JRP Group's overall total new business sales grew by 13% on a pro forma basis to £436m in the three months to the end of March.
The group said this was driven by a large increase in defined benefit de-risking volumes, partly offset by more normal levels of mortgage advances.
Sales were up 92% compared to the statutory Q116 level, which excluded Partnership.
DB sales were 191% higher (pro forma) at £125m.
The group said DB de-risking growth prospects remained very positive.
It said guaranteed income for life sales were up 7% (pro forma) to £174m, helped by a stabilising market and demographic growth.
Care sales were £17m due to increased pricing selectivity, offsetting the increase in GIfL.
Lifetime mortgage advances fell by 29% (pro forma) against a tough comparator.
Group chief executive Rodney Cook said: "While maintaining our strong focus on margins and profit growth, I am delighted that we have also been able to grow sales in the first quarter of 2017.
"Our core GIfL and DB products both grew well, confirming the momentum of these segments.
"The DB market offers sustained growth, and our pipeline in the below £250m segment remains very encouraging.
"Our profit focus should deliver IFRS new business margins in excess of the mid 6% range and we remain on track to deliver a sustainable mid-teen IRR3 on shareholder capital deployed in new business by year-end 2018.
"This will be helped by the progress being made with the £45m merger cost saving programme.
"Along with a number of other firms, we have been granted Prudential Regulation Authority (PRA) approval to publish a single group Solvency and Financial Condition Report on 30 June.
"In common with most UK life companies, our capital position benefits from a significant transitional, in line with the PRA's stance that recognises transitionals as long term capital.
"The directors remain comfortable that the Group's capital position is appropriate to deliver the growth and returns that we are targeting.
"Overall we have enjoyed a solid start to the year and we remain on track to meet our expectations."