0001193125-21-251551 | 6-K | XBRL Viewer

Print Document View Excel Document

Cover Page	6 Months Ended
Cover Page	Jun. 30, 2021
Cover [Abstract]
Document Type	6-K
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Entity Registrant Name	NUCANA PLC
Entity Central Index Key	0001709626
Current Fiscal Year End Date	--12-31

Unaudited Condensed Consolidated Statements of Operations - GBP (£) £ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Profit or loss [abstract]
Research and development expenses	£ (8,523)	£ (5,863)	£ (17,229)	£ (11,801)
Administrative expenses	(2,075)	(1,629)	(4,179)	(3,238)
Net foreign exchange (losses) gains	(109)	84	(786)	2,211
Operating loss	(10,707)	(7,408)	(22,194)	(12,828)
Finance income	35	64	59	208
Loss before tax	(10,672)	(7,344)	(22,135)	(12,620)
Income tax credit	1,585	1,283	3,287	2,593
Loss for the period	£ (9,087)	£ (6,061)	£ (18,848)	£ (10,027)
Basic and diluted loss per share	£ (0.17)	£ (0.19)	£ (0.36)	£ (0.31)

Unaudited Condensed Consolidated Statements of Comprehensive Loss - GBP (£) £ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of comprehensive income [abstract]
Loss for the period	£ (9,087)	£ (6,061)	£ (18,848)	£ (10,027)
Items that may be reclassified subsequently to profit or loss:
Exchange differences on translation of foreign operations	(1)	1	(4)	22
Other comprehensive (loss) income for the period	(1)	1	(4)	22
Total comprehensive loss for the period	(9,088)	(6,060)	(18,852)	(10,005)
Attributable to:
Equity holders of the Company	£ (9,088)	£ (6,060)	£ (18,852)	£ (10,005)

- Definition

The amount of change in equity resulting from transactions and other events, other than those changes resulting from transactions with owners in their capacity as owners.

+ References + Details

- Definition

The total of income less expenses from continuing and discontinued operations, excluding the components of other comprehensive income. [Refer: Other comprehensive income]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 7
-IssueDate 2020-01-01
-Paragraph 18
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=7&code=ifrs-tx-2020-en-r&anchor=para_18_b&doctype=Standard
-URIDate 2020-01-01

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 1
-IssueDate 2020-01-01
-Paragraph 24
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2020-en-r&anchor=para_24_b&doctype=Standard
-URIDate 2020-01-01

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 1
-IssueDate 2020-01-01
-Paragraph 32
-Subparagraph a
-Clause ii
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=1&code=ifrs-tx-2020-en-r&anchor=para_32_a_ii&doctype=Standard
-URIDate 2020-01-01

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2020-01-01
-Paragraph 28
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_28_b&doctype=Standard
-URIDate 2020-01-01

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Note Effective on first application of IFRS 9
-Name IFRS
-Number 4
-IssueDate 2020-01-01
-Paragraph 39L
-Subparagraph e
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=4&code=ifrs-tx-2020-en-b&anchor=para_39L_e&doctype=Standard
-URIDate 2020-01-01

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 8
-IssueDate 2020-01-01
-Paragraph 23
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=8&code=ifrs-tx-2020-en-r&anchor=para_23&doctype=Standard
-URIDate 2020-01-01

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Name IFRS
-Number 12
-IssueDate 2020-01-01
-Paragraph B10
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=12&code=ifrs-tx-2020-en-r&anchor=para_B10_b&doctype=Appendix&subtype=B
-URIDate 2020-01-01

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 106
-Subparagraph d
-Clause i
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_106_d_i&doctype=Standard
-URIDate 2020-01-01

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Note Effective 2021-01-01
-Name IFRS
-Number 17
-IssueDate 2020-01-01
-Paragraph 113
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IFRS&num=17&code=ifrs-tx-2020-en-r&anchor=para_113_b&doctype=Standard
-URIDate 2020-01-01

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name IAS
-Number 1
-IssueDate 2020-01-01
-Paragraph 81A
-Subparagraph a
-URI http://eifrs.ifrs.org/eifrs/xifrs-link?type=IAS&num=1&code=ifrs-tx-2020-en-r&anchor=para_81A_a&doctype=Standard
-URIDate 2020-01-01

