In June 2012, the Company entered into a master lease for the Company’s office in Boston, Massachusetts, which was originally set to expire in August 2016, but renewed through August 31, 2021. On April 22, 2021, the Company extended its lease for a portion of office space currently held at the Company's office space in Boston. The renewal of the portion of the Company's office space was originally set to expire on August 31, 2021, but has now been extended through August 31, 2026. As of December 31, 2021, and December 31, 2020, a total security deposit of $0.1 million is included in deposits on the Company’s balance sheet. In December 2021, the Company made the decision to move its operations away from its former corporate office in Boston. As described in Note 3, Summary of Significant Accounting Policies, the Company's change in the intended use of the Boston office represented an indicator of impairment. We determined the aggregate carrying value of the asset group (approximately $1.4 million) was in excess of the aggregate estimated fair value and recorded an impairment charge of $0.6 million to the right-of-use asset and approximately $0.1 million to associated property and equipment. The fair value was determined based on the amount and timing of estimated net future cash flows, discounted at a risk-adjusted rate of 10%. The Boston office has been fully vacated as of December 31, 2021.

On January 30, 2018, the Company entered into a lease agreement for office space in Houston, Texas at MD Anderson. Under the terms of the Houston lease agreement, the Company leased approximately 210 square feet and was required to make rental payments at an average monthly rate of approximately $1,000. This lease was terminated effective March 31, 2020.

On March 12, 2019, the Company entered into a lease agreement for office and lab space in Houston, Texas at MD Anderson through April 2021. Under the terms of the lease agreement, the Company leases approximately 1,038 square feet and was required to make rental payments at an average monthly rate of approximately $2,000 through April 2021. On October 15, 2019, the Company entered into a lease agreement for additional office and laboratory space in Houston through February 2027. Under the terms of the lease, the Company leases from MD Anderson, approximately 8,443 square feet and is initially required to make rental payments of approximately $17,000 per month through February 2027, subject to an annual base rent increase of approximately 3.0% throughout the term. Effective April 7, 2020, the Company leased an additional 5,594 square feet from MD Anderson. The Company is initially required to make rental payments of approximately $12,000 per month through February 2027, subject to an annual base rent increase of approximately 3.0% throughout the term.

On December 15, 2020, we entered into a second agreement with MD Anderson to lease additional space on MD Anderson’s campus (the “2020 Lease”). As of December 31, 2021, the Company has approximately 32,148 square feet under lease from MD Anderson. The Company is initially required to make rental payments of approximately $37,000 per month through April 2028, subject to an annual base rent increase of approximately 3.0% throughout the term beginning in April 2023. The 2020 Lease may be extended for one additional five-year term at our election.

The components of lease expense were as follows:


	Year Ended December 31,
($ in thousands)	2021			2020
Operating lease cost	$	1,394		$	1,054
Total lease cost	$	1,394		$	1,054
Weighted-average remaining lease term (years)		5.58			6.19
Weighted-average discount rate		8.00	%		8.00	%

Cash paid for amounts included in the measurement of the lease liabilities were $1.3 million for the year-ended December 31, 2021. The Company recognized new operating lease assets obtained in exchange for operating lease liabilities of $1.4 million for the year-ended December 31, 2021.

As of December 31, 2021, the maturities of the Company’s operating lease liabilities were as follows (in thousands):


Maturity of Lease Liabilities	Operating Leases
2022		1,102
2023		1,132
2024		1,166
2025		1,201
2026		1,121
Thereafter		752
Total lease payments		6,474
Less: imputed interest		(1,227	)
Present value of lease payments	$	5,247