Commitments and contingencies Lease commitments In May 2016, the Company entered into a lease amendment (the "2016 Lease") for office and laboratory space occupied under an original lease that commenced in March 2014 and was set to expire in February 2017 (the "2014 Lease"). The 2016 Lease extended the 2014 Lease to February 2020. In June 2015, the Company signed a second operating lease (the "2015 Lease") for office space in the same building as the 2014 Lease. In August 2016, the Company exercised a three -year renewal option extending the 2015 Lease to February 2020. Both the 2015 Lease and the 2016 Lease are classified as operating leases and have remaining lease terms of 11 months at March 31, 2019 . The right of use asset and lease liability were calculated using an estimated incremental borrowing rate of 10% for both the 2015 and 2016 Leases. For both the three months ended March 31, 2019 and March 31, 2018 , rent expense was $0.4 million . In March 2019, the Company entered into an agreement to sublease a portion of the leased space under the 2015 Lease, through the end of the lease term in February 2020. Since the Company retained its obligations under the sublease, it did not adjust the lease liability and instead is accounting for the sublease payments as rental income. Maturities of lease liabilities for both the 2016 Lease and the 2015 Lease are as follows (in thousands): March 31, 2019 2019 $ 1,231 2020 274 Total lease payments 1,505 Less imputed interest (73 ) Total $ 1,432 At March 31, 2019 and December 31, 2018 , the Company has an outstanding letter of credit of $0.3 million with a financial institution related to a security deposit for the 2016 Lease, which is secured by cash on deposit and expires on February 29, 2020. Litigation Beginning on October 31, 2017, three putative class action complaints were filed in the U.S. District Court for the District of Massachusetts (the District of Massachusetts or the Court), naming the Company, Chief Executive Officer William D. Clark, and former Chief Financial Officer Jonathan Poole as defendants. The Court consolidated the three actions into one case, captioned Emerson et al. v. Genocea Biosciences, Inc., et al., Civil Action No. 17-cv-12137-PBS (D. Mass.), and appointed the Genocea Investor Group (a group of five purported shareholders) as lead plaintiff. On March 29, 2018, counsel for the lead plaintiff filed an amended complaint in the District of Massachusetts that alleged violations of the Securities Exchange Act of 1934 and Rule 10b-5 in connection with the Companys disclosures from March 31, 2016 to September 25, 2017 concerning the development of GEN-003. The amended complaint added Seth V. Hetherington, former Chief Medical Officer, to the original named defendants, and sought unspecified damages and costs. On December 6, 2018, the District of Massachusetts granted defendants motion to dismiss the amended complaint for failure to state a claim. On January 7, 2019, the lead plaintiff filed a notice of appeal in the District of Massachusetts regarding the Court order dismissing the amended complaint. The appeal has been docketed in the First Circuit under the caption Yuksel, et al. v. Genocea Biosciences, et al., Civil Action No. 19-1036 (1st Cir.). The Company is unable at this time to determine whether the outcome of the securities action litigation would have a material impact on its results of operations, financial condition or cash flow. Beginning on January 31, 2018, two putative shareholder derivative actions were filed in the U.S. District Court for the District of Delaware, naming certain of the Companys officers and directors (including certain former directors and officers) as defendants, and naming the Company as a nominal defendant. On August 24, 2018, the court consolidated the two actions into one case, captioned In re Genocea Biosciences, Inc. Derivative Litigation, Civil Action No. 18-cv-00186-MN (D. Del.). The operative complaint in the now-consolidated action alleges violations of the Securities Exchange Act of 1934 and Rule 14a-9 in connection with disclosures made in the Companys Schedule 14A Proxy Statement, filed with the SEC on April 21, 2017. The complaint also alleges claims for breach of fiduciary duty, unjust enrichment, and waste of corporate assets. On August 10, 2018, the parties filed a joint stipulation and proposed order agreeing to stay the consolidated action until, inter alia, the entry of an order granting or denying any motion to dismiss the action in the District of Massachusetts, and on August 24, 2018, the court entered the joint stipulation agreeing to stay the consolidated action. In light of the December 6, 2018 order granting defendants motion to dismiss in the District of Massachusetts, the Company and the plaintiffs in the derivative action entered into joint stipulation on February 5, 2019 to stay the derivative action through the duration of the appeal in the securities action. The Company is unable at this time to determine whether the outcome of the derivative litigation would have a material impact on our results of operations, financial condition or cash flows.