+ Details

Unaudited Condensed Consolidated Statements of Financial Position - GBP (£) £ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Non-current assets
Intangible assets	£ 4,814	£ 4,753
Property, plant and equipment	1,038	1,189
Deferred tax asset	37	44
Total non-current assets	5,889	5,986
Current assets
Prepayments, accrued income and other receivables	4,198	4,628
Current income tax receivable	8,815	9,822
Cash and cash equivalents	73,421	87,356
Total current assets	86,434	101,806
Total assets	92,323	107,792
Capital and reserves
Share capital and share premium	143,135	142,937
Other reserves	69,214	66,887
Accumulated deficit	(128,158)	(110,594)
Total equity attributable to equity holders of the Company	84,191	99,230
Non-current liabilities
Provisions	46	46
Lease liabilities	231	367
Total non-current liabilities	277	413
Current liabilities
Trade payables	1,697	2,257
Payroll taxes and social security	166	177
Accrued expenditure	5,717	5,437
Lease liabilities	275	278
Total current liabilities	7,855	8,149
Total liabilities	8,132	8,562
Total equity and liabilities	£ 92,323	£ 107,792

Unaudited Condensed Consolidated Statements of Changes In Equity - GBP (£) £ in Thousands	Total	Share Capital [member]	Share Premium [member]	Own Share Reserve [member]	Share Option Reserve [member]	Foreign Currency Translation Reserve [member]	Capital Reserve [member]	Accumulated Deficit [member]
Beginning balance at Dec. 31, 2019	£ 63,522	£ 1,299	£ 79,541	£ (339)	£ 20,620	£ (10)	£ 42,466	£ (80,055)
Loss for the period	(10,027)							(10,027)
Other comprehensive income (loss) for the year	22					22
Total comprehensive loss for the period	(10,005)					22		(10,027)
Share-based payments	1,669				1,669
Exercise of share options	15	1	14		(68)			68
Issue of share capital	2,033	18	2,015
Share issue expenses	(105)		(105)
Ending balance at Jun. 30, 2020	57,129	1,318	81,465	(339)	22,221	12	42,466	(90,014)
Beginning balance at Dec. 31, 2020	99,230	2,047	140,890	(339)	24,782	(22)	42,466	(110,594)
Loss for the period	(18,848)							(18,848)
Other comprehensive income (loss) for the year	(4)					(4)
Total comprehensive loss for the period	(18,852)					(4)		(18,848)
Share-based payments	3,615				3,615
Exercise of share options	198	39	159		(1,088)			1,088
Lapse of share options					(196)			196
Ending balance at Jun. 30, 2021	£ 84,191	£ 2,086	£ 141,049	£ (339)	£ 27,113	£ (26)	£ 42,466	£ (128,158)

- Definition

The amount of change in equity resulting from transactions and other events, other than those changes resulting from transactions with owners in their capacity as owners.

+ References + Details

- Definition

The amount of residual interest in the assets of the entity after deducting all its liabilities.

+ References + Details

- Definition

The total of income less expenses from continuing and discontinued operations, excluding the components of other comprehensive income. [Refer: Other comprehensive income]

+ References

+ Details

Unaudited Condensed Consolidated Statements of Cash Flows - GBP (£) £ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities
Loss for the period	£ (18,848)	£ (10,027)
Adjustments for:
Income tax credit	(3,287)	(2,593)
Amortization and depreciation	444	440
Finance income	(59)	(208)
Interest expense on lease liabilities	10	14
Share-based payments	3,615	1,669
Net foreign exchange losses (gains)	759	(2,252)
Cash flows from (used in) operations before changes in working capital	(17,366)	(12,957)
Movements in working capital:
Decrease in prepayments, accrued income and other receivables	424	802
Decrease in trade payables	(560)	(484)
Increase in payroll taxes, social security and accrued expenditure	269	840
Movements in working capital	133	1,158
Cash used in operations	(17,233)	(11,799)
Net income tax received	4,302	4,152
Net cash used in operating activities	(12,931)	(7,647)
Cash flows from investing activities
Interest received	58	279
Payments for property, plant and equipment	(37)	(14)
Payments for intangible assets	(319)	(804)
Net cash used in investing activities	(298)	(539)
Cash flows from financing activities
Payments of lease liabilities	(148)	(148)
Proceeds from issue of share capital – exercise of share options	198	15
Proceeds from issue of share capital	0	2,033
Share issue expenses		(105)
Net cash from financing activities	50	1,795
Net decrease in cash and cash equivalents	(13,179)	(6,391)
Cash and cash equivalents at beginning of period	87,356	51,962
Effect of exchange rate changes on cash and cash equivalents	(756)	2,229
Cash and cash equivalents at end of period	£ 73,421	£ 47,800

General Information

6 Months Ended

Jun. 30, 2021

Disclosure Of General Information About Financial Statements [Abstract]

General information

1. General information

NuCana plc (“NuCana” or the “Company”) is a clinical-stage biopharmaceutical company developing a portfolio of new medicines to treat cancer. NuCana is harnessing the power of phosphoramidate chemistry to generate new medicines called ProTides. These compounds have the potential to improve cancer treatment by enhancing the efficacy and safety of several current standards of care.

