CERTAIN RELATIONSHIPS AND RELATED PARTY TRANSACTIONS
The following includes a summary of transactions since January 1, 2015 to which we have been a party in which the amount involved exceeded or will exceed $120,000, and in which any of our directors, executive officers or, to our knowledge, beneficial owners of more than 5% of our capital stock or any member of the immediate family of any of the foregoing persons had or will have a direct or indirect material interest, other than equity and other compensation, termination, change in control and other arrangements, which are described under “Executive and Director Compensation.” We also describe below certain other transactions with our directors, executive officers and stockholders.
Formation and Executive Promissory Notes
On October 8, 2013, Jeffrey B. Kindler, our Chief Executive Officer and a member of our board of directors, acquired 320,256 shares of common stock for the purchase price of $1.36 per share. On October 7, 2013, James N. Campbell, M.D., our President and Chief Scientific Officer and one of our directors, acquired 120,000 shares of common stock for the purchase price of $1.36 per share. Mr. Kindler and Dr. Campbell paid for their respective shares of common stock by delivering cash payment to us in an amount equal to the aggregate par value of the shares, and the remainder paid by delivering to us 50% recourse promissory notes, or the Executive Notes, with a principal amount equal to the aggregate purchase price less the aggregate par value of the common stock purchased from us. The Executive Notes accrued interest at a rate of 0.32% per annum and matured on October 8, 2016, and were secured by the respective shares of common stock purchased by Mr. Kindler and Dr. Campbell with the proceeds of the Executive Notes. On April 12, 2018, our board of directors forgave all indebtedness and released all collateral in respect of the Executive Notes.
Preferred Stock Financings and Convertible Notes Financings
2019 Notes. From March 1, 2016 to June 15, 2016, we issued convertible promissory notes in the aggregate principal amount of $30.0 million due 2019, or the 2019 notes. The 2019 notes accrued at an interest rate of 5% per annum. On December 30, 2016, we completed the Series C preferred stock financing described below. At that time, all 2019 notes and the then accrued interest totaling $1,039,835 were converted into 17,244,322 shares of Series C preferred stock. We issued to 2019 note holders and, in compensation for certain services, to Maxim Partners LLC, warrants to purchase an aggregate of 3,068,263 shares of Series C preferred stock. Certain of our officers and/or directors, including Sol J. Barer, Ph.D., James N. Campbell, M.D., Jeffrey B. Kindler and Arnold L. Oronsky, Ph.D., participated in the 2019 notes financing either personally or through affiliated trusts or funds.
Series C Preferred Stock Financing. On December 30, 2016, we issued and sold to investors in a private placement 26,446,984 shares of our Series C preferred stock at a price per share of $1.80, for aggregate consideration of approximately $47.6 million, consisting of $16.6 million in cash proceeds plus the conversion of the 2019 notes in the aggregate amount of approximately $31.0 million. On January 6, 2017, we issued and sold an additional 111,334 shares of our Series C preferred stock for aggregate consideration of approximately $0.2 million. Certain of our officers and/or directors, including Sol J. Barer, Ph.D., James N. Campbell, M.D., Jeffrey B. Kindler and Arnold L. Oronsky, Ph.D., participated in the Series C preferred stock financing either personally or through affiliated trusts or funds.
2018 Notes. From April 28, 2017 to October 10, 2017, we issued convertible promissory notes in the aggregate principal amount of $9.2 million due 2018, or the 2018 notes. The 2018 notes accrued at an interest rate of 10% per annum. On December 18, 2017, we completed the Series D preferred stock financing described below. At that time, all 2018 notes and the then accrued interest totaling $406,306 were converted into 5,328,476 shares of Series D preferred stock. We issued to 2018 note holders warrants to purchase an aggregate of 831,120 shares of Series D preferred stock. In addition, in compensation for certain services, we issued to Brookline Capital Markets a warrant to purchase 18,905 shares of common stock. Certain of our officers and/or directors,
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