreement. The Company will recognize the deferred revenue related to the research and development services based on a cost input method, as described, over the remaining research term, which is a maximum of 2.5 years as of June 30, 2023.

Any consideration related to performance-based milestones will be recognized when the risk of probable reversal is resolved, at which point the Company shall adjust the transaction price determined for the agreement accordingly and recognize revenue on a cumulative-catch up basis, reallocating the revised arrangement consideration to the performance obligations. Any consideration related to sales milestone payments and royalties will be recognized when the related milestone events or sales occur and therefore are recognized at the later of when the related sales occur or the relevant performance obligation is satisfied. As part of its evaluation of constraining the milestones, the Company considered numerous factors, including the fact that the achievement of the research and development milestones are contingent upon the results of the underlying research and development activities and are thus outside of the control of the Company.

On May 9, 2019 (the “Effective Date”), the Company entered into a collaboration agreement (the “Vertex Agreement”) with Vertex to advance small molecule protein degraders against up to six targets. Under the Vertex Agreement, Vertex had the exclusive option to license the rights to the product candidates developed for the designated targets at which point Vertex would control development and commercialization. Pursuant to the Vertex Agreement, the Company was only responsible for discovery and preclinical research on the targets, and Vertex was responsible for development, manufacturing, and commercialization of the product candidates after it exercises its option to license. The initial research term of the collaboration was four (4) years, extendable for an additional one (1) year period upon mutual agreement by the parties and payment by Vertex of certain per-target fees.

The Company was eligible to receive up to $170.0 million in payments per target, including development, regulatory and commercial milestones as well as option exercise payments. In addition, Vertex iwas obligated to pay the Company tiered royalties on future net sales on any products that may result from the Vertex Agreement. None of the payments under the Vertex Agreement are refundable. The Company may also perform follow-on research for an optioned target upon Vertex’s request and at Vertex’s expense.

The term of the Vertex Agreement began on the Effective Date and expired upon the completion of the initial research term on May 9, 2023.

Vertex provided the Company with a non-refundable upfront payment of $50.0 million and purchased 3,059,695 shares of the Company’s Series B-1 Convertible Preferred Stock (the “Series B-1 Preferred Stock”) at $6.54 a share, pursuant to a separate, but simultaneously executed Share Purchase Agreement. The shares were purchased at a premium of $5.9 million, which was included in the transaction price and will be recognized as revenue over the period of performance. As a result of this purchase, Vertex was considered a related party. As of June 30, 2023, Vertex is no longer considered a related party.

The Company analyzed the joint research activities required under the Vertex Agreement and concluded that the arrangement was indicative of a vendor-customer relationship and would be accounted for under ASC 606.

The Company identified the following material promises under the arrangement: (1) the non-exclusive, royalty-free research license; (2) the research and development services to be performed on up to six targets; and (3) the option to license each of the targets for development, manufacturing, and commercialization efforts. The research and development services were determined not to be distinct from the research and development license and have been combined into a single performance obligation. The Company determined that the option to license the targets in the future was not priced at a discount, and that the option exercise fee for each target is at or above the standalone selling price for research at this stage of development; as such, the options and the underlying licenses are excluded from the performance obligation and the option exercise fees are excluded from the transaction price until the underlying option is exercised.

As part of its evaluation of constraining the research and development milestones, the Company considered numerous factors, including the fact that the achievement of the research and development milestones is contingent upon the results of the underlying research and development activities and is thus outside of the control of the Company.

At the commencement of the arrangement, two units of accounting were identified: the issuance of 3,059,695 shares of the Series B-1 Preferred Stock and the research activities the Company will perform over the Research Term. The Company determined the total transaction price to be $55.9 million, which consists of $5.9 million attributed to the premium from the shares of Series B-1 Preferred Stock sold to Vertex and the $50.0 million upfront payment. To determine the fair value of the Series B-1 Preferred Stock issued to

Vertex, the Company performed a valuation of the shares of the Company’s common and preferred stock, which took into consideration recent financings, and the Company’s recent development and future exit strategies, as well as a discount for lack of marketability.

The Company recognizes revenue associated with the performance obligation as the research and development services are provided using an input method, according to the costs incurred as related to the research and development activities on each program and the costs expected to be incurred in the future to satisfy the performance obligation. The transfer of control occurs over this time period and, in management’s judgment, is the best measure of progress towards satisfying the performance obligation. The Vertex collaboration agreement expired upon completion of the initial research term in May of 2023. Accordingly, the Company fully satisfied its performance obligation and recognized all remaining deferred revenue associated with the Vertex collaboration in during the three-month period ended June 30, 2023. During the three months ended June 30, 2023 and 2022, the Company recognized $6.6 million and $3.1 million, respectively, and during the six months ended June 30, 2023 and 2022, the Company recognized $8.4 million and $6.1 million, respectively, under the Vertex Agreement. All $8.4 million of revenue recognized in the six months ended June 30, 2023 was recognized from amounts that were recorded in deferred revenue as of December 31, 2022. There were no unsatisfied performance obligations as of June 30, 2023. The aggregate amount of the transaction price allocated to the Company’s unsatisfied performance obligation and recorded in deferred revenue December 31, 2022 is $0 and $8.4 million, respectively.

The following table presents the changes in accounts receivable, contract assets and contract liabilities for the six months ended June 30, 2023 (in thousands):


	Balance at December 31, 2022		Additions		Deductions			Balance at June 30, 2023
Accounts receivable and contract assets:
Billed receivables - Sanofi	$	—	$	5,857	$	(5,857	)	$	—
Unbilled receivables - Sanofi		2,537		7,442		(5,857	)		4,122
Total accounts receivable and contract assets	$	2,537	$	13,299	$	(11,714	)	$	4,122
Contract liabilities:
Deferred revenue - Vertex	$	8,399	$	—	$	(8,399	)	$	—
Deferred revenue - Sanofi		54,861		7,442		(17,580	)		44,723
Total contract liabilities	$	63,260	$	7,442	$	(25,979	)	$	44,723