The Company has ordinary shares in the form of American Depositary Shares (“ADSs”) registered with the US Securities and Exchange Commission (the “SEC”) and has been listed on The Nasdaq Global Select Market (“Nasdaq”) since October 2, 2017. The Company is incorporated in England and Wales

and

domiciled
in the United Kingdom. The Company’s registered office is located at 77/78 Cannon Street, London EC4N 6AF, United Kingdom and its principal place of business is located at 3 Lochside Way, Edinburgh, EH12 9DT, United Kingdom.

The Company has three wholly owned subsidiaries, NuCana, Inc., NuCana Limited and NuCana BioMed Trustee Company Limited (together referred to as the “Group”).

The financial information presented in these unaudited condensed consolidated financial statements does not constitute the Group’s statutory accounts within the meaning of section 434 of the U.K. Companies Act 2006

The Group’s statutory accounts for the year ended December 31, 2020 have been reported on by the Company’s auditor and delivered to the Registrar of Companies. The report of the auditor was (i) unqualified, (ii) did not include a reference to any matters to which the auditors drew attention by way of emphasis without qualifying their report, and (iii) did not contain a statement under section 498 (2) or (3) of the Companies Act 2006.

Significant Accounting Policies

6 Months Ended

Jun. 30, 2021

Disclosure Of Summary Of Significant Accounting Policies [Abstract]

Significant accounting policies

2. Significant accounting policies

Basis of preparation

The unaudited condensed consolidated financial statements (the “financial statements”) for the three months and six months ended June 30, 2021 have been prepared in accordance with International Accounting Standard 34, “

Interim Financial Reporting”

(“IAS 34”). The significant accounting policies and methods of computation applied in the preparation of the financial statements are consistent with those applied in the Company’s annual financial statements for the year ended December 31, 2020. No new standards, amendments or interpretations have had an impact on the financial statements for the three months and six months ended June 30, 2021. The financial statements comprise the financial statements of the Group at June 30, 2021. The financial statements are presented in pounds sterling, which is also the Company’s functional currency. All values are rounded to the nearest thousand, except where otherwise indicated.

The financial statements do not include all the information and disclosures required in the annual financial statements, and should be read in conjunction with the Company’s annual financial statements for the year ended December 31, 2020.

In the opinion of management, these unaudited condensed consolidated financial statements include all normal recurring adjustments necessary for a fair statement of the results of operations, financial position and cash flows. The results of operations for the three months and six months ended June 30, 2021 are not necessarily indicative of the results that can be expected for the Company’s fiscal year ending December 31, 2021.

Going concern

In common with many companies in the biopharmaceutical sector, the Company incurs significant expenditure in its early years as it researches and develops its potential products for market.

The Company’s board of directors, having reviewed the operating budgets and development plans, considers that the Company has adequate resources to continue in operation for the foreseeable future. The board of directors is therefore satisfied that it is appropriate to adopt the going concern basis of accounting in preparing the financial statements. The Company believes that its cash and cash equivalents of £73.4 million at June 30, 2021 will be sufficient to fund its current operating plan for at least the next 12 months. Further, the directors have conducted an assessment of the impact of

COVID-19

on the going concern status of the Company and have concluded that it will not have a significant negative impact on the cash outflows of the Company over the period assessed for going concern purposes

As the Company continues to incur losses, the transition to profitability is dependent upon the successful development, approval and commercialization of its product candidates and achieving a level of revenues adequate to support its cost structure. The Company may never achieve profitability, and unless and until it does, it will continue to need to raise additional capital. There can be no assurances, however, that additional funding will be available on acceptable terms.

COVID-19

In response to the spread of

COVID-19,

all of the Company’s offices have been closed with employees continuing their work outside of the offices and the Company has restricted

on-site

staff access to only those required to execute their job responsibilities.

During the early months of the pandemic the Company announced that there was some temporary interruption to the enrollment of new patients in the Company’s ongoing clinical trials. In May 2020, the Company further announced that enrollment of new patients in the Company’s clinical trials

had

re-commenced.

While
the Company continues to evaluate the impact of

COVID-19

on its operations, the Company believes that this pandemic will inevitably cause some delays to the timing of initiation and completion of its clinical trials. The Company is continuing to monitor the impact of

COVID-19.

COVID-19

has had no impact on the judgements and estimates used in the preparation of these financial statements.

Judgements and estimates

The accounting estimates and judgements made by management in applying the Group’s accounting policies that have the most significant effect on the amounts included within these financial statements, were the same as those that applied to the annual financial statements for the year ended December 31, 2020.

Income Tax

6 Months Ended

Jun. 30, 2021

Major Components Of Tax Expense Income [Abstract]

Income tax

3. Income tax


	For the Three Months Ended June 30,						For the Six Months Ended June 30,
	2021			2020			2021			2020
	(in thousands)						(in thousands)
	£			£			£			£
Current tax:
In respect of current period U.K.		1,588			1,289			3,294			2,604
In respect of current period U.S.		—			(1	)		—			(1	)

		1,588			1,288			3,294			2,603
Deferred tax:
In respect of current period U.S.		(3	)		(5	)		(7	)		(9	)
In respect of prior period U.S.		—			—			—			(1	)

Income tax credit		1,585			1,283			3,287			2,593

The income tax credit recognized primarily represents the U.K. research and development tax credit. In the United Kingdom, the Company is able to surrender some of its losses for a cash rebate of up to 33.35% of expenditure related to eligible research and development projects.


	June 30, 2021		December 31, 2020
	(in thousands)
	£		£
Current income tax receivable
U.K. tax		8,811		9,818
U.S. tax		4		4

		8,815		9,822

Deferred tax asset
U.S. deferred tax asset		37		44

Basic and Diluted Loss Per Share

6 Months Ended

Jun. 30, 2021

Earnings Per Share [Abstract]

Basic and diluted loss per share

4. Basic and diluted loss per share


	For the Three Months Ended June 30,						For the Six Months Ended June 30,
	2021			2020			2021			2020
	(in thousands, except per share data)
	£			£			£			£
Loss for the period		(9,087	)		(6,061	)		(18,848	)		(10,027	)


Basic and diluted weighted average number of shares		52,162			32,668			51,907			32,573
	£			£			£			£
Basic and diluted loss per share		(0.17	)		(0.19	)		(0.36	)		(0.31	)

Basic loss per share is calculated by dividing the loss for the period attributable to the equity holders of the Company by the weighted average number of shares outstanding during the period.

The potential shares issued through equity settled transactions were considered to be anti-dilutive as they would have decreased the loss per share and were therefore excluded from the calculation of diluted loss per share.

Intangible Assets

6 Months Ended

Jun. 30, 2021

Disclosure Of Intangible Assets [Abstract]

Intangible assets

5. Intangible assets

Intangible assets comprise patents with a carrying value of £4.7 million as of June 30, 2021 (as of December 31, 2020: £4.6 million) and computer software with a carrying value of £0.1 million as of June 30, 2021 (as of December 31, 2020: £0.2 million).

During the six months ended June 30, 2021, the Company acquired intangible assets with a cost of £0.3 million in relation to patents. There were no disposals of intangible assets in the six months ended June 30, 2021.

Cash and Cash Equivalents

6 Months Ended

Jun. 30, 2021

Cash And Cash Equivalents [Abstract]

Cash and cash equivalents

6. Cash and cash equivalents


	June 31, 2021		December 31, 2020
	(in thousands)
	£		£
Cash and cash equivalents		73,421		87,356

Cash and cash equivalents comprise cash at banks with maturity terms of three months or less, and is subject to insignificant risk of changes in value. Cash at banks earns interest at fixed or variable rates based on the terms agreed for each account.

Share-based Payments

6 Months Ended

Jun. 30, 2021

Disclosure Of Terms And Conditions Of Sharebased Payment Arrangement [Abstract]

Share-based payments

7. Share-based payments

The Company has six share-based payment plans for employees, directors and consultants. The share options granted will be settled in equity. Options granted under each of the six plans have a maximum life of 10 years. If the Company determines, and at its discretion, an arrangement may be made under the 2020 Long-Term Incentive Plan to substitute the right to acquire shares with a cash alternative of equivalent value.

As detailed in the table below, during the six months ended June 30, 2021, 1,501,663 share options were granted under the 2020 Long-Term Incentive Plan (six months ended June 30, 2020: 2,186,780 share options granted under the 2016 Share Option Scheme). Options granted under this plan will vest if the option holder remains under respective contract of employment or contract of service for the agreed vesting period. The share options granted in the period will vest over a period of up to four years.

The fair values of options granted were determined using the Black-Scholes model that takes into account factors specific to the share incentive plan such as the assumption that the options are exercised at a point in time of up to two years after vesting. This has been incorporated into the measurement by means of actuarial modelling. As NuCana plc was unlisted until October 2, 2017, it is not possible to derive historical volatility from the Company’s ADSs prior to October 2017. For options with an estimated life of greater than three years, the underlying expected volatility was determined by using the average of the historical volatility of similar listed entities as a proxy. Options granted with an estimated life of three years or less, have been valued using the Company’s own historical volatility rates.


	Options granted on

	January 13, 2021			February 10, 2021			February 10, 2021			February 10, 2021
Vesting dates		January 13, 2022			February 10, 2022			February 10, 2022			February 10, 2022
		January 13, 2023			February 10, 2023			February 10, 2023			February 10, 2023
		January 13, 2024			February 10, 2024			February 10, 2024			February 10, 2024
		January 13, 2025			February 10, 2025			February 10, 2025			February 10, 2025
Volatility		81.42	%		81.45	%		87.66	%		83.86	%
Dividend yield		0	%		0	%		0	%		0	%
Risk-free investment rate		0.01	%		0.11	%		0.01	%		0.05	%
Fair value of option at grant date	£	2.37		£	2.74		£	4.49		£	4.49
Fair value of share at grant date	£	3.92		£	4.53		£	4.53		£	4.53
Exercise price at date of grant	£	3.92		£	4.53		£	0.04		£	0.04
Lapse date		January 13, 2031			February 10, 2031			—			February 10, 2031
Expected option life (years)		4.5			4.5			2.5			3.5
Number of options granted		200,000			872,775			91,888			337,000

For the three months ended June 30, 2021, the Company has recognized £1.8 million of share-based payment expense in the statement of operations (three months ended June 30, 2020: £0.8 million). For the six months ended June 30, 2021, the Company has recognized £3.6 million of share-based payment expense in the statement of operations (six months ended June 30, 2020: £1.7 million).

Share Capital and Share Premium

6 Months Ended

Jun. 30, 2021

Disclosure Of Classes Of Share Capital [Abstract]

Share capital and share premium

8. Share capital and share premium


	June 30, 2021		December 31, 2020
	(in thousands)
	£		£
Share capital		2,086		2,047
Share premium		141,049		140,890

		143,135		142,937


	June 30, 2021		December 31, 2020
	Number (in thousands)
Issued share capital comprises:
Ordinary shares of £0.04 each		52,162		51,175


	Number of shares		Share capital		Share premium
	(in thousands)
			£		£
Fully paid shares:
Balance at December 31, 2020		51,175		2,047		140,890
Issue of shares on exercise of options		987		39		159

Balance at June 30, 2021		52,162		2,086		141,049

Contingent Liabilities

6 Months Ended

Jun. 30, 2021

Disclosure Of Contingent Liabilities [Abstract]

Contingent liabilities

9. Contingent liabilities

Under its U.K. share-based payment

plans

, the Company granted unapproved share options that have fully vested. If and when these share options are exercised, the Company will be liable for the Employer Class 1 National Insurance payable to HMRC in the United Kingdom. This contingent liability will be determined based on the market value of the shares on exercise less the exercise price paid by the option holders, at the prevailing rate of Employer National Insurance (currently 13.8%). Based on the closing price of the Company’s ADSs on the Nasdaq Global Select Market on June 30, 2021, the last trading day of the period to which these financial statements relate, and assuming full exercise of all outstanding and vested unapproved share options on that date, the Employer National Insurance contingent liability would have been £0.5 million (December 31, 2020: £0.8 million).

Events After the Reporting Period

6 Months Ended

Jun. 30, 2021

Events After Reporting Period [Abstract]

Events after the reporting period

10. Events after the reporting period

In April 2021, the Company initiated legal proceedings against Gilead Sciences Ireland UC and Gilead Sciences GmbH for patent infringement in Germany. In June 2021, the Company was requested by the court to provide the defendants with a security of €3.0 million (£2.6 million) to cover the legal costs of the defendants in the event that the Company is unsuccessful in the final outcome of the legal proceedings.

After the end of the reporting period the Company provided the security in accordance with the court order by depositing €3.0 million with the court. The extent to which the sum deposited will be reimbursed to the Company is dependent on a range of potential outcomes, and the timing of those outcomes, with respect to the patent infringement litigation in Germany, which is currently indeterminable.

Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2021

Disclosure Of Summary Of Significant Accounting Policies [Abstract]

Basis of preparation

Interim Financial Reporting”

Going concern

In common with many companies in the biopharmaceutical sector, the Company incurs significant expenditure in its early years as it researches and develops its potential products for market.

COVID-19

In response to the spread of

COVID-19,

all of the Company’s offices have been closed with employees continuing their work outside of the offices and the Company has restricted

on-site

staff access to only those required to execute their job responsibilities.

had

re-commenced.

While
the Company continues to evaluate the impact of

COVID-19

COVID-19.

COVID-19

has had no impact on the judgements and estimates used in the preparation of these financial statements.

Judgements and estimates

Income Tax (Tables)

6 Months Ended

Jun. 30, 2021

Major Components Of Tax Expense Income [Abstract]

Schedule of Major Components of Income Tax


	For the Three Months Ended June 30,						For the Six Months Ended June 30,
	2021			2020			2021			2020
	(in thousands)						(in thousands)
	£			£			£			£
Current tax:
In respect of current period U.K.		1,588			1,289			3,294			2,604
In respect of current period U.S.		—			(1	)		—			(1	)

		1,588			1,288			3,294			2,603
Deferred tax:
In respect of current period U.S.		(3	)		(5	)		(7	)		(9	)
In respect of prior period U.S.		—			—			—			(1	)

Income tax credit		1,585			1,283			3,287			2,593


	June 30, 2021		December 31, 2020
	(in thousands)
	£		£
Current income tax receivable
U.K. tax		8,811		9,818
U.S. tax		4		4

		8,815		9,822

Deferred tax asset
U.S. deferred tax asset		37		44

Basic and Diluted Loss Per Share (Tables)

6 Months Ended

Jun. 30, 2021

Earnings Per Share [Abstract]

Schedule of Basic and Diluted Loss Per Share


	For the Three Months Ended June 30,						For the Six Months Ended June 30,
	2021			2020			2021			2020
	(in thousands, except per share data)
	£			£			£			£
Loss for the period		(9,087	)		(6,061	)		(18,848	)		(10,027	)


Basic and diluted weighted average number of shares		52,162			32,668			51,907			32,573
	£			£			£			£
Basic and diluted loss per share		(0.17	)		(0.19	)		(0.36	)		(0.31	)

Cash and Cash Equivalents (Tables)

6 Months Ended

Jun. 30, 2021

Cash And Cash Equivalents [Abstract]

Schedule of Cash and Cash Equivalents


	June 31, 2021		December 31, 2020
	(in thousands)
	£		£
Cash and cash equivalents		73,421		87,356

Share-based Payments (Tables)

6 Months Ended

Jun. 30, 2021

Text block [abstract]

Summary of Principal Assumptions Used for Valuation of Share Options


	Options granted on

	January 13, 2021			February 10, 2021			February 10, 2021			February 10, 2021
Vesting dates		January 13, 2022			February 10, 2022			February 10, 2022			February 10, 2022
		January 13, 2023			February 10, 2023			February 10, 2023			February 10, 2023
		January 13, 2024			February 10, 2024			February 10, 2024			February 10, 2024
		January 13, 2025			February 10, 2025			February 10, 2025			February 10, 2025
Volatility		81.42	%		81.45	%		87.66	%		83.86	%
Dividend yield		0	%		0	%		0	%		0	%
Risk-free investment rate		0.01	%		0.11	%		0.01	%		0.05	%
Fair value of option at grant date	£	2.37		£	2.74		£	4.49		£	4.49
Fair value of share at grant date	£	3.92		£	4.53		£	4.53		£	4.53
Exercise price at date of grant	£	3.92		£	4.53		£	0.04		£	0.04
Lapse date		January 13, 2031			February 10, 2031			—			February 10, 2031
Expected option life (years)		4.5			4.5			2.5			3.5
Number of options granted		200,000			872,775			91,888			337,000

Share Capital and Share Premium (Tables)

6 Months Ended

Jun. 30, 2021

Disclosure Of Classes Of Share Capital [Abstract]

Summary of Share Capital and Share Premium


	June 30, 2021		December 31, 2020
	(in thousands)
	£		£
Share capital		2,086		2,047
Share premium		141,049		140,890

		143,135		142,937


	June 30, 2021		December 31, 2020
	Number (in thousands)
Issued share capital comprises:
Ordinary shares of £0.04 each		52,162		51,175

Summary of Movement in the Share Capital


	Number of shares		Share capital		Share premium
	(in thousands)
			£		£
Fully paid shares:
Balance at December 31, 2020		51,175		2,047		140,890
Issue of shares on exercise of options		987		39		159

Balance at June 30, 2021		52,162		2,086		141,049

General Information - Additional Information (Detail)	6 Months Ended
General Information - Additional Information (Detail)	Jun. 30, 2021 Subsidiary
Disclosure Of General Information About Financial Statements [Abstract]
Description of nature of entity's operations	clinical-stage biopharmaceutical company developing a portfolio of new medicines to treat cancer
Name of reporting entity	NuCana plc
Domicile of entity	United Kingdom
Country of incorporation	England and Wales
Number of subsidiaries	3
Name of subsidiary	NuCana, Inc., NuCana Limited and NuCana BioMed Trustee Company Limited

Significant Accounting Policies - Additional Information (Detail) - GBP (£) £ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Disclosure Of Summary Of Significant Accounting Policies [Abstract]
Cash and cash equivalents	£ 73,421	£ 87,356	£ 47,800	£ 51,962

Income Tax - Schedule of Major Components of Income Tax Credit (Detail) - GBP (£) £ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Current tax:
Total current tax	£ 1,588	£ 1,288	£ 3,294	£ 2,603
Deferred tax:
Income tax credit	1,585	1,283	3,287	2,593
U.K. [member]
Current tax:
In respect of current period	1,588	1,289	3,294	2,604
U.S. [member]
Current tax:
In respect of current period		(1)		(1)
Deferred tax:
In respect of current period	£ (3)	£ (5)	£ (7)	(9)
In respect of prior period				£ (1)

- Definition

The aggregate amount included in the determination of profit (loss) for the period in respect of current tax and deferred tax. [Refer: Current tax expense (income); Deferred tax expense (income)]

+ References + Details

Income Tax - Additional Information (Detail)	6 Months Ended
Income Tax - Additional Information (Detail)	Jun. 30, 2021
U.K. [member]
Disclosure of temporary difference, unused tax losses and unused tax credits [line items]
Percentage of losses surrendered for R&D tax credit	33.35%

Income Tax - Schedule of Major Components of Income Tax Assets (Detail) - GBP (£) £ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current income tax receivable
Current income tax receivable	£ 8,815	£ 9,822
Deferred tax asset
Deferred tax asset	37	44
U.K. [member]
Current income tax receivable
Current income tax receivable	8,811	9,818
U.S. [member]
Current income tax receivable
Current income tax receivable	4	4
Deferred tax asset
Deferred tax asset	£ 37	£ 44

Basic and Diluted Loss per Share - Schedule of Basic and Diluted Loss Per Share (Detail) - GBP (£) £ / shares in Units, £ in Thousands, shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Loss for the period	£ (9,087)	£ (6,061)	£ (18,848)	£ (10,027)
Basic and diluted weighted average number of shares	52,162	32,668	51,907	32,573
Basic and diluted loss per share	£ (0.17)	£ (0.19)	£ (0.36)	£ (0.31)

- Definition

The total of income less expenses from continuing and discontinued operations, excluding the components of other comprehensive income. [Refer: Other comprehensive income]

+ References

+ Details

Intangible Assets - Additional Information (Detail) - GBP (£) £ in Thousands	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Disclosure of detailed information about intangible assets [line items]
Intangible assets, carrying value	£ 4,814	£ 4,753
Patents [member]
Disclosure of detailed information about intangible assets [line items]
Intangible assets, carrying value	4,700	4,600
Intangible assets, acquired	300
Computer Software [member]
Disclosure of detailed information about intangible assets [line items]
Intangible assets, carrying value	£ 100	£ 200

Cash and Cash Equivalents - Schedule of Detailed Information About Cash and Cash Equivalents (Detail) - GBP (£) £ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	£ 73,421	£ 87,356	£ 47,800	£ 51,962

Share-based Payments - Additional Information (Details) £ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021 GBP (£)	Jun. 30, 2020 GBP (£)	Jun. 30, 2021 GBP (£) shares	Jun. 30, 2020 GBP (£) shares
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share-based payment expense \| £	£ 1.8	£ 0.8	£ 3.6	£ 1.7
Long-Term Incentive Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of share options granted in share-based payment arrangement \| shares			1,501,663	2,186,780
Share options granted, vesting period			4 years

Share Based Payments - Summary of Principal Assumptions used for Valuation of Share Options (Detail) - 6 months ended Jun. 30, 2021 - 2020 Share Options [member]	GBP (£) shares Subsidiary yr £ / shares	GBP (£) shares Subsidiary yr $ / shares
Grant Date June 10, 2020 [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Lapse date	Jan. 13, 2031	Jan. 13, 2031
Grant Date January 13, 2021 [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	81.42%	81.42%
Dividend yield	0.00%	0.00%
Risk-free investment rate	0.01%	0.01%
Fair value of option at grant date \| £	£ 2,370	£ 2,370
Fair value of share at grant date	£ 3.92
Exercise price at date of grant	£ 3.92
Expected option life (years) \| yr	4.5	4.5
Number of options granted \| shares	200,000	200,000
Grant Date January 13, 2021 [Member] \| Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 13, 2022	Jan. 13, 2022
Grant Date January 13, 2021 [Member] \| Vesting Dates Two [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 13, 2023	Jan. 13, 2023
Grant Date January 13, 2021 [Member] \| Vesting Dates Three [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 13, 2024	Jan. 13, 2024
Grant Date January 13, 2021 [Member] \| Vesting Dates Four [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Jan. 13, 2025	Jan. 13, 2025
Grant Date February 10, 2021 [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	81.45%	81.45%
Dividend yield	0.00%	0.00%
Risk-free investment rate	0.11%	0.11%
Fair value of option at grant date \| £	£ 2,740	£ 2,740
Fair value of share at grant date	£ 4.53
Exercise price at date of grant	£ 4.53
Lapse date	Feb. 10, 2031	Feb. 10, 2031
Expected option life (years) \| yr	4.5	4.5
Number of options granted \| shares	872,775	872,775
Grant Date February 10, 2021 [Member] \| Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2022	Feb. 10, 2022
Grant Date February 10, 2021 [Member] \| Vesting Dates Two [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2023	Feb. 10, 2023
Grant Date February 10, 2021 [Member] \| Vesting Dates Three [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2024	Feb. 10, 2024
Grant Date February 10, 2021 [Member] \| Vesting Dates Four [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2025	Feb. 10, 2025
Grant Date February 10, 2021 One [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	87.66%	87.66%
Dividend yield	0.00%	0.00%
Risk-free investment rate	0.01%	0.01%
Fair value of option at grant date \| £	£ 4,490	£ 4,490
Fair value of share at grant date	£ 4.53
Exercise price at date of grant	£ 0.04
Expected option life (years) \| yr	2.5	2.5
Number of options granted \| shares	91,888	91,888
Grant Date February 10, 2021 One [Member] \| Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2022	Feb. 10, 2022
Grant Date February 10, 2021 One [Member] \| Vesting Dates Two [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2023	Feb. 10, 2023
Grant Date February 10, 2021 One [Member] \| Vesting Dates Three [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2024	Feb. 10, 2024
Grant Date February 10, 2021 One [Member] \| Vesting Dates Four [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2025	Feb. 10, 2025
Grant Date February 10, 2021 Two [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Volatility	83.86%	83.86%
Dividend yield	0.00%	0.00%
Risk-free investment rate	0.05%	0.05%
Fair value of option at grant date \| £	£ 4,490	£ 4,490
Fair value of share at grant date \| $ / shares		£ 4.53
Exercise price at date of grant \| $ / shares		£ 0.04
Lapse date	Feb. 10, 2031	Feb. 10, 2031
Expected option life (years) \| yr	3.5	3.5
Number of options granted \| Subsidiary	337,000	337,000
Grant Date February 10, 2021 Two [Member] \| Vesting Dates One [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2022	Feb. 10, 2022
Grant Date February 10, 2021 Two [Member] \| Vesting Dates Two [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2023	Feb. 10, 2023
Grant Date February 10, 2021 Two [Member] \| Vesting Dates Three [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2024	Feb. 10, 2024
Grant Date February 10, 2021 Two [Member] \| Vesting Dates Four [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting dates	Feb. 10, 2025	Feb. 10, 2025

Share Capital and Share Premium - Summary of Share Capital and Share Premium (Detail) - GBP (£) £ in Thousands, shares in Thousands	Jun. 30, 2021	Dec. 31, 2020
Disclosure Of Classes Of Share Capital [Abstract]
Share capital	£ 2,086	£ 2,047
Share premium	141,049	140,890
Share capital and share premium	£ 143,135	£ 142,937
Ordinary shares of £0.04 each	52,162	51,175

Share Capital and Share Premium - Summary of Share Capital and Share Premium (Parenthetical) (Detail) - £ / shares	Jun. 30, 2021	Dec. 31, 2020
Ordinary shares [member]
Disclosure of classes of share capital [line items]
Par value per share	£ 0.04	£ 0.04

Share Capital and Share Premium - Summary of Movement in the Share Capital (Detail) £ in Thousands, shares in Thousands	6 Months Ended
	Jun. 30, 2021 GBP (£) shares	Jun. 30, 2020 GBP (£)
Disclosure of classes of share capital [line items]
Beginning balance, Shares \| shares	51,175
Beginning balance	£ 99,230	£ 63,522
Issue of shares on exercise of options \| shares	987
Issue of shares on exercise of options	£ 198	15
Ending balance, Shares \| shares	52,162
Ending balance	£ 84,191	57,129
Share Capital [member]
Disclosure of classes of share capital [line items]
Beginning balance	2,047	1,299
Issue of shares on exercise of options	39	1
Ending balance	2,086	1,318
Share Premium [member]
Disclosure of classes of share capital [line items]
Beginning balance	140,890	79,541
Issue of shares on exercise of options	159	14
Ending balance	£ 141,049	£ 81,465

- Definition

The amount of residual interest in the assets of the entity after deducting all its liabilities.

+ References + Details

Contingent Liabilities - Additional Information (Detail) - GBP (£) £ in Millions	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Disclosure Of Contingent Liabilities [Abstract]
Prevailing rate of employer national insurance	13.80%
Employer national insurance contingent liability	£ 0.5	£ 0.8

Events After the Reporting Period - Additional Information (Detail) € in Millions, £ in Millions	Jul. 01, 2021 EUR (€)	Jun. 30, 2021 GBP (£)	Jun. 30, 2021 EUR (€)
Disclosure of non-adjusting events after reporting period [line items]
Security deposit to cover legal costs		£ 2.6	€ 3.0
Non Adjusting Event After Reporting Date [Member]
Disclosure of non-adjusting events after reporting period [line items]
Payment of security deposit to cover legal costs	€ 3